Android message notification dialog on top of other activities

问题

How do I get an Android message notification dialog on top of other activities?

I am searching for a solution to this problem and still not yet got the solution. Right now, I am developing a social networking app in which I need to show a notification message dialog whenever the user gets some message from another and to achieve that I have used the broadcast receiver and it is working fine.

The problem is how to show the notification dialog on top of another application.

回答1:

Yes, it is possible. The Main.xml layout has one edit text and button. The Messagebox layout has one button. Here you can change message layout to whatever you want.

File MyScheduledReceiver.java:

public class MyScheduledReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub

        Intent scheduledIntent = new Intent(context, MessageBox.class);
        scheduledIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(scheduledIntent);
    }
}

Main Activity:

public class AndroidMessageBoxActivity extends Activity implements OnClickListener
{
    private EditText time;
    private Button btn;
    private AlarmManager alarm;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        time = (EditText) findViewById(R.id.editText1);
        btn = (Button) findViewById(R.id.button1);
        alarm = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

        btn.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        int x = Integer.parseInt(time.getText().toString());

        Intent intent = new Intent(this, MyScheduledReceiver.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(
                this.getApplicationContext(), 234324243, intent, 0);

        alarm.set(AlarmManager.RTC_WAKEUP,
                  System.currentTimeMillis() + (x * 1000),
                  pendingIntent);
        Toast.makeText(this,
                       "Alarm set in " + x + " seconds",
                       Toast.LENGTH_LONG).show();
    }
}

MessageBox:

public class MessageBox extends Activity
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.messagebox);

        Button btn = (Button) findViewById(R.id.Ok);
        btn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                finish();
            }
        });
    }
}

And add these two lines in the Android manifest XML file:

<receiver android:name="MyScheduledReceiver"></receiver>

<activity android:name="MessageBox" android:theme="@style/Theme.Transparent"></activity>

Filestyle.xml:

<resources>
    <style name="Theme.Transparent" parent="android:Theme">
        <item name="android:windowIsTranslucent">true</item>
        <item name="android:windowContentOverlay">@null</item>
        <item name="android:windowBackground">@android:color/transparent</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:backgroundDimEnabled">false</item>
    </style>
</resources>

回答2:

As others have said in their responses, launching an Activity from the background in order to get the user's attention is discouraged. However, some situations call for this; examples in Android itself include clock alarms, incoming calls, and low battery alerts.

In Gingerbread the fullScreenIntent field was added to Notification objects; this is a standard and convenient way to post a Notification that also launches an Activity to really get the user's attention. As of Gingerbread, the platform components I listed above (alarms, etc.) all use this technique to show their alerts. This is the recommended way to do what you're asking.