App crashes if user presses back button when ImageActivity is gone

[prfarlow1]

Example Code that causes crash:

    private void showAvatarImagePicker() {
        ImagePicker.Builder builder = new ImagePicker.Builder(getActivity())
                .mode(ImagePicker.Mode.CAMERA_AND_GALLERY)
                .compressLevel(ImagePicker.ComperesLevel.NONE)
                .directory(ImagePicker.Directory.DEFAULT)
                .extension(ImagePicker.Extension.JPG)
                .scale(344, 344)
                .allowMultipleImages(false)
                .enableDebuggingMode(true);
        imagePickDisposable.dispose();
        imagePickDisposable = new ImagePickerHelper(builder).getObservable()
                .subscribe(data -> {
                    updateUiWithImage(date)
                }, throwable -> logger.error("error while picking an image", throwable));
    }

Crash log:

Fatal Exception: io.reactivex.exceptions.UndeliverableException: java.lang.Throwable: user did not select any image
       at io.reactivex.plugins.RxJavaPlugins.onError + 367(RxJavaPlugins.java:367)
       at io.reactivex.internal.operators.observable.ObservableCreate$CreateEmitter.onError + 74(ObservableCreate.java:74)
       at net.alhazmy13.mediapicker.rxjava.image.ImagePickerReceiver.onReceive + 35(ImagePickerReceiver.java:35)
       at android.app.LoadedApk$ReceiverDispatcher$Args.lambda$getRunnable$0 + 1487(LoadedApk.java:1487)
       at android.app.-$$Lambda$LoadedApk$ReceiverDispatcher$Args$_BumDX2UKsnxLVrE6UJsJZkotuA.run + 2(-.java:2)
       at android.os.Handler.handleCallback + 873(Handler.java:873)
       at android.os.Handler.dispatchMessage + 99(Handler.java:99)
       at android.os.Looper.loop + 216(Looper.java:216)
       at android.app.ActivityThread.main + 7263(ActivityThread.java:7263)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run + 494(RuntimeInit.java:494)
       at com.android.internal.os.ZygoteInit.main + 975(ZygoteInit.java:975)

Caused by java.lang.Throwable: user did not select any image
       at net.alhazmy13.mediapicker.rxjava.image.ImagePickerReceiver.onReceive + 35(ImagePickerReceiver.java:35)
       at android.app.LoadedApk$ReceiverDispatcher$Args.lambda$getRunnable$0 + 1487(LoadedApk.java:1487)
       at android.app.-$$Lambda$LoadedApk$ReceiverDispatcher$Args$_BumDX2UKsnxLVrE6UJsJZkotuA.run + 2(-.java:2)
       at android.os.Handler.handleCallback + 873(Handler.java:873)
       at android.os.Handler.dispatchMessage + 99(Handler.java:99)
       at android.os.Looper.loop + 216(Looper.java:216)
       at android.app.ActivityThread.main + 7263(ActivityThread.java:7263)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run + 494(RuntimeInit.java:494)
       at com.android.internal.os.ZygoteInit.main + 975(ZygoteInit.java:975)

Steps to reproduce: (1) In developers options on phone, enable the 'Don't keep activities' flag (2) Launch app on phone with ImagePickerHelper code above (3) Select either Gallery or Camera when prompted for image source (4) Press the back button (5) Observe app crashes

Fix: In ImagePickerObservable, add this line in the subscribe method:

emitter.setDisposable(Disposables.fromAction(() -> dispose()));