Develop Reference

Activity does not start until the screen is turned on

My service starts an Activity like this:
Intent intent = new Intent(context, CallMonitor.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
this happens in CallMonitor.onCreate():
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
On most devices, the activity (called up from service) wakes up the device, turns on the screen and is displayed.
But - for example - on Galaxy Tab 4, the activity is only called if the screen is already switched on.
If the screen is switched off and the service calls up the activity, it is displayed with a delay - It will be displayed immediatly after turning the screen on.
There is also a voice output in the activity. When the Galaxy S4 is switched off, it will not be played back - but immediatly after turning the screen on again.
Any suggestions?
I don't want to use WakeLock!

It looks like that's a device limitation and I don't know how you could work around that without using a WakeLock. We have a really old piece of code which you could modify to your needs which pretty much always worked for us:
public static void bringToFront() {
try {
PowerManager pm = (PowerManager) MainActivity.getAppContext().getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP | PowerManager.ON_AFTER_RELEASE, "ALARM");
wl.acquire();
KeyguardManager keyguardManager = (KeyguardManager) MainActivity.getAppContext().getSystemService(Activity.KEYGUARD_SERVICE);
KeyguardManager.KeyguardLock lock = keyguardManager.newKeyguardLock(KEYGUARD_SERVICE);
lock.disableKeyguard();
if (MainActivity.getAppActivity() != null) {
MainActivity.getAppActivity().getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
}
} catch(Exception e){
e.printStackTrace();
Log.w(TAG, "bringToFront Err: "+e.toString());
}
}

Android app launches on opening lockscreen

I want my app or a part (any activity) of the app to be launched on opening the lockscreen, i.e, when we unlock the keypad of our phone, my activity should start running.. Thanks in advance. :D enter image description here

Try this one
A way to get unlock event in android?
It's using ACTION_USER_PRESENT receiver, but stil could help you.

To unlock the keyguard.
add this permission <uses-permission android:name="android.permission.DISABLE_KEYGUARD" />
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
// createWakeLocks();
KeyguardManager kgm = (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);
boolean isKeyguardUp = kgm.inKeyguardRestrictedInputMode();
KeyguardLock kgl = kgm.newKeyguardLock("QuickPopup");
if (isKeyguardUp) {
kgl.disableKeyguard();
isKeyguardUp = false;
}
getWindow().addFlags(
WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
getWindow().addFlags(
WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
// getWindow()
// .addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
getWindow()
.addFlags(WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
//wakeDevice();
}

Check whether onPause state of activity is called due to screen lock

If my app is running and I press lock screen button, it will put the app in background.What is the method to check whether onPause() is called by screen lock?.Thanks in advance.

All you have to do is check if the screen is on or not.
#Override
protected void onPause() {
super.onPause();
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
boolean screenOn;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) {
screenOn = pm.isInteractive();
} else {
screenOn = pm.isScreenOn();
}
if (screenOn) {
// Screen is still on, so do your thing here
}
}

You Can Simply Know It By Using This Method
#Override
public void onPause() {
super.onPause(); // Always call the superclass method first
System.out.println("On Pause called");
}
For Keeping The Device Awake while lock screen. Documentation.
Ok in your case you would need Wake_Lock
To use a wake lock, the first step is to add the WAKE_LOCK permission to your application's manifest file:
<uses-permission android:name="android.permission.WAKE_LOCK" />
If your app includes a broadcast receiver that uses a service to do some work, you can manage your wake lock through a WakefulBroadcastReceiver, as described in Using a WakefulBroadcastReceiver. This is the preferred approach. If your app doesn't follow that pattern, here is how you set a wake lock directly:
PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
Wakelock wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
"MyWakelockTag");
wakeLock.acquire();
To release the wake lock, call wakelock.release(). This releases your claim to the CPU. It's important to release a wake lock as soon as your app is finished using it to avoid draining the battery.
DO this after setting powermanager.
boolean screenOn;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) {
screenOn = powerManager.isInteractive();
} else {
screenOn = powerManager.isScreenOn();
}
if (screenOn) {
// Screen is still on, so do your thing here
}

You just want to know when onPause is called? You could override the super function and add logging to the function:
#Override
public void onPause() {
super.onPause();
System.out.println("On Pause called");
}

How to lock a device in android

How to lock a android device or screen??. Here is my code.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
context = this;
Button b = new Button(context);
b = (Button)findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
System.out.println("inside button");
PowerManager pManager = (PowerManager)
getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pManager.newWakeLock(PowerManager.
PARTIAL_WAKE_LOCK, "lock screen");
wl.acquire();
wl.release();
}
});
}
Here I am using a button. when user clicks on then the screen should be lock. But this code is not working. Is have to use BraodCastRecievr??. I included this permmission in manifest
<uses-permission android:name="android.permission.WAKE_LOCK" />
But also not working

KeyguardManager keyguardManager = (KeyguardManager)getSystemService(Activity.KEYGUARD_SERVICE);
KeyguardLock lock = keyguardManager.newKeyguardLock(KEYGUARD_SERVICE);
For locking the screen use,
lock.reenableKeyguard();
and for disabling the lock use,
lock.disableKeyguard()
This will just hide the lock screen and will display if any incoming call or any such event is happening, it will display that screen. It wont display the lock screen.
When running the application, to disable from going to the lock state, just use
setKeepScreenOn() is set to true. or use the xml attribute android:keepScreenOn="true"
Another way to prevent the device to go to the sleep or lock mode when the application is running is set this api to true - setKeepScreenOn()
And of course we need to give permission android.permission.DISABLE_KEYGUARD

Try out the example shown here:
http://developer.android.com/reference/android/os/PowerManager.html
Lock the android device programmatically

Wake Android Device up

Hey i need to wake my sleeping android device up at a certain time.
Any suggestions?
P.S. Wake up: turn display on and maybe unlock phone

To wake up the screen:
PowerManager pm = (PowerManager) getApplicationContext().getSystemService(Context.POWER_SERVICE);
WakeLock wakeLock = pm.newWakeLock((PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.FULL_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP), "TAG");
wakeLock.acquire();
To release the screen lock:
KeyguardManager keyguardManager = (KeyguardManager) getApplicationContext().getSystemService(Context.KEYGUARD_SERVICE);
KeyguardLock keyguardLock = keyguardManager.newKeyguardLock("TAG");
keyguardLock.disableKeyguard();
And the manifest needs to contain:
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.DISABLE_KEYGUARD" />
For more details about PowerManager, refer to the API documentation: http://developer.android.com/reference/android/os/PowerManager.html
EDIT: this answer is reported as deprecated.

Best is to use some appropriate combination of these window flags:
http://developer.android.com/reference/android/view/WindowManager.LayoutParams.html#FLAG_DISMISS_KEYGUARD
http://developer.android.com/reference/android/view/WindowManager.LayoutParams.html#FLAG_SHOW_WHEN_LOCKED
http://developer.android.com/reference/android/view/WindowManager.LayoutParams.html#FLAG_KEEP_SCREEN_ON
http://developer.android.com/reference/android/view/WindowManager.LayoutParams.html#FLAG_TURN_SCREEN_ON
If you want to run on older versions of the platform that don't support the desired flag(s), you can directly use wake locks and keyguard locks... but that path is fraught with peril.
ONE IMPORTANT NOTE: Your activity must be full screen in order for the above flag combination to work. In my app I tried to use these flags with an activity which is not full screen (Dialog Theme) and it didn't work. After looking at the documentation I found that these flags require the window to be a full screen window.

I found a way and it is not that complex... works on any API version.
You need to use PowerManager.userActivity(l, false) method and register your activity as broadcast received for SCREEN_OFF intent:
In your actiivity OnCreate put something like:
mReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Log.v(TAG, "Screen OFF onReceive()");
screenOFFHandler.sendEmptyMessageDelayed(0, 2000L);
}
};
It will kick off the handler after 2 seconds of Screen Off event.
Register receiver in your onResume() method:
IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_OFF);
registerReceiver(mReceiver, filter);
Log.i(TAG, "broadcast receiver registered!");
Create a handler like the one below:
private Handler screenOFFHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
// do something
// wake up phone
Log.i(TAG, "ake up the phone and disable keyguard");
PowerManager powerManager = (PowerManager) YourActivityName.this
.getSystemService(Context.POWER_SERVICE);
long l = SystemClock.uptimeMillis();
powerManager.userActivity(l, false);//false will bring the screen back as bright as it was, true - will dim it
}
};
Request permission in your manifest file:
<uses-permission android:name="android.permission.WAKE_LOCK" />
Do not forget to unregister broadcast receiver when you are done. You may do that in onDestroy() for example (which is not guaranteed)
unregisterReceiver(mReceiver);
Log.i(TAG, "broadcast UNregistred!");

On newer devices you should use something like this, since the mentioned Flags are deprecated.
class AlarmActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_alarm)
// Keep screen always on, unless the user interacts (wakes the mess up...)
window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
setTurnScreenOn(true)
setShowWhenLocked(true)
(getSystemService(KeyguardManager::class.java) as KeyguardManager).requestDismissKeyguard(this,
object: KeyguardManager.KeyguardDismissCallback(){
override fun onDismissCancelled() {
Log.d("Keyguard", "Cancelled")
}
override fun onDismissError() {
Log.d("Keyguard", "Error")
}
override fun onDismissSucceeded() {
Log.d("Keyguard", "Success")
}
}
)
}
}
KeyguardManager.requestDismissKeyguard only wakes up the device, if the setter setTurnScreenOn(true) was called before.
I tested this on my Android Pie device.

Try with the below code after setContentView(R.layout.YOUR_LAYOUT); in activity onCreate() method
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
Log.d(TAG, "onCreate: set window flags for API level > 27");
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN
| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
KeyguardManager keyguardManager = (KeyguardManager) getApplicationContext().getSystemService(Context.KEYGUARD_SERVICE);
keyguardManager.requestDismissKeyguard(this, null);
setShowWhenLocked(true);
setTurnScreenOn(true);
} else {
Log.d(TAG, "onCreate: onCreate:set window flags for API level < 27");
getWindow().addFlags(
WindowManager.LayoutParams.FLAG_FULLSCREEN
| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
| WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
| WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
| WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
}

If you are showing a window when waking up, you can get it working easily by adding few flags to your activity, without using a wake lock.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
}

Settling an alarm programatically will wake up the phone(play a sound) and i guess the turn on display would be an option there.
I donot think there would be an exposed API that will unlock the phone automatically.

getWindow().addFlags(LayoutParams.FLAG_DISMISS_KEYGUARD);
will dismiss the general keyguard and cause the device to unlock.