Intent and putExtra

Switching between activities in Android and sending data.

Sample pictures

Java code

package com.example.IntentPutextra;
 
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
 
public class MainActivity extends AppCompatActivity {
 
    private static final String TAG = "MainActivity";
    Button button;
    EditText editText;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        Log.i(TAG, "m1_onCreate: ");
 
        button = findViewById(R.id.button);
        editText = findViewById(R.id.editText);
 
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
 
                String str = editText.getText().toString();
 
                Intent intent = new Intent(MainActivity.this,Main2Activity.class);
 
                intent.putExtra("ET",str);
 
                startActivity(intent);
            }
        });
 
    }
 
    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "m1_onResume: ");
    }
 
    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "m1_onStop: ");
    }
 
    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "m1_onPause: ");
    }
}

package com.example.IntentPutextra;

import android.content.Intent;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

private static final String TAG = "MainActivity";

Button button;

EditText editText;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

Log.i(TAG, "m1_onCreate: ");

button = findViewById(R.id.button);

editText = findViewById(R.id.editText);

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

String str = editText.getText().toString();

Intent intent = new Intent(MainActivity.this,Main2Activity.class);

intent.putExtra("ET",str);

startActivity(intent);

}

});

}

@Override

protected void onResume() {

super.onResume();

Log.i(TAG, "m1_onResume: ");

}

@Override

protected void onStop() {

super.onStop();

Log.i(TAG, "m1_onStop: ");

}

@Override

protected void onPause() {

super.onPause();

Log.i(TAG, "m1_onPause: ");

}

package com.example.IntentPutextra;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class Main2Activity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    TextView textView;
    MainActivity mm = new MainActivity();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Log.i(TAG, "m2_onCreate: ");

        textView = findViewById(R.id.textView);
        Bundle bundle = getIntent().getExtras();

        if (bundle != null) {
            String s = bundle.getString("ET");
            textView.setText(s);
        }

    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "m2_onResume: ");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "m2_onStop: ");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "m2_onPause: ");
    }
}