Develop Reference

What permission is SHOW_ON_LOCK_SCREEN in MIUI? And how to programatically enable it?

I simply want to show an Activity in Lock Screen but because of this unknown or special permission called SHOW_ON_LOCK_SCREEN in MIUI, I can't make it work.
I've tried the following code but no luck.
<uses-permission android:name="android.permission.WAKE_LOCK" />
public class FloatingWindow extends AppCompatActivity {
PowerManager powerManager;
PowerManager.WakeLock wakeLock;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
//First Attempt
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON|
WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD|
WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED|
WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
setContentView(R.layout.floating_window);
//Second Attempt
powerManager = (PowerManager) getSystemService(POWER_SERVICE);
wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, String.valueOf(getApplicationContext()));
wakeLock.acquire();
}
#Override
public void onDestroy(){
super.onDestroy();
wakeLock.release();
}
}
Here's a thing, It works on other android phone except MIUI. I've tried manually enabling SHOW_ON_LOCK_SCREEN and works.
What exactly is SHOW_ON_LOCK_SCREEN? I can't find it in Android documentation, How are we supposed to programatically enable it?
I noticed that some of my app successfully enable it without me having manually enable it.

how to keep app running when screen off or open another app?

How to keep app running when screen off or open another app,just like some running track app . when user running they can also track user's pace.
I don't know how to start with.

You can use android.permission.WAKE_LOCK permission.
First add this permission in manifest.
<uses-permission android:name="android.permission.WAKE_LOCK" />
In your activity :
import android.os.PowerManager;
public class MyActivity extends Activity {
protected PowerManager.WakeLock mWakeLock;
#Override
public void onCreate(final Bundle icicle) {
setContentView(R.layout.main);
/* This code together with the one in onDestroy()
* will make the screen be always on until this Activity gets destroyed. */
final PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
this.mWakeLock = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "My Tag");
this.mWakeLock.acquire();
}
#Override
public void onDestroy() {
this.mWakeLock.release();
super.onDestroy();
}
}
Or you can add this code before setContentView activity. like this:
#Override
public void onCreate(final Bundle icicle) {
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
setContentView(R.layout.main);
}

android: which wake_lock should we be using

The android documentation says that I should be using
WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
instead of
PowerManager.SCREEN_DIM_WAKE_LOCK. The link is here
But when I try to use it I get an exception saying it is an invalid lock level. I'm using API level 18, here is the code that fails.
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON, "My Tag");
Has anybody tried this? Does it work?

As per the API documentation one should be using the Window.addFlags() for keeping the screen on.
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

The code below is working fine, check this
import android.os.PowerManager;
public class MyActivity extends Activity {
protected PowerManager.WakeLock mWakeLock;
#Override
public void onCreate(final Bundle icicle) {
setContentView(R.layout.main);
/* This code together with the one in onDestroy()
* will make the screen be always on until this Activity gets destroyed. */
final PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
this.mWakeLock = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "My Tag");
this.mWakeLock.acquire();
}
#Override
public void onDestroy() {
this.mWakeLock.release();
super.onDestroy();
}
}
Don't forget to give permission in manifest file
<uses-permission android:name="android.permission.WAKE_LOCK" />

Application is being killed while on background

My application sends gps updates to a API. I need my application to run in background all the time. But unfortunately, my application always end at some point while on background. I have read that when the cpu usage of the application is low, the application is will be killed automatically. I don't want this to happen. I already included a partial wake lock on my onCreate method in my application using this code:
powerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "MyWakeLock");
Then on pause:
protected void onPause()
{
super.onPause();
onBackground = true;
wakeLock.acquire();
Log.w("OnPause", "OnPause");
}
I really don't know how to prevent my application being killed. I also tried using full wake lock but it is deprecated. Any ideas on how will I keep my application alive on background? I never want my application to be killed while on background. Thanks!

You can not.
Just make sure, you persist anything that should survive after being killed.
For anything that should run in background, even if the app is not shown to the user:
Use a Service and set it into foreground mode.

public class BGService extends Service {
private PowerManager powerManager;
private WakeLock wakeLock;
#Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
powerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
"MyWakeLock");
wakeLock.acquire();
}
call and start service in your main activity
public class SendSMSActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.demo);
startService(new Intent(this, BGService.class));
}
}

What should I do as power button do (turn off screen, lock keyboard)?

My goal is make same thing as power button do.
I try PARTIAL_WAKE_LOCK and this is my code..
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
wl.acquire();
after that I open WAKE_LOCK permission in AndroidManifest.xml
<uses-permission android:name="android.permission.WAKE_LOCK" />
But when I launch my application not thing happen.
Do I miss something ?
Thanks

From your question I'm not totally sure whether you:
Try to turn off the device by pressing a button
Want to make sure the device will not go to sleep (as this is what a WakeLock is supposed to help you with). It can't prevent user interaction though (just tested on HTC Desire).
For 1) You can't lock the device or turn it's power off without being signed as a system app, as written here: http://groups.google.com/group/android-developers/browse_thread/thread/36399f15724ac3ae/98d93e53616cf495?show_docid=98d93e53616cf495
For 2) You can prevent the device from sleeping using WakeLock, sample code can read like this:
/**
* Called when the activity is first created.
*/
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
wl = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK, TAG);
}
// Call me from a button
public void doLock(View view) {
Log.d(TAG, "Lock");
if (!wl.isHeld()) {
Log.d(TAG, "acquire");
wl.acquire();
} else {
Log.d(TAG, "release");
wl.release();
}
}