安卓异步任务

Question

我是否充分利用了我的 AsyncTask？如果错误，有人可以更正我的代码。我只想确保我的 AsyncTask 完全正常工作，这样我以后就不会遇到任何麻烦。我希望在所有类(class)中使用 AsyncTask。这是一个好的做法吗？

    public class SingleMenuItemActivity  extends Activity {

    // XML node keys
static final String KEY_TITLE = "title";
static final String KEY_ARTIST = "artist";  
static final String KEY_THUMB_URL = "thumb_url";
private ProgressDialog pDialog;
String title;
String artist;
String image_url;
ImageView view;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.single_list_item);
        new loadSingleView().execute(); 


        view = (ImageView) findViewById(R.id.single_image);
    }


public class loadSingleView extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(
                    SingleMenuItemActivity.this);
            pDialog.setMessage("Connecting to Server ...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }
        @Override
        protected String doInBackground(String... args) {
            // updating UI from Background Thread


            Intent in = getIntent();

            image_url = in.getStringExtra(KEY_THUMB_URL);
                        title = in.getStringExtra(KEY_TITLE);
            artist = in.getStringExtra(KEY_ARTIST);


            return null;

                    }
        @Override       
        protected void onPostExecute(String args) {
            // dismiss the dialog after getting all products

            ImageLoader imgLoader = new ImageLoader(getApplicationContext());

            imgLoader.DisplayImage(image_url, view);

            TextView lblName = (TextView) findViewById(R.id.name_title);
            TextView lblCost = (TextView) findViewById(R.id.name_artist);

            lblName.setText(title);
            lblCost.setText(artist);
            pDialog.dismiss();
        }
}

Answer 1

您无法从后台线程更新 UI。例如使用doInBackground()从服务器获取数据。所有这些过程将在后台完成。而onPostExecute是在后台进程结束后更新UI

For more info Study here

Example1

Example2

您可以在 Google 中找到更多 :)