我是架构组件的新手，我已经创建了一个 ViewModel 类并根据架构组件实现 LifecycleObserver，在 ViewModel 类中我有一个可运行接口的覆盖 run() 方法，并在处理程序类的帮助下延迟递归调用它，在这个值图像数组内部发生变化并被实时数据包装。
MainActivity 观察图像数组的变化，随着值的变化，ImageView 绑定图像数组的值。主活动也是生命周期的所有者。
现在我想实现生命周期观察者，这样当我暂停我的应用程序时，run() 方法也应该暂停，当我恢复应用程序时，它从我暂停的地方开始。
我通过在处理程序中创建暂停和恢复方法来尝试它，但它不起作用。
帮我解决这个问题。
MainActivity 类
private ImageViewModel imageViewModel;
private ImageView imageView;
private ProgressBar progressBar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
showDialogueBox();
}
private void showDialogueBox() {
final Dialog dialog = new Dialog(MainActivity.this);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.dialogue_box);
dialog.setTitle("custom");
Button button =(Button)dialog.findViewById(R.id.button1);
button.setEnabled(true);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
imageViewModel = ViewModelProviders.of(MainActivity.this).get(ImageViewModel.class);
subscribe();
dialog.cancel();
}
});
dialog.show();
}
private void subscribe() {
final Observer<Integer> imageTimeObserver = new Observer<Integer>() {
@Override
public void onChanged(@Nullable Integer integer) {
imageView = findViewById(R.id.imageView);
imageView.setImageResource(integer);
getLifecycle().addObserver(new BrainalyseComponent(MainActivity.this,getApplicationContext(),imageViewModel));
}
};
final Observer<Integer> progressbarTimeObserver = new Observer<Integer>() {
@Override
public void onChanged(@Nullable Integer integer) {
progressBar = findViewById(R.id.progressBar);
progressBar.setProgress(integer);
}
};
imageViewModel.getImage().observe(this,imageTimeObserver);
imageViewModel.getProgressbarStatus().observe(this,progressbarTimeObserver);
}
视图模型类
private int imagesIndex;
private int delay;
public Handler handler;
private MutableLiveData<Integer> imageLiveData = new MutableLiveData<>();
private MutableLiveData<Integer> progressbarLiveData = new MutableLiveData<>();
private int progressBarStatus;
private HashMap<Integer,Integer> imagesAndDelay;
private int images[] =
{
R.drawable.food_1,
R.drawable.food_2,
R.drawable.food_3,
R.drawable.food_4,
R.drawable.food_5,
R.drawable.food_6,
R.drawable.food_7,
R.drawable.food_8,
R.drawable.food_9,
R.drawable.food_10
};
public ImageViewModel(){
imagesIndex = 0;
progressBarStatus = 0;
delay = 2;//to be changed as delay will be discussed
handler = new Handler();
imagesAndDelay = new HashMap<>();
shuffleImages();
runnable.run();
}
private void shuffleImages() {
Random random = new Random();
for (int i = 0; i < images.length; i++) {
int j = random.nextInt(images.length);
int temp = images[i];
images[i] = images[j];
images[j] = temp;
}
}
public Runnable runnable = new Runnable() {
@Override
public void run() {
if (imagesIndex<images.length){
progressBarStatus += 100/images.length;
progressbarLiveData.postValue(progressBarStatus);
imageLiveData.postValue(images[imagesIndex]);
imagesAndDelay.put(images[imagesIndex],delay);
imagesIndex++;
delay += 2;
}else {
stopTask();
return;
}
handler.postDelayed(runnable,2000);
}
};
public Thread newThread = new Thread(){
public void run(){
if (imagesIndex<images.length){
progressBarStatus += 100/images.length;
progressbarLiveData.postValue(progressBarStatus);
imageLiveData.postValue(images[imagesIndex]);
imagesAndDelay.put(images[imagesIndex],delay);
imagesIndex++;
delay += 2;
}else {
stopTask();
return;
}
try {
sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
run();
}
}
};
public LiveData<Integer> getImage(){
return imageLiveData;
}
public LiveData<Integer> getProgressbarStatus(){
return progressbarLiveData;
}
private void stopTask() {
delay = 2;
progressBarStatus = 0;
imagesIndex = 0;
Utility.setImagesAndDelay(imagesAndDelay);
handler.removeCallbacks(runnable);
}
生命周期观察者
private Context mContext;
private static final String LOG_TAG = BrainalyseComponent.class.getSimpleName();
private ImageView imageView;
private ProgressBar progressBar;
private Integer integer;
LifecycleOwner lifecycleOwner;
private ImageViewModel imageViewModel;
public BrainalyseComponent(LifecycleOwner lifecycleOwner, Context context, ImageViewModel imageViewModel) {
this.mContext = context;
this.imageView = imageView;
this.imageViewModel = imageViewModel;
this.integer = integer;
this.progressBar = progressBar;
this.lifecycleOwner = lifecycleOwner;
}
@OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
public void onResume(){
Log.d(LOG_TAG,"on resume of app");
}
@OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
public void onPause(){
}