okhttp3 使用 glide 异步加载图片时抛出 NetworkOnMainThreadException

Question

我正在尝试像这样将图像异步加载到 Leanback 中的 CardPresenter。

public interface CustomImageModel {  
    String requestCustomUrl(int width, int height);
}

public static class CustomImageModelGrabber implements CustomImageModel {

    public CustomImageModelGrabber() {

    }

    @Override
    public String requestCustomUrl(int width, int height) {
        OkHttpClient client = new OkHttpClient;
        Request request = new Request.Builder().url(image_url).build();
        return client.newCall(request).execute().body().string();
    }
}

public static class CustomImageUrlLoader extends BaseGlideUrlLoader<CustomImageModel> {  
    public CustomImageUrlLoader(Context context) {
        super( context );
    }

    @Override
    protected String getUrl(CustomImageModel model, int width, int height) {
        return model.requestCustomUrl();
    }
}

在CardPresenter.java

@Override
public void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) {

    CustomImageModel customImageRequest = new CustomImageModelGrabber();

    Glide  
            .with( context )
            .using( new CustomImageUrlLoader( context ) )
            .load( customImageRequest )
            .into( imageView1 );
}

不幸的是，这没有按预期工作。 只有少数图片被正确加载到卡片展示器中，但大部分都没有，并抛出以下错误：

android.os.NetworkOnMainThreadException
android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1303)

哪些有效哪些无效完全是随机的。

我也试过在MainActivity.java中设置严格模式。

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

虽然此解决方案可以正确加载所有图像并且不会引发任何 NetworkOnMainThreadException 错误，但它会带来巨大的性能问题。滚动变得缓慢和滞后，显示以下消息：

I/Choreographer: Skipped 182 frames!  The application may be doing too much work on its main thread.

有什么解决方案可以让图片异步加载，同时保持流畅和良好的性能吗？

Answer 1

我的做法是完全错误的。我以为 BaseGlideUrlLoader 在后台线程上运行，但事实并非如此。

所以要执行的代码如下：

@Override
public void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) {

    final ImageCardView cardView = (ImageCardView) viewHolder.view;

    OkHttpClient client = new OkHttpClient;
    Request request = new Request.Builder().url(image_url).build();


    client.newCall(request).enqueue(new Callback() {
      @Override public void onFailure(Call call, IOException e) {
        e.printStackTrace();
      }

      @Override public void onResponse(Call call, Response response) throws IOException {
        try (ResponseBody responseBody = response.body()) {
            if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);


            String imageFromResponse = responseBody.string();
            // do whatever is needed to get the image (i.e JSON-handling)

            Handler mainHandler = new Handler(Looper.getMainLooper());
            Runnable myRunnable = new Runnable() {
                @Override
                public void run() {
                    Glide.with(cardView.getContext())
                            .load(imagefromResponse)
                            .error(mDefaultCardImage)
                            .into(cardView.getMainImageView());
                }
            };
        }
    });


}

okhttp3 使用 glide 异步加载图片时抛出 NetworkOnMainThreadException

okhttp3 throws NetworkOnMainThreadException when loading images asynchronously with glide

android

asynchronous

leanback

android-glide

okhttp3