android - 在android中，如果我在线程中运行网络请求但不想在响应返回之前刷新UI怎么办？

Question

就像我需要检查用户名是否已经存在于数据库中，并且在响应到达之前程序不会继续。

Answer 1

看来您需要 asynctask，这是一个如何使用它的示例..

    public class YourFragment extends Fragment implements YourAsyncTask.YourInterface {


    public YourFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view =  inflater.inflate(R.layout.fragment_your, container, false);



        //do your initial things
        .
        .
        .

        YourAsyncTask yourAsyncTask = new YourAsyncTask(this);
        yourAsyncTask.execute();

        return view;
    }

    @Override
    public void onJobFinishListener(YourDataType yourData) {
        //when this method is trigered by your asynctask 
        //it means that you are in ui thread and update your ui component

        //TODO: update ui component with your data
    }
}

这是异步任务；

public class YourAsyncTask extends AsyncTask {

    private YourInterface yourInterfaceListener;

    private YourDataType yourData; //this data should be calculated in doInBackground method and send via interface

    public YourAsyncTask(YourInterface yourInterfaceListener) {
        this.yourInterfaceListener = yourInterfaceListener;
    }

    @Override
    protected Object doInBackground(Object[] objects) {
        //do your all background tasks here
        .
        .
        .
        yourData = do something here to fill your data..

        return null;
    }

    @Override
    protected void onPostExecute(Object o) {
        super.onPostExecute(o);
        yourInterfaceListener.onJobFinishListener(yourData);
    }

    public interface YourInterface{
        void onJobFinishListener(YourDataType yourData);
    }
}