android-java-two-activity

👉 Step 1:

Create a new app with empty activity.

👉 Step 2:

Creating a new empty activity, name is: activity_second

👉 Step 3:

Add some values into re/values/strings.xml:

<string name="tv_activity1_text">This is the 1st Activity</string>
<string name="tv_activity2_text">This is the 2nd Activity</string>
<string name="btn_activity1_text">Open the 2nd activity</string>
<string name="btn_activity2_text">Go back to the 1st Activity</string>
<string name="toast_activity1_text">Button is pressed on activity 1</string>
<string name="toast_activity2_text">Button is pressed on activity 2</string>

👉 Step 4:

Add a Button and modify the TextView in activity_main.xml

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/tv_activity1_text"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button_activity2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/btn_activity1_text"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView"
        tools:text="@string/btn_activity1_text" />

👉 Step 5:

Modify activity_second.xml layout:

 <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/tv_activity2_text"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button_activity2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/btn_activity2_text"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView"
        tools:text="@string/btn_activity2_text" />

👉 Step 6:

Update the java code of MainActivity.java file, add uiChanger() method. Use the following imports:

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

You will see, when the activity is destroyed.

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

    private void uiChanger(){
        Button button = findViewById(R.id.button_activity2);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(MainActivity.this, R.string.toast_activity1_text, Toast.LENGTH_LONG).show();
                Intent intent = new Intent();
                intent.setClass(MainActivity.this, activity_second.class);
                startActivity(intent);
            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("TwoActivityApp", "1st activity onDestroy...");
    }

👉 Step 7:

Update the activity_second.java file. First you can use intent, but you will see the previous activity was in stack, so we are using the finish() method.

Use the following imports:

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        uiChanger();
    }
    private void uiChanger(){
        Button button = findViewById(R.id.button_activity2);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Toast.makeText(activity_second.this, R.string.toast_activity2_text, Toast.LENGTH_LONG).show();
                //Intent intent = new Intent();
                //intent.setClass(activity_second.this, MainActivity.class);
                //startActivity(intent);
                finish();
            }
        });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("TwoActivityApp", "2nd activity onDestroy...");
    }

👍 Finally you can check the app, the logs will be visible in LogCat. Use the tag TwoActivityApp to filter the logcat.