Develop Reference

OnePlus Nord devices with Android 10 are painful! 😔

We have an enterprise application being developed, and since the project inception, we're facing a constant crash only in OnePlus Nord devices.
We tried to reproduce in our devices, and it's not getting reproduced, but Firebase Crashlytics always reports it in live application. Description as:
cpe.java line 11
com.oneplus.theme.cpe.onViewAttachedToWindow
Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.removeOnAttachStateChangeListener(android.view.View$OnAttachStateChangeListener)' on a null object reference
at com.oneplus.theme.cpe.onViewAttachedToWindow(cpe.java:11)
at android.view.View.dispatchAttachedToWindow(View.java:20272)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3455)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2273)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1960)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8228)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1239)
at android.view.Choreographer.doCallbacks(Choreographer.java:1041)
at android.view.Choreographer.doFrame(Choreographer.java:953)
at android.view.Choreographer$FrameHandler.handleMessage(Choreographer.java:1163)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7711)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
At this stage, as it is working fine on all other devices, we couldn't pinpoint any code which could be causing this issue.
Being reported with many OnePlus Nord users, this issue brings our crash free % down significantly! How to fix this?

It's some view related problem I think.
It's saying that you're using listener on null view object. So check if you are getting the view first & then applying listener.
You can use GlobalLayoutListener to check if the view has finished Drawing.
yourView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
yourView.getViewTreeObserver()
.removeOnGlobalLayoutListener(this);
//Your logic here (You can Put the OnAttachStateChangeListener here)
}
});

onBackPressed sometimes or always called automaticaly when starting activity

i have problem with my app in some devices (HUAWEI P10 Lite, rockchip A95XR3). Maybe more in future.
According to users, when opening the Video Player Activity, the app immediately crashes.
I think, when they open the Video Player Activity, they quickly press the back button when Activity is not ready. So I tried to use my Oppo Realme 5Pro device and then tried to hit the back button with lightning speed, but it didn't crash (I tried several times). And I also tried running it on the emulator according to the Android version with problems 8.0.0 and 9.
Stack Trace:
Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'void c.d.b.a.t0.b()' on a null object reference
at com.**cencored**.C_Video_Player.ReleasePlayer(Act_Video_Player.java:163)
at com.**cencored**.C_Video_Player.onBackPressed(Act_Video_Player.java:405)
at android.app.Activity.onKeyUp(Activity.java:3161)
at android.view.KeyEvent.dispatch(KeyEvent.java:2779)
at androidx.core.view.KeyEventDispatcher.activitySuperDispatchKeyEventPre28(KeyEventDispatcher.java:137)
at androidx.core.view.KeyEventDispatcher.dispatchKeyEvent(KeyEventDispatcher.java:87)
at androidx.core.app.ComponentActivity.dispatchKeyEvent(ComponentActivity.java:133)
at androidx.appcompat.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:558)
at androidx.appcompat.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
at androidx.appcompat.app.AppCompatDelegateImpl$AppCompatWindowCallback.dispatchKeyEvent(AppCompatDelegateImpl.java:2814)
at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:415)
at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:5191)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5063)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4581)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4634)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4600)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4727)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4608)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4784)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4581)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4634)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4600)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4608)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4581)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4634)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4600)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4760)
at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:4921)
at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:2599)
at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:2160)
at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:2151)
at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:2574)
at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141)
at android.os.MessageQueue.nativePollOnce(MessageQueue.java)
at android.os.MessageQueue.next(MessageQueue.java:379)
at android.os.Looper.loop(Looper.java:144)
at android.app.ActivityThread.main(ActivityThread.java:7523)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)
If I see Stack Trace through Firebase Crashlytics, it looks like onBackPressed has been called, but according to the user they don't press the back button.
Below this is part of the code that is related to the problem.
private void ReleasePlayer() {
exoPlayer.release(); //Line 163
isVideoPrepared ="no";
TextError.setVisibility(GONE);
TextReconnecting.setVisibility(GONE);
TextTryCount.setVisibility(GONE);
}
#Override
public void onBackPressed() {
super.onBackPressed();
exoPlayerView.setVisibility(GONE);
forInfo.setVisibility(GONE);
forAds.setVisibility(GONE);
forControl.setVisibility(GONE);
ReleasePlayer(); //Line 405
finish();
}
On the stack trace above also not mentioned onCreate, so of course the exoplayer has not been initialized yet.
The real question is, what are the problems with the above devices? or maybe in my code?

Error after updating targetSDK version - ListView not working: interface method 'int java.util.List.size()' on a null object reference

I have a NameDay app in the App Store that was using an Android SDK <26. Since Google wants to make every app change its TargetSDK at least to 26 in order to continue being able to update, I wanted to change my app in order to satisfy Google's needs.
Changed the proper fields regarding the SDK, but now I get a crash when I try to run the app in the emulator.
App MainActivity:
The main activity of the app searches the database and gets all the names that celebrate today and shows them. Below that textview, i have a listview that compares the names that celebrate today to your contacts, and shows the contacts celebrating their name day in order to be able to call or send an sms.
The error I get is:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.duk3r.eortologio2, PID: 9577
java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
at com.duk3r.eortologio2.LazyAdapter.getCount(LazyAdapter.java:32)
at android.widget.AdapterView$AdapterDataSetObserver.onChanged(AdapterView.java:836)
at android.widget.AbsListView$AdapterDataSetObserver.onChanged(AbsListView.java:6414)
at android.database.DataSetObservable.notifyChanged(DataSetObservable.java:37)
at android.widget.BaseAdapter.notifyDataSetChanged(BaseAdapter.java:50)
at com.duk3r.eortologio2.LazyAdapter.setItems(LazyAdapter.java:45)
at com.duk3r.eortologio2.MainActivity$LoadItemsTask.onPostExecute(MainActivity.java:498)
at com.duk3r.eortologio2.MainActivity$LoadItemsTask.onPostExecute(MainActivity.java:480)
at android.os.AsyncTask.finish(AsyncTask.java:695)
at android.os.AsyncTask.-wrap1(Unknown Source:0)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:712)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6541)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
The main files that appear in the error messages are:
MainActivity.java
and LazyAdapter.java
I read similar posts here in StackOverflow and they say that getCount() returns null and crashes the app. The thing is that I didn't change and code regarding the adapters or/and the main activity, and the app was working before. Did Google change something in the latest SDKs?
Thanks in advance.
Update: The app works fine with targetSDK 27 in an emulator with API 23, just tried it again. When I switch to an emulator with SDK >26, it crashes on startup when it tries to check the listview code.

It seems that the problem was that from API 23 and forth, the declared permissions in the Android Manifest don't really matter. You have to ask for the permissions on the fly, if you want it to work on api >23.
Made it work with this:
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP_MR1) {
if (checkSelfPermission(Manifest.permission.READ_CONTACTS) ==
PackageManager.PERMISSION_GRANTED) {
System.out.println("Permission Granted");
} else {
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.READ_CONTACTS},
MY_PERMISSIONS_REQUEST_READ_CONTACTS);
}
}
You have to ask for each permission you need separately, so that the app continues to work with no problem.

java.lang.NullPointerException IntentService

I'm trying to start a service in a different app that's installed on the device. I get a NullPointerException when using startService
public void notConnected(){
Log.i(TAG,"no connection... reconnecting.");
Intent reset = new Intent("com.famoco.intent.action.TOGGLE_DATA");
Log.i(TAG,"calling " + reset.getAction());
if(reset.getAction().equals("com.famoco.intent.action.TOGGLE_DATA"))
{
startService(reset);
}
else
{
Log.i(TAG,"couldn't start service");
}
}
and this is error log
E/AndroidRuntime: FATAL EXCEPTION: IntentService[MyAppCommService]
Process: com.myapppackage.MyApp, PID: 8583
java.lang.NullPointerException
at android.content.ContextWrapper.startService(ContextWrapper.java:494)
at com.myapppackage.MyApplocation.activity.MyAppActivity.notConnected(MyAppActivity.java:591)
at com.myapppackage.MyApplocation.api.MyAppApi.submitClock(MyAppApi.java:228)
at com.myapppackage.MyApplocation.service.MyAppCommService.submitTags(MyAppCommService.java:52)
at com.myapppackage.MyApplocation.service.MyAppCommService.onHandleIntent(MyAppCommService.java:98)
at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.os.HandlerThread.run(HandlerThread.java:61)
Turns out my context returned null, I fixed it by getting the context in onCreate and calling myContext.startservice.

You are starting a new Intent. And looking at that Google example, looks like you use the wrong method to start it up.
- you use:
startService(reset);
- try this one:
startActivity(intent);
But that starts an Activity. And you want an service. I don't think you can do that unless you are the developer of that other app. In general, Android Apps don't have access each others code & resources.

Fixed it by returning context in the onCreate() and then calling context.startService()

Android Wear Watchface and the WakeLock

I'm developing a watchface for Android Wear using the WatchFace API (extending CanvasWatchFaceService).
I've used the code from here to build a ticker that run code every second.
I'm experiencing the following problem. Every now and then the service crashes with this exception. I can't understand where it comes from, if you have any lead I'll post additional code.
01-06 11:22:00.247 12965-12965/com.my.package E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.my.package, PID: 12965
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.os.PowerManager$WakeLock.acquire()' on a null object reference
at android.support.wearable.watchface.WatchFaceService$Engine.onCommand(WatchFaceService.java:201)
at android.service.wallpaper.WallpaperService$Engine.doCommand(WallpaperService.java:977)
at android.service.wallpaper.WallpaperService$IWallpaperEngineWrapper.executeMessage(WallpaperService.java:1191)
at com.android.internal.os.HandlerCaller$MyHandler.handleMessage(HandlerCaller.java:37)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
After this crash the watchface stops working and to make it start again I have to choose another watchface, then reselect mine, so it's a total show stopper!

Props to David for the lead on super. calls - it turns out that was the problem. Specifically, the CanvasWatchFaceService.Engine.onCreate method needs to call through to its ancestor, as such:
private class Engine extends CanvasWatchFaceService.Engine {
#Override
public void onCreate(SurfaceHolder holder) {
super.onCreate(holder);
// your engine initialization code here
}
// other watch face engine code
}
Without the super.onCreate(holder); call, my watch face would crash within minutes; with it, it happily ran overnight.
As an aside, this is something missing from the Android developer documentation; specifically, the Training page for Building a Watch Face Service doesn't include this ancestor call in its code sample.

The code you linked lacks some important parts, that are dotted. I.e. have you defined the update rate?
private static final long INTERACTIVE_UPDATE_RATE_MS = TimeUnit.SECONDS.toMillis(1);
Fully implemented it works well. See AnalogWatchFaceService in code samples: Wearable/Watchface face.