Android - 异步任务不将数据传递到私有(private)数组中？

Question

尝试使用 asynctask 进行延迟加载。它的 75% 工作正常；能够在 doInBackground() 中运行方法。但是加载后 UI 不会更新。我意识到内容没有存储在我声明的数组中(如果我没有使用 asynctask)。看到了 onProgressUpdate 和 publishUpdate 但不确定如何使用它们。运行 searchContent() 后，数据将存储在 mStrings[] 和 dStrings[] 中，以便可以将其传递到我的适配器。有帮助吗？

你好类.java

public class HelloClass extends Activity {

ListView list;
LazyAdapter adapter;

ProgressDialog dialog;
private String[] mStrings = {};
private String[] dStrings = {};

 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main); 

    new TheTask().execute();        

    list=(ListView)findViewById(R.id.list);         
    adapter=new LazyAdapter(this, mStrings, dStrings);
    list.setAdapter(adapter);

}

protected class TheTask extends AsyncTask<Void, Void, Void>{

    protected void onPreExecute() {
        dialog = ProgressDialog.show(HelloClass.this, "Retrieving Information", "Please wait for few seconds...", true, false);
    }

    protected Void doInBackground(Void... params) {
        searchContent();
        return null;
    }

    protected void onPostExecute(Void result) {
        dialog.dismiss();
    }
}

public void searchContent()
{
    String imageC = "";
    String textC = "";


    try {

        URL url = new URL(targetURL);

        // Make the connection
        URLConnection conn = url.openConnection();
        BufferedReader reader = new BufferedReader(
         new InputStreamReader(conn.getInputStream()));

        String line = reader.readLine();

        while (line != null) {

            if(line.contains("../../"))
            {

                String xyz = line.substring(0,xyz.indexOf('"'));
                imageC = xyz +";";                  
                mStrings = imageC.split(";");
                line = reader.readLine();
            }

            if(line.contains("../../") == false)
            {
                line = reader.readLine();
            }

            if (line.contains("Nametag"))
            {
                int startIndex = line.indexOf("Gnametag") + 10;
                int endIndex = line.indexOf("<", startIndex + 1);
                String gname = line.substring(startIndex,endIndex);
                textC = textC.replaceAll("</span>", "");
                textC += "Name: "+gname+ "\n";
            }                   

                if (line.contains("Age"))
                {
                    textC += "Age: "+reader.readLine() + "\n" + ";";
                    textC = textC.replaceAll("                  ", "");
                dStrings = textC.split(";");
                }

            if (line.contains("Last Update"))
            {
                reader.close();
            }                               
        }           

        // Close the reader
        reader.close();

    } catch (Exception ex) {
        ex.printStackTrace();           
    }


}

适配器.java

public class LazyAdapter extends BaseAdapter {

private Activity activity;
private String[] data;
private String[] text;
private static LayoutInflater inflater=null;
public ImageLoader imageLoader; 

public LazyAdapter(Activity a, String[] d, String[] t) {
    activity = a;
    data=d;
    text = t;
    inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    imageLoader=new ImageLoader(activity.getApplicationContext());
}

编辑:

protected class TheTask extends AsyncTask<Void, Void, Void>{

    protected void onPreExecute() {
        dialog = ProgressDialog.show(HelloClass.this, "Retrieving Information", "Please wait for few seconds...", true, false);
    }

    protected void doInBackground(String[]... params) {
        searchContent();
        MyResultClass result = new MyResultClass();
        result.mStrings = mStrings;
        result.dStrings = dStrings;
        return result;
    }   
    protected void onPostExecute(String[] result) {
        dialog.dismiss();
    }

}

class MyResultClass
{ 
    public String[] mStrings; 
    public String[] dStrings; 

}

Answer 1

您的适配器在内部保留自己的数据结构。这意味着如果你想改变它的状态，你必须直接在它上面操作。

在您的情况下，您应该在完成工作后在适配器中再次设置 mStrings 和 dStrings。

publishUpdate 和 onProgressUpdate 用于在任务运行时与 UI 交互，例如当您想要显示进度条时。