具有 Android 架构组件的 AppWidgetProvider

Question

我想用 AppWidgetProvider 实现 Android Architecture Component。

我不确定将 Widget LifeCycle 正确映射到 LifeCycle events。

我创建了一个 BaseAppWidgetProvider 以供我的小部件扩展：

/**
 * Base class for {@link BaseAppWidgetProvider} to manage {@link Lifecycle}
 */

public abstract class BaseAppWidgetProvider extends AppWidgetProvider implements LifecycleOwner {
    private final AppWidgetProviderLifecycleDispatcher mDispatcher = new AppWidgetProviderLifecycleDispatcher(this);

    public BaseAppWidgetProvider(){
        mDispatcher.onConstructor();
    }

    @CallSuper
    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        mDispatcher.onUpdate();
        super.onUpdate(context, appWidgetManager, appWidgetIds);
    }

    @CallSuper
    @Override
    public void onDeleted(Context context, int[] appWidgetIds) {
        mDispatcher.onDeleted();
        super.onDeleted(context, appWidgetIds);
    }

    @CallSuper
    @Override
    public void onEnabled(Context context) {
        mDispatcher.onEnabled();
        super.onEnabled(context);
    }

    @CallSuper
    @Override
    public void onDisabled(Context context) {
        mDispatcher.onDisabled();
        super.onDisabled(context);
    }

    @CallSuper
    @Override
    public void onRestored(Context context, int[] oldWidgetIds, int[] newWidgetIds) {
        mDispatcher.onRestored();
        super.onRestored(context, oldWidgetIds, newWidgetIds);
    }

    @CallSuper
    @Override
    public void onAppWidgetOptionsChanged(Context context, AppWidgetManager appWidgetManager, int appWidgetId, Bundle newOptions) {
        mDispatcher.onAppWidgetOptionsChanged();
        super.onAppWidgetOptionsChanged(context, appWidgetManager, appWidgetId, newOptions);
    }

    @NonNull
    @Override
    public Lifecycle getLifecycle() {
        return mDispatcher.getLifecycle();
    }
}

和调度员

public class AppWidgetProviderLifecycleDispatcher {
    private final LifecycleRegistry mRegistry;
    private final Handler mHandler;
    private DispatchRunnable mLastDispatchRunnable;


    /**
     * @param provider {@link LifecycleOwner} for a service, usually it is a service itself
     */
    public AppWidgetProviderLifecycleDispatcher(@NonNull LifecycleOwner provider) {
        mRegistry = new LifecycleRegistry(provider);
        mHandler = new Handler();
    }
    private void postDispatchRunnable(Lifecycle.Event event) {
        Timber.d("postDispatchRunnable event="+event);
        if (mLastDispatchRunnable != null) {
            mLastDispatchRunnable.run();
        }
        mLastDispatchRunnable = new DispatchRunnable(mRegistry, event);
        mHandler.postAtFrontOfQueue(mLastDispatchRunnable);
    }


    /**
     * Must be a first call in {@link android.appwidget.AppWidgetProvider#AppWidgetProvider()} constructor, even before super call.
     */
    public void onConstructor(){
        postDispatchRunnable(Lifecycle.Event.ON_CREATE);
        postDispatchRunnable(Lifecycle.Event.ON_START);
    }

    /**
     * Must be a first call in {@link android.appwidget.AppWidgetProvider#onDeleted(Context, int[])} method, even before super.onDeleted call.
     */
    public void onDeleted(){
        postDispatchRunnable(Lifecycle.Event.ON_PAUSE);
        postDispatchRunnable(Lifecycle.Event.ON_STOP);
        postDispatchRunnable(Lifecycle.Event.ON_DESTROY);
    }

    /**
     * Must be a first call in {@link android.appwidget.AppWidgetProvider#onDisabled(Context)} method, even before super.onDisabled call.
     */
    public void onDisabled(){
        postDispatchRunnable(Lifecycle.Event.ON_PAUSE);
        postDispatchRunnable(Lifecycle.Event.ON_STOP);
        postDispatchRunnable(Lifecycle.Event.ON_DESTROY);
    }

    /**
     * Must be a first call in {@link android.appwidget.AppWidgetProvider#onEnabled(Context)} method, even before super.onEnabled call.
     */
    public void onEnabled(){
        postDispatchRunnable(Lifecycle.Event.ON_CREATE);
        postDispatchRunnable(Lifecycle.Event.ON_START);
    }


    /**
     * Must be a first call in {@link android.appwidget.AppWidgetProvider#onRestored(Context, int[], int[])} method, even before super.onRestored call.
     */
    public void onRestored(){
        postDispatchRunnable(Lifecycle.Event.ON_CREATE);
        postDispatchRunnable(Lifecycle.Event.ON_START);
    }

    /**
     * Must be a first call in {@link android.appwidget.AppWidgetProvider#onUpdate(Context, AppWidgetManager, int[])} method, even before super.onUpdate call.
     */
    public void onUpdate(){
        postDispatchRunnable(Lifecycle.Event.ON_RESUME);
    }

    /**
     * @return {@link Lifecycle} for the given {@link LifecycleOwner}
     */
    public Lifecycle getLifecycle() {
        return mRegistry;
    }

    public void onAppWidgetOptionsChanged() {
        postDispatchRunnable(Lifecycle.Event.ON_RESUME);
    }

    static class DispatchRunnable implements Runnable {
        private final LifecycleRegistry mRegistry;
        final Lifecycle.Event mEvent;
        private boolean mWasExecuted = false;
        DispatchRunnable(@NonNull LifecycleRegistry registry, Lifecycle.Event event) {
            mRegistry = registry;
            mEvent = event;
        }
        @Override
        public void run() {
            if (!mWasExecuted) {
                mRegistry.handleLifecycleEvent(mEvent);
                mWasExecuted = true;
            }
        }
    }

}

Answer 1

AppWidgetProvider 是 BroadcastReceiver。它没有生命周期。您的 AppWidgetProvider 的一个实例仅适用于一个回调方法（例如，onUpdate()）。因此，没有到 Lifecycle 事件的映射，就像没有 Lifecycle 事件到普通 BrodadcastReceiver.

的映射一样