android - 一般如何停止 AsyncFacebookRunner 或停止请求？

Question

我有一个 AsyncFacebookRunner 可以将图像上传到 Facebook。我想创建一个取消按钮来停止下载。

如何才能做到这一点？

编辑:

我是这样用的:

byte[] data = null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
data = baos.toByteArray();
Bundle params = new Bundle();
params.putByteArray("picture", data);
AsyncFacebookRunner mAsyncRunner = new AsyncFacebookRunner(facebook);
mAsyncRunner.request("me/photos", params, "POST", 
new PhotoUploadListener(dialog), null);

Answer 1

您始终可以扩展 AsyncFacebookRunner 类并覆盖 request 方法。
像这样:

public class CancelableAsyncFacebookRunner extends AsyncFacebookRunner {
    private Thread requestThread;

    public AsyncFacebookRunner(Facebook fb) {
        super(fb);
    }

    @Override
    public void request(final String graphPath,
            final Bundle parameters,
            final String httpMethod,
            final RequestListener listener,
            final Object state) {

        this.requestThread = new Thread() {
            @Override
            public void run() {
                try {
                    String resp = fb.request(graphPath, parameters, httpMethod);
                    listener.onComplete(resp, state);
                } catch (FileNotFoundException e) {
                    listener.onFileNotFoundException(e, state);
                } catch (MalformedURLException e) {
                    listener.onMalformedURLException(e, state);
                } catch (IOException e) {
                    listener.onIOException(e, state);
                }
            }
        };
    }

    public void cancel() {
        this.requestThread.interrupt();
    }
}

它还没有经过测试，但应该给你大概的想法。

---

编辑

现在我想起来了，这没什么意义，因为您想使用 AsyncFacebookRunner 发出多个请求，而 cancel 只会取消最后一个请求。

我会建议返回线程，然后可以在其他地方中断它，但是你不能像这样更改方法的签名，创建新方法将无法使用其他 AsyncFacebookRunner 类中定义的 request 方法。

相反，您可以执行以下操作:

public class CancelableAsyncFacebookRunner extends AsyncFacebookRunner {
    private Hashtable<String, Thread> requestThreads;

    public AsyncFacebookRunner(Facebook fb) {
        super(fb);
        this.requestThreads = new Hashtable<String, Thread>();
    }

    @Override
    public void request(final String id, 
            final String graphPath,
            final Bundle parameters,
            final String httpMethod,
            final RequestListener listener,
            final Object state) {
        Thread thread = new Thread() {
            @Override
            public void run() {
                try {
                    String resp = fb.request(graphPath, parameters, httpMethod);
                    requestThreads.remove(id);
                    listener.onComplete(resp, state);
                } catch (FileNotFoundException e) {
                    requestThreads.remove(id);
                    listener.onFileNotFoundException(e, state);
                } catch (MalformedURLException e) {
                    requestThreads.remove(id);
                    listener.onMalformedURLException(e, state);
                } catch (IOException e) {
                    requestThreads.remove(id);
                    listener.onIOException(e, state);
                }
            }
        });

        this.requestThreads.put(id, thread);
        thread.start();
    }

    public void cancel(String id) {
        if (this.requestThreads.containsKey(id) {
            this.requestThreads.get(id).interrupt();
        }
    }
}

您需要以某种方式为请求生成一个 id，可以是一些简单的东西，例如:

String.valueOf(System.currentTimeMillis());