android - 从 AsyncTask 单独线程访问 fragment 对象

Question

我正在从一个 fragment 中调用一个 asyncTask 来做一些网络。当它运行时，我需要能够禁用 fragment 中的按钮，直到 AsyncTask 调用 onPostExecute。

我唯一的问题是我无法从 doInBackground 访问这样的按钮:

Button mButtom = mActivity.findViewById(R.id.testButton);

它带来了:

java.lang.RuntimeException: An error occured while executing doInBackground()
     at android.os.AsyncTask$3.done(AsyncTask.java:300)
     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
     at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.IllegalStateException: The current thread must have a looper!

Answer 1

我们有一个名为 runOnUIThread 的函数

@Override protected String doInBackground(String... strings) {
    activity.runOnUiThread(new Runnable() {
      @Override public void run() {
    //do your action
      }
    });
    return "";
  }