RxAndroid：Schedulers.io() 线程上的 UI 更改

我在 IO 线程上有一个简单的工作，即更改主屏幕壁纸，之后我尝试在 UI 线程上运行一些动画：

     AppObservable.bindFragment(this, Observable.just(0))
       .observeOn(Schedulers.io())
       .subscribe(v -> setWallpaperOnSeparateThread());

private void setWallpaperOnSeparateThread() {
     WallpaperHelper.setBitmapAsWallpaper(photoViewAttacher.getVisibleRectangleBitmap(), getBaseActivity());

     AppObservable.bindFragment(this, Observable.just(0))
       .delay(500, TimeUnit.MILLISECONDS)
       .observeOn(AndroidSchedulers.mainThread())
       .subscribe(integer -> loadFinishAnimationAfterSetWallpaper());
}

但这种方法会导致错误：java.lang.IllegalStateException: Observers must subscribe from the main UI thread, but was Thread[RxCachedThreadScheduler-1,5,main]

我尝试将第二个 Observable 更改为：

  AppObservable.bindFragment(this, Observable.just(0))
    .delay(2000, TimeUnit.MILLISECONDS)
    .observeOn(Schedulers.io())
    .subscribeOn(AndroidSchedulers.mainThread())
    .subscribe(integer -> loadFinishAnimationAfterSetWallpaper());

但这没有帮助。

AppObservable.bindFragment(this, Observable.just(0))抛出异常，因为它不是从主线程调用的

该代码不会在主线程中调用，因为您观察到Schedulers.io在此代码中（见下文），比后一个调用AppObservable.bindFragment(this, Observable.just(0))

AppObservable.bindFragment(this, Observable.just(0))
   .observeOn(Schedulers.io())
   .subscribe(v -> setWallpaperOnSeparateThread());

您想要在 io 线程中执行任务，然后在主线程中执行任务。为此，您可以使用一个链接调用Observable.

AppObservable.bindFragment(this, Observable.just(0))
   .observeOn(Schedulers.io())
   .flatMap(v -> Observable.defer(() -> WallpaperHelper.setBitmapAsWallpaper(photoViewAttacher.getVisibleRectangleBitmap(), getBaseActivity())))
   .delay(500, TimeUnit.MILLISECONDS)
   .observeOn(AndroidSchedulers.mainThread())
   .subscribe(v -> loadFinishAnimationAfterSetWallpaper());

请注意我使用defer将您的异步任务表示为Observable但你可以更换flatMap打电话给doOnNext call.

AppObservable.bindFragment(this, Observable.just(0))
   .observeOn(Schedulers.io())
   .doOnNext(v -> WallpaperHelper.setBitmapAsWallpaper(photoViewAttacher.getVisibleRectangleBitmap(), getBaseActivity()))
   .delay(500, TimeUnit.MILLISECONDS)
   .observeOn(AndroidSchedulers.mainThread())
   .subscribe(v -> loadFinishAnimationAfterSetWallpaper());