How to make Activity running on the home screen?

Question

I'm creating application to show dialog activity each specific time (specified by the user). I used Timer to do this and everything is fine. However when I go back to home screen the dialog activity is not appearing there only keep showing on the main activity because once I open the application again I found number of dialog activities already opened by the timer. So how I can make that dialog activity keep showing any where in the device?

The Code:

                tt = new TimerTask() 
                {
                    @Override
                    public void run() {
                        runOnUiThread(new Runnable() {

                            @Override
                            public void run() {
                                Intent openD = new Intent(MainActivity.this,Dialog.class);
                                openD.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                startActivity(openD);

                            }
                        });
                    }      
                };
                t = new Timer();
            t.schedule(tt,0,5000);

Answer 1

尝试查看后台服务 。

Answer 2

Because, when you go to home button your Activity goes into pause state and then destroys hence it doesn't, put your timer logic in a Service and call you activity from there, in this way when you go back to home screen you logic still remain in running state.

Do read lifecycle of Activity & Service in Android

http://developer.android.com/guide/components/services.html

Also as a note, if you want your activity to pop up all the time on certain events, make sure you make your Service persistable.