okhttp3抛出NetworkOnMainThreadException与滑行异步加载图像
问题描述:
我试图加载图像异步到Leanback中的CardPresenter像这样。okhttp3抛出NetworkOnMainThreadException与滑行异步加载图像
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);
}
不幸的是预期,这并不工作。 只有少数图像正确载入卡演示,但其中大部分都没有了,下面的错误被抛出:
android.os.NetworkOnMainThreadException
android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1303)
这是完全随机的,其工作,哪些没有。
我也尝试在MainActivity.java中设置严格模式。
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
虽然这种解决方案正确加载的所有图像,并且不抛出任何NetworkOnMainThreadException
错误,它带有巨大的性能问题。滚动变得缓慢和laggy,我展示了以下消息:
I/Choreographer: Skipped 182 frames! The application may be doing too much work on its main thread.
有没有什么解决办法,使图像负载异步同时仍保持平稳和良好的性能?
答
我的方法是完全错误的。我认为BaseGlideUrlLoader
在后台线程上运行,但它不。
因此,代码走的是以下几点:
@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());
}
};
}
});
}
我相信此行'client.newCall(请求).execute()身体()的字符串();'是的同步执行。网络请求并导致您的问题。 – peitek
你是对的...我使用这段代码是因为我认为'BaseGlideUrlLoader'运行在后台线程上。 –