RxJava2.0异步线程实现Handler功能，AsyncTask实现Handler功能

最新推荐文章于 2023-04-11 15:59:03 发布

原创最新推荐文章于 2023-04-11 15:59:03 发布 · 138 阅读

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#android

该文展示了如何使用RxJava2.0的Observable和AsyncTask来实现类似Handler的异步处理功能，具体是通过Picasso库加载图片到Drawable，然后在主线程更新UI。在RxJava示例中，创建了一个Observable，使用Schedulers.io()和AndroidSchedulers.mainThread()切换线程，最后将Drawable传递给订阅者更新UI。在AsyncTask示例中，图片加载和处理在后台线程执行，完成后在onPostExecute()回调中更新UI。

RxJava2.0异步线程实现Handler功能

Observable.create(new ObservableOnSubscribe<Drawable>() {
    @Override
    public void subscribe(ObservableEmitter<Drawable> emitter) throws Exception {
        Bitmap normalBitmap = Picasso.with(context).load(bean.getIcon_url()).get();
        Bitmap selectedBitmap = Picasso.with(context).load(bean.getIcon_hl_url()).get();
        Drawable drawable = SelectorUtils.generatePressedSelector(new BitmapDrawable(selectedBitmap), new BitmapDrawable(normalBitmap));
        Logger.d(TAG, "After observeOn(io), current thread is: " + Thread.currentThread().getName());
        emitter.onNext(drawable);
    }
}).subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Consumer<Drawable>(){
            @Override
            public void accept(Drawable drawable) throws Exception {
                Logger.d(TAG, "After observeOn(mainThread), current thread is : " + Thread.currentThread().getName());
                holder.menuImg.setImageDrawable(drawable);
            }
        });

AsyncTask实现Handler功能

new AsyncTask<Void,Void,Drawable>(){
    @Override
    protected Drawable doInBackground(Void... voids) {
        try {
            Bitmap normalBitmap = Picasso.with(context).load(bean.getIcon_url()).get();
            Bitmap selectedBitmap = Picasso.with(context).load(bean.getIcon_hl_url()).get();
            Drawable drawable = SelectorUtils.generatePressedSelector(new BitmapDrawable(selectedBitmap), new BitmapDrawable(normalBitmap));
            return drawable;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Drawable drawable) {
        super.onPostExecute(drawable);
        holder.menuImg.setImageDrawable(drawable);
    }
}.execute();