Develop Reference

To detect the screenlock even when the app is sleeping

I have an android application that needs to be locked (redirect to the login page) whenever the user presses the lock button. The user can lock the phone while on my application or while on other applications/home screen. In both of these scenarios, I need my application to be locked.
This is working fine in case the phone is locked from an application :
#Override
protected void onStop() {
super.onStop();
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
boolean isScreenOn = pm.isInteractive();
if (!isScreenOn) {
LogUtils.logD(TAG, "Screen is off, Locking the application");
// Lock the application code
}
}
But I am not able to figure out the second scenario when the user has moved away from the application and then locks it. I do not want to start a service or any background thread for this purpose.

Try to add else and return at the end of the code so the activity will still awake in background process
#Override
protected void onStop() {
super.onStop();
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
boolean isScreenOn = pm.isInteractive();
if (!isScreenOn) {
LogUtils.logD(TAG, "Screen is off, Locking the application");
// Lock the application code
} else{
return true;
}

Stop the lock screen for a while if possible

I want to override the lock screen button somehow. The idea is that I want to keep my screen awake for a while, and I did so
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
PowerManager.WakeLock wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
"MyWakelockTag");
wakeLock.acquire();
}
Anyway, I have a flip cover on my phone, and when I put the flip on, my phone is get locked. How could I stop the locking screen event when I put the flip cover on? That's why I need to know if it's possible to stop the lock screen functionality for a while.

For the Flipcover, you have to check the SensorManager and for the Power/Lock Button you can try this -
public class ScreenReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
switch (action) {
case Intent.ACTION_SCREEN_OFF:
BaseActivity.unlockScreen();
break;
case Intent.ACTION_SCREEN_ON:
// and do whatever you need to do here
BaseActivity.clearScreen();
}
}
}
But I'm not sure it'll work

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));
}
}

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

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();
}
}