AsyncTask没有调用onProgressUpdate,onPostExecute

Question

我试图理解AsyncTask在Android上的使用,为此我已经开发了这个简单的代码.

令人惊讶的是,doInbackground被正确调用,我看到了日志,但没有调用其他两个方法.

我错过了什么吗？

谢谢advancde

  public class DownloadFilesTask extends AsyncTask<Void, Void, Void> {

        protected Void doInBackground(Void... params) {
            try {
                Log.i("Thread","1");
                Thread.sleep(1000);
                Log.i("Thread","2");
                Thread.sleep(1000);
                Log.i("Thread","3");
                Thread.sleep(1000);
                Log.i("Thread","4");
                Thread.sleep(1000);
                Log.i("Thread","5");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return null;
        }

        protected void onProgressUpdate(Void... progress) {
            Log.i("Thread","onProgress");
        }

        protected void onPostExecute(Void... result) {
            Log.i("Thread","onPosts");
        }
    }

[编辑]

使用此代码,所有工作正常,除了 onProgressUpdate

public class DownloadFilesTask extends AsyncTask<Void, Integer, String> {

public String doInBackground(Void... params) {
    try {
        int i = 0;
        Log.i("Thread","1");
        Thread.sleep(1000);
        publishProgress(i++);
        Log.i("Thread","2");
        Thread.sleep(1000);
        publishProgress(i++);
        Log.i("Thread","3");
        Thread.sleep(1000);
        Log.i("Thread","4");
        Thread.sleep(1000);
        Log.i("Thread","5");
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    return "done";
}

public void onProgressUpdate(int progress) {
    Log.i("Thread","onProgress " + progress);
}

public void onPostExecute(String result) {
    Log.i("Thread","onPosts " + result);
}

在这里,您可以看到我的LogCat的屏幕截图

Answer 1

方法签名是错误的.它应该看起来像:

protected void onPostExecute(Void result) {
    Log.i("Thread","onPosts");
}

另外,我建议你使用@Override注释.这样,如果您尝试覆盖错误的方法,则会出现编译时错误.

编辑:您发布的onProgressUpdate的签名是错误的.它应该是:

protected void onProgressUpdate(Integer... progress){}