Question

我想解雇我在postexecute中的构造函数中启动的progressdialog.But postexecute无法执行。我试图在doInBackground（）方法中打印一条消息，但即使那样也没有打印。但是当我不这样做时它工作正常没有显示对话框。请帮助，谢谢。

public class MyJsonParser extends AsyncTask<Void, Integer, List<Category>>
{

    private static final String categoriesUrl = "some_url1";
    private static final String postsUrl = "some_url2";
    private List<Category> categories = new ArrayList<Category>();
    private Context context;
    private ProgressDialog pDialog;
    private Activity activity;

    public MyJsonParser(Context context)
    {
        this.context = context;
        this.activity = (Activity) context;
        pDialog = ProgressDialog.show(context, "Loading", "Please wait...");

    }

    @Override
    protected List<Category> doInBackground(Void... params)
    {

        HttpClient client = new DefaultHttpClient();
        HttpGet get1 = new HttpGet(categoriesUrl);
        HttpResponse response1;

        try
        {
                        System.out.println("doInBackground");
            response1 = client.execute(get1);
            StatusLine statusLine = response1.getStatusLine();
            if (statusLine.getStatusCode() == 200)
            {
                try
                {
                    HttpEntity entity = response1.getEntity();
                    InputStream content = entity.getContent();
                    Reader reader = new InputStreamReader(content);
                    Gson gson = new Gson();
                    JsonParser parser = new JsonParser();
                    JsonObject jsObject = parser.parse(reader)
                            .getAsJsonObject();
                    JsonElement jsElement = jsObject.get("categories");
                    Type type = new TypeToken<List<Category>>()              {}.getType();
                    categories = gson.fromJson(jsElement, type);
                    content.close();
                } catch (JsonIOException ex)
                {
                    System.out.println("JsonIOException");
                } catch (JsonParseException ex)
                {
                    System.out.println("JsonIOException");
                }
            }

        } catch (ClientProtocolException e)
        {

            e.printStackTrace();
        } catch (IOException e)
        {

            e.printStackTrace();
        }


        for(int i=0;i<categories.size();i++)
        {
            List<Post> posts = new ArrayList<Post>();
            HttpGet get2 = new HttpGet(postsUrl+categories.get(i).getId());
            HttpResponse response2; 
          try
          {

             response2 = client.execute(get2);
             StatusLine statusLine = response2.getStatusLine();
             if (statusLine.getStatusCode() == 200)
            {
                try
                {
                    HttpEntity entity = response2.getEntity();
                    InputStream content = entity.getContent();
                    Reader reader = new InputStreamReader(content);
                    Gson gson = new Gson();
                    JsonParser parser = new JsonParser();
                    JsonObject jsObject = parser.parse(reader)
                            .getAsJsonObject();
                    JsonElement jsElement = jsObject.get("posts");
                    Type type = new TypeToken<List<Post>>(){}.getType();
                    posts = gson.fromJson(jsElement, type);
                    content.close();

                } catch (JsonIOException ex)
                {
                    System.out.println("JsonIOException");
                } catch (JsonParseException ex)
                {
                    System.out.println("JsonIOException");
                } 
             }

            } catch (ClientProtocolException e)
            {

                e.printStackTrace();
            } catch (IOException e)
            {
                e.printStackTrace();
            }

              categories.get(i).setPosts(posts); 
              //publishProgress((int)progressbar.getMax()/i);
            } 

        return categories;
    }

    @Override
    protected void onPreExecute()
    {

        System.out.println("onPreExecuteeeeeeeeeeeeeeeeeeeeeeeeeeeeeee");
        //activity.findViewById(R.id.progressBar1);
        //activity.setProgress(0);
        //pDialog.setMessage("Plz wait");
        // pDialog.show();
         super.onPreExecute();
    }



    @Override
    protected void onPostExecute(List<Category> result)
    {

    Intent intent = new Intent(context, BaseContent.class);
    intent.putExtra("categories", (ArrayList<Category>) result);
    context.startActivity(intent);
    pDialog.dismiss();
        activity.finish();
        super.onPostExecute(result);
    }

}

Answer 1

如何在onPreExecute（）而不是构造函数中显示进度对话框，onPreExecute（）在UI线程中运行。

@Override
protected void onPreExecute()
{    
    System.out.println("onPreExecuteeeeeeeeeeeeeeeeeeeeeeeeeeeeeee");
    pDialog = ProgressDialog.show(activity, "Loading", "Please wait...");
    super.onPreExecute();
}

progressDialog旋转时，AsyncTask不起作用

1 个答案: