我怎么知道后台線程何時完成了 AsyncTask？

Question

我使用帶有背景線程的字符串獲取人員的姓名和電話號碼，並在某處使用它們。 一切正常，但我想做點什么。 當這個線程用完時，我想向用戶展示一些東西。 但我不知道如何檢查這個線程的條件。 如果你幫忙，我將不勝感激。 提前致謝。

cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,
                ContactsContract.Contacts.DISPLAY_NAME + " ASC");

        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {

                while (cursor.moveToNext()){

                    String contactName = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                    String phoneNumber = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)).trim();

                }
                cursor.close();
            }
        });
    }

Answer 1

我想這就是你的意思

    final TextView textView1 = findViewById(R.id.sample_text);
    final Handler uiHandler = new Handler(Looper.getMainLooper());
    AsyncTask.execute(new Runnable() {
        @Override
        public void run() {
            //... your work
            uiHandler.post(new Runnable() {
                @Override
                public void run() {
                    textView1.setText("finish");
                }
            });
        }
    });

Answer 2

你可以這樣做：

public class Processing extends AsyncTask<Void, Void, Void>

  ProgressDialog mProgress;
  @Override
        protected void onPreExecute() {
        super.onPreExecute();
        mProgress = new ProgressDialog(YOUR_ACTIVITIY.this);
        mProgress.setTitle("Processing");
        mProgress.setMessage("Please wait ...");
        mProgress.show();

        @Override
        protected Void doInBackground(Void... voids) {
        cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,
                ContactsContract.Contacts.DISPLAY_NAME + " ASC");

        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {

                while (cursor.moveToNext()){

                    String contactName = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                    String phoneNumber = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)).trim();

                }
                cursor.close();
            }
        });
    }
}
 @Override
    protected void onPostExecute(Void v) {
        super.onPostExecute(v);
        mProgress.dismiss();
   }
}