Using SubActivities in Android

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Sometimes you need to run some Activity, do some operation there and return some value to parent Activity. For this situation Android has possibility to run Activity for result.

I am going to show how to use it.

There are 3 things which you should do:

1) you need to run your subactivity via this method

startActivityForResult(Intent i, int requestCode);

2) in parent activity you should override method

onActivityResult(int requestCode, int resultCode, Intent data)

3) in subactivity you need to put result and finish this activity

setResult(int resultCode, Intent data);

finish();

As you see it is simple.

Now I am going to show whole example:

First off all need to create Parent (Main) activity:

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

/**
 * Parent activty
 *
 * @author FaYnaSoft Labs
 */
public class Main extends Activity {
	protected static final int SUB_ACTIVITY_REQUEST_CODE = 100;

	TextView tv;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		tv = (TextView) findViewById(R.id.textId);
		tv.setText("TextView element");
		Button b = (Button) findViewById(R.id.btnId);
		b.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				Intent i = new Intent(Main.this,
						SubActivity.class);
				startActivityForResult(i, SUB_ACTIVITY_REQUEST_CODE);
			}
		});
	}

	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		super.onActivityResult(requestCode, resultCode, data);
		if(requestCode == SUB_ACTIVITY_REQUEST_CODE){
				Bundle b = data.getExtras();
				tv.setText(b.getString("TEXT"));
        }
	}
}

As you see here we start activity for result and we override onActivityResult method.
Also simple main layout:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

 android:orientation="vertical" android:layout_width="fill_parent"

 android:layout_height="fill_parent">

 <TextView android:id="@+id/textId" android:layout_width="wrap_content"

 android:layout_height="wrap_content" />

 <Button android:id="@+id/btnId" android:layout_width="wrap_content"

 android:layout_height="wrap_content" android:text="Click" />

</LinearLayout>

Now we need sub activity:

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class SubActivity extends Activity {
	public final static int SUCCESS_RETURN_CODE = 1;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.subactivity);
		final EditText editView = (EditText) findViewById(R.id.editId);
		editView.setText("SubActivity");
		Button button = (Button) findViewById(R.id.btnId);
		button.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				Intent intent = new Intent();
				Bundle b = new Bundle();
				b.putString("TEXT", editView.getText().toString());
				intent.putExtras(b);
				setResult(SUCCESS_RETURN_CODE, intent);
				finish();
			}
		});
	}
}

Here we put result for main activity.
Also layout for subactivity

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<EditText android:id="@+id/editId" android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<Button android:id="@+id/btnId" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="Click" />
</LinearLayout>

As you see it is very easy to get data from sub activity.

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