//FOR OPTION MENU
//activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"/>
    
//mainactivity.java
package com.example.menu;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        switch(item.getItemId()) {
            case R.id.mail:
                getWindow().getDecorView().setBackgroundColor(Color.RED);
                return true;

            case R.id.upload:
                getWindow().getDecorView().setBackgroundColor(Color.GREEN);
                return true;

            case R.id.share:
                getWindow().getDecorView().setBackgroundColor(Color.BLUE);
                return true;
            default: return super.onOptionsItemSelected(item);
        }
    }
    public void display(String x)
    {
        Toast.makeText(this,x, Toast.LENGTH_SHORT).show();
    }

}

//for menu.xml of value menu

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/mail"
        android:title="red"
        android:icon="@drawable/ic_round_outlet_24"
        app:showAsAction="always"
        />

    <item
        android:id="@+id/upload"
        android:icon="@android:color/holo_green_dark"
        android:title="green" />
    <item
        android:id="@+id/share"

        android:title="blue"
        android:icon="@drawable/ic_round_outlet_24"
        app:showAsAction="always" />

</menu>


//FOR CONTEXT MENU

//activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

//mainactivity.java
package com.example.contextmenu;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TextView t=findViewById(R.id.textview);
        registerForContextMenu(t);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        menu.setHeaderTitle("choose your option");
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu,menu);
    }

    @Override
    public boolean onContextItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId()) {
            case R.id.op1:
                Toast.makeText(this, "option1 selected", Toast.LENGTH_SHORT).show();
                return true;
            case R.id.op2:
                Toast.makeText(this, "option2 selected", Toast.LENGTH_SHORT).show();
                return true;

            default:
                return super.onContextItemSelected(item);

        }
    }}
    
//menu.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:id="@+id/op1"
        android:title="option1"/>
    <item
        android:id="@+id/op2"
        android:title="option2"/>
</menu>


//FOR POPUPMENU
//activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="show popup"
        android:onClick="showpopup"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />


</androidx.constraintlayout.widget.ConstraintLayout>


//for mainactivity.java
package com.example.popmenu;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.PopupMenu;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements PopupMenu.OnMenuItemClickListener{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void showpopup(View v)   //on click ha
    {
        PopupMenu popup = new PopupMenu(this, v);
        popup.inflate(R.menu.popmenu);
        popup.show();
        popup.setOnMenuItemClickListener(this);
    }

    @Override
    public boolean onMenuItemClick(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.item1:
                Toast.makeText(getApplicationContext(), "option1 selected", Toast.LENGTH_SHORT).show();
                return true;
            case R.id.item2:
                Toast.makeText(getApplicationContext(), "option2 selected", Toast.LENGTH_SHORT).show();
                return true;
            default:
                return super.onContextItemSelected(item);
        }
    }

}

//popmenu.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">


    <item
        android:id="@+id/item1"
        android:title="Item1"/>

    <item
        android:id="@+id/item2"
        android:title="Item2"/>

</menu>


//FOR SHARED PREFERENCES
//activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.023"
        tools:layout_editor_absoluteX="0dp"
        tools:text="Here will be our text" />

    <EditText
        android:id="@+id/edittext"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.154"
        tools:layout_editor_absoluteX="0dp" />

    <Button
        android:id="@+id/apply_text_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="apply text"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.08"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.273" />

    <Switch
        android:id="@+id/swi"
        android:layout_width="91dp"
        android:layout_height="62dp"
        android:layout_gravity="center_horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.351" />

    <Button
        android:id="@+id/save_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="save data"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.945"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.273" />


</androidx.constraintlayout.widget.ConstraintLayout>



//for mainactivity.java
package com.example.fragments;  //naam fragment galti se ha

import androidx.appcompat.app.AppCompatActivity;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private TextView textView;
    private EditText editText1;
    private Button applyTextButton;
    private Button saveButton;
    private Switch swi;

    public static final String SHARED_PREFS = "sharedPrefs";
    public static final String TEXT = "text";
    public static final String SWITCH = "switch";

    private String text;
    private boolean switchOnOff;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = (TextView) findViewById(R.id.textview);
        editText1 = (EditText) findViewById(R.id.edittext);
        applyTextButton = (Button) findViewById(R.id.apply_text_button);
        saveButton = (Button) findViewById(R.id.save_button);
        swi = (Switch) findViewById(R.id.swi);

        applyTextButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                textView.setText(editText1.getText().toString());
            }
        });
        saveButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                saveData();
            }
        });
        loadData();
        updateData();

    }
    public void saveData()
    {
        SharedPreferences sp=getSharedPreferences(SHARED_PREFS,MODE_PRIVATE);
        SharedPreferences.Editor ed=sp.edit();
        ed.putString(TEXT,textView.getText().toString());
        ed.putBoolean(SWITCH,swi.isChecked());
        ed.apply();
        Toast.makeText(this, "DATA SAVED", Toast.LENGTH_SHORT).show();
    }
    public void loadData()
    {
        SharedPreferences sp=getSharedPreferences(SHARED_PREFS,MODE_PRIVATE);
        text=sp.getString(TEXT," ");
        switchOnOff=sp.getBoolean(SWITCH,false);
    }
    public void updateData()
    {
       textView.setText(text);
       swi.setChecked(switchOnOff);
    }
}

//FOR SEEKBAR
//for activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/message_id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="IDLI"
        android:textSize="20sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.452"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.174" />

    <SeekBar
        android:id="@+id/seekbar"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:max="150"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:layout_editor_absoluteX="28dp" />

</androidx.constraintlayout.widget.ConstraintLayout>

//for activitymain.java
package com.example.seekbar;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    TextView t;
    SeekBar s;
    int textsize=20;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        t=findViewById(R.id.message_id);
        s=findViewById(R.id.seekbar);

        t.setTextSize(textsize);


        s.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            int p=0;
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                      textsize=textsize+(progress-p);
                      p=progress;
                      t.setTextSize(textsize);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
    }
}


//AUTOCOMPLETE TEXTVIEW

public class MainActivity extends AppCompatActivity {  
    String[] language ={"C","C++","Java",".NET","iPhone","Android","ASP.NET","PHP"};  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
      
        ArrayAdapter<String> adapter = new ArrayAdapter<String>  
                (this,android.R.layout.select_dialog_item,language);  
        
        AutoCompleteTextView actv =  (AutoCompleteTextView)findViewById(R.id.autoCompleteTextView);  
        actv.setThreshold(1);
        actv.setAdapter(adapter);
        actv.setTextColor(Color.RED);  
    }  
}  


//DATE PICKER
public class MainActivity extends AppCompatActivity {
    DatePicker picker;
    Button btnGet;
    TextView tvw;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tvw=(TextView)findViewById(R.id.textView1);
        picker=(DatePicker)findViewById(R.id.datePicker1);
        btnGet=(Button)findViewById(R.id.button1);
        btnGet.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                tvw.setText("Selected Date: "+ picker.getDayOfMonth()+"/"+ (picker.getMonth() + 1)+"/"+picker.getYear());
            }
        });
    }
}

//CUSTOM TOGGLE
MainActivity.java
public class MainActivity extends AppCompatActivity {
Button b1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       b1= findViewById(R.id.button);
        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showToast();
            }
        });
    }
 public void showToast()
    {
      LayoutInflater inflater = getLayoutInflater();
      View layout = inflater.inflate(R.layout.custom, (ViewGroup) findViewById(R.id.toast_root));
      Toast toast = new Toast(getApplicationContext());
      toast.setGravity(Gravity.CENTER,0,0);
      toast.setDuration(Toast.LENGTH_LONG);
      toast.setView(layout);
      toast.show();
    }
}  

//ALERT DIALOG

import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void exit(View view){
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
        alertDialogBuilder.setTitle("Confirm Exit..!!!");
        alertDialogBuilder.setIcon(R.drawable.question);
        alertDialogBuilder.setMessage("Are you sure,You want to exit");
        alertDialogBuilder.setCancelable(false);
   }
   
   alertDialogBuilder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {

                            @Override
                            public void onClick(DialogInterface arg0, int arg1) {
                                finish();
                            }
                        });

                alertDialogBuilder.setNegativeButton("No", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Toast.makeText(MainActivity.this,"You clicked over No",Toast.LENGTH_SHORT).show();
                            }
                        });
                alertDialogBuilder.setNeutralButton("Cancel", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                Toast.makeText(getApplicationContext(),"You clicked on Cancel",Toast.LENGTH_SHORT).show();
                            }
                         });

        AlertDialog alertDialog = alertDialogBuilder.create();
        alertDialog.show();
    }
}

//SPINNER

package com.example.spinner;

import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity{

    String[] country={"INDIA","CHINA","CANADA"};
    Spinner spin;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        spin=findViewById(R.id.spinner);

        ArrayAdapter<String> ada= new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_spinner_dropdown_item,country);
        ada.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        spin.setAdapter(ada);
        
        spin.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                switch (position){
                    case 0:getWindow().getDecorView().setBackgroundColor(Color.RED);
                    break;
                    case 1:getWindow().getDecorView().setBackgroundColor(Color.BLUE);
                    break;
                    case 2:getWindow().getDecorView().setBackgroundColor(Color.GREEN);
                    break;
                }
                Toast.makeText(MainActivity.this, "counttry is "+country[position], Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });
    }
}


//LISTVIEW

package com.example.listview;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    ListView l;
    String country[] = {"India", "China", "australia", "Portugle", "America", "NewZealand"};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        l=findViewById(R.id.lextview);

        ArrayAdapter ada=new ArrayAdapter(getApplicationContext(),R.layout.activity_listview,R.id.textView,country);
        l.setAdapter(ada);

        l.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this, "country is "+country[position], Toast.LENGTH_SHORT).show();
            }
        });

    }
}


//CUSTOM LISTVIEW

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/simpleView"
        android:divider="@color/colorPrimary"
        android:dividerHeight="1dp"/>

</LinearLayout>

activity_listview.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/icon"
        android:layout_width="50dp"
        android:layout_height="50dp"
        />

    <TextView
     android:id="@+id/textView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:padding="15dp"
    android:textColor="#FF9800" />
</LinearLayout>

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ListView;

public class MainActivity extends AppCompatActivity {

    ListView simpleList;
    String countryList[] = {"India", "Australia", "America"};
    int flags[] = {R.drawable.india, R.drawable.australia, R.drawable.america};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        simpleList = findViewById(R.id.simpleView);
        CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), countryList, flags);
        simpleList.setAdapter(customAdapter);
    }
}

CustomAdapter.java

package com.sindhu.customlist;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class CustomAdapter extends BaseAdapter {
    Context context;
    String CountryList[];
    int flags[];
    LayoutInflater inflter;

public CustomAdapter(Context context, String[] countryList, int[] flags) {
        this.context = context;
        CountryList = countryList;
        this.flags = flags;
        this.inflter = (LayoutInflater.from(context)); // Create a new LayoutInflater instance associated with a particular Context
    }
@Override
    public int getCount() {
        return CountryList.length;
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }
    
 @Override
    public View getView(int position, View view, ViewGroup parent) {
        view = inflter.inflate(R.layout.activity_listview,null);
        TextView country = view.findViewById(R.id.textView);
        ImageView icon = view.findViewById(R.id.icon);
        country.setText(CountryList[position]);
        icon.setImageResource(flags[position]);
        return view;
    }
}

// FRAGMENT LIFECYCLE
// activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <fragment
        android:id="@+id/test_fragment"
        class="com.example.fragment.TestFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:layout="@layout/fragment_test"/>

</RelativeLayout>


// fragment_test.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="Please Check Logcat.!!!"
        android:textColor="#000"
        android:textSize="25sp" />


</LinearLayout>

//TestFragment.java

package com.example.fragment;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;

public class TestFragment extends Fragment {

    private void printLog(String s) {

        Log.d("LifeCycle:", s);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        printLog("onActivityCreated Called");
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.fragment_test, container, false);
        printLog("onCreateView Called");

        return v;
    }
    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        printLog("onViewCreated Called");

    }

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        printLog("onAttach Called");
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        printLog("onCreate Called");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        printLog("onDestroy Called");
    }
    @Override
    public void onDestroyView() {
        super.onDestroyView();
        printLog("onDestroyView Called");
    }

    @Override
    public void onDetach() {
        super.onDetach();
        printLog("onDetach Called");
    }

    @Override
    public void onPause() {
        super.onPause();
        printLog("onPause Called");
    }
    @Override
    public void onResume() {
        super.onResume();
        printLog("onResume Called");
    }

    @Override
    public void onStart() {
        super.onStart();
        printLog("onStart Called");
    }

    @Override
    public void onStop() {
        super.onStop();
        printLog("onStop Called");
    }

}


///SIMPLE FRAGMENT BUTTON
// SimpleFragment.java
package com.example.fragquestion;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import androidx.fragment.app.Fragment;

public class SimpleFragment extends Fragment {

    View view;
    Button firstButton;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        view = inflater.inflate(R.layout.fragmentsimple, container, false);
        firstButton = (Button) view.findViewById(R.id.firstButton);

        firstButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getActivity(), "Fragment's Button", Toast.LENGTH_LONG).show();
            }
        });
        return view;
    }
    }


// FRAGMENT SPLIT
// ACTIVITY_MAIN.XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <fragment
        android:id="@+id/fragment1"
        android:layout_width="0px"
        class="com.example.splitfrag.Fragment1"
        android:layout_height="match_parent"
        android:layout_weight="1"
       tools:layout="@layout/fragment1"
        />

    <fragment
        android:id="@+id/fragment2"
        android:layout_width="0px"
        class="com.example.splitfrag.Fragment2"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:layout="@layout/fragment2"
        />


</LinearLayout>

// FRAGMENT1.JAVA
package com.example.splitfrag;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

public class Fragment1 extends Fragment{


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        return inflater.inflate(R.layout.fragment1,container,false);
    }

}

// FRAGMENT2.JAVA

package com.example.splitfrag;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.fragment.app.Fragment;

public class Fragment2 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        return inflater.inflate(R.layout. fragment2, container, false);
    }


}

//FRAGMENT1.XML

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#3F51B5"
    tools:context=".Fragment1">


    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="DIDI" />

</FrameLayout>

//FRAGMENT2.XML

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FF5722"
    tools:context=".Fragment2">


    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="MUMMA" />

</FrameLayout>


//SQLITE

// activityMain.java

package com.example.database;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
EditText name,contact,dob;
Button insert,update,delete,view;
DbHelper db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
name = findViewById(R.id.name);
contact = findViewById(R.id.contact);
dob = findViewById(R.id.dob);
insert = findViewById(R.id.insert);
update = findViewById(R.id.update);
delete = findViewById(R.id.delete);
view = findViewById(R.id.view);
db = new DbHelper(this);
insert.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String nameTxt = name.getText().toString();
String contactTxt = contact.getText().toString();
String dobTxt = dob.getText().toString();
Boolean insertData = db.insertUserData(nameTxt,contactTxt,dobTxt);
if(insertData){
Toast.makeText(MainActivity.this, "New Data Inserted", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(MainActivity.this, "Insertion Failed", Toast.LENGTH_SHORT).show();
}
}

});
insert.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String nameTxt = name.getText().toString();
String contactTxt = contact.getText().toString();
String dobTxt = dob.getText().toString();
Boolean insertData = db.insertUserData(nameTxt,contactTxt,dobTxt);
if(insertData){
Toast.makeText(MainActivity.this, "New Data Inserted", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(MainActivity.this, "Insertion Failed", Toast.LENGTH_SHORT).show();
}
}
});
update.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String nameTxt = name.getText().toString();
String contactTxt = contact.getText().toString();
String dobTxt = dob.getText().toString();
Boolean updateData = db.updateUserData(nameTxt,contactTxt,dobTxt);
if(updateData){
Toast.makeText(MainActivity.this, "Data Updated", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(MainActivity.this, "Updation Failed", Toast.LENGTH_SHORT).show();
}
}
});
delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String nameTxt = name.getText().toString();
Boolean deleteData = db.deleteUserData(nameTxt);
if(deleteData){
Toast.makeText(MainActivity.this, "Data Deleted", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(MainActivity.this, "Deletion Failed", Toast.LENGTH_SHORT).show();
}
}
});
view.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
Cursor res = db.getUserData();
if(res.getCount()==0){
Toast.makeText(MainActivity.this, "No Data Exists", Toast.LENGTH_SHORT).show();
return;
}
StringBuffer buffer = new StringBuffer();
while(res.moveToNext()){
buffer.append("Name: "+res.getString(0)+"\n");
buffer.append("Contact: "+res.getString(1)+"\n");
buffer.append("Date of Birth: "+res.getString(2)+"\n\n");
}
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setCancelable(true);
builder.setTitle("User Data");
builder.setMessage(buffer.toString());
builder.show();
}
});
}
}
    
//DbHelper.java

package com.example.database;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DbHelper extends SQLiteOpenHelper {
public DbHelper(Context context){
super(context,"Userdata.db",null,1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE Userdetails(name TEXT PRIMARY KEY,contact TEXT,dob TEXT)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE if exists Userdetails");
}

public Boolean insertUserData(String name, String contact, String dob){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("name",name);
contentValues.put("contact",contact);
contentValues.put("dob",dob);
long res = db.insert("Userdetails",null,contentValues);
if(res == -1){
return false;
}else
return true;
}
public Boolean updateUserData(String name, String contact, String dob){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("contact",contact);
contentValues.put("dob",dob);
Cursor cursor = db.rawQuery("SELECT * FROM Userdetails WHERE name=?",new String[]{name});
if(cursor.getCount()>0){
long res = db.update("Userdetails",contentValues,"name=?",new String[]{name});
if(res == -1){
return false;
}else
return true;
}else
return false;
}
public Boolean deleteUserData(String name){
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM Userdetails WHERE name=?",new String[]{name});
if(cursor.getCount()>0){
long res = db.delete("Userdetails","name=?",new String[]{name});
if(res == -1){
return false;
}else
return true;
}else
return false;
}
public Cursor getUserData(){
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM Userdetails",null);
return cursor;
}
}



//FOR INTENT
//main.java 2 buttons are there and main2 and activity2 bhi bananai ha

package com.example.newintent;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button explicit_btn = findViewById(R.id.explicit);
        Button implicit_btn =  findViewById(R.id.implicit);


        implicit_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i =new Intent(Intent.ACTION_VIEW);
                i.setData(Uri.parse("http://www.google.com"));
                startActivity(i);
            }
        });
        explicit_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent i=new Intent(getBaseContext(),MainActivity2.class);
                 i.putExtra("key1", "I am value1");
                 i.putExtra("key2", "I am value2");
                startActivity(i);
            }
        });


    }
}

//main2.java
 String a = getIntent().getStringExtra("key1");
        Toast.makeText(this, "a is"+a, Toast.LENGTH_SHORT).show();