Android Studio: Start another activity

Respond to the Send button

file app > java > com.example.myfirstapp > MainActivity, add the following sendMessage() method stub:

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    /** Called when the user taps the Send button */
    public void sendMessage(View view) {
        // Do something in response to button
    }
}

Klik View > Alt+Enter > Import class

file app > res > layout > activity_main.xml

• klik button > Attribute > onClick property > sendMessage [MainActivity]

Build an intent

Tambahkan di MainActivity

public class MainActivity extends AppCompatActivity {
    public static final String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    /** Called when the user taps the Send button */
    public void sendMessage(View view) {
        Intent intent = new Intent(this, DisplayMessageActivity.class);
        EditText editText = (EditText) findViewById(R.id.editTextTextPersonName);
        String message = editText.getText().toString();
        intent.putExtra(EXTRA_MESSAGE, message);
        startActivity(intent);
    }
}

Tambahkan

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

Create the second activity

Lakukan:

• Project window > app (Right Click) > New > Activity > Empty Activity.
• Configure Activity window

 ActivityName   DisplayMessageActivity
 Finish

Add a text view

• app > res > layout > activity_display_message.xml.
• Enable Autoconnection to Parent
• Palette panel > Text, TextView (di drag ke layout)
• Jika di perlukan tambahkan constraint
• set textSize

Display the message

In DisplayMessageActivity

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_display_message);
    
    // Get the Intent that started this activity and extract the string
    Intent intent = getIntent();
    String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE); 

    // Capture the layout's TextView and set the string as its text
    TextView textView = findViewById(R.id.textView);
    textView.setText(message);
}

tambahkan

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

Add upward navigation

Menambahkan Up button, file app > manifests > AndroidManifest.xml,

<activity android:name=".DisplayMessageActivity"
          android:parentActivityName=".MainActivity">
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value=".MainActivity" />
</activity>

Referensi

• https://developer.android.com/training/basics/firstapp/starting-activity