Question

我想在此代码中添加一个进度对话框，因此当我单击按钮加载此活动时，它不会挂起或在几秒钟内显示黑屏。它也必须在异步任务中吗？我愿意尝试使用Async任务，只是尝试了几次而且我没有让它工作

package net.thinkbin;

import java.util.ArrayList;
import java.util.HashMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class entertainment extends ListActivity {

private static final String TITLE = "Title";
private static final String AUTHOR = "Author";
private static final String VIEWS = "Views";
private static final String RATES = "Rates";
private static final String CONTENT = "Content";

JSONArray ideas = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub


    super.onCreate(savedInstanceState);
    setContentView(R.layout.listplaceholder3);


    Button view = (Button) findViewById(R.id.button1);
    view.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            startActivity(new Intent("net.thinkbin.TUTORIAL1"));
            overridePendingTransition(0, 0);
            finish();
        }
    });

    Button share = (Button) findViewById(R.id.button2);
    share.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            startActivity(new Intent("net.thinkbin.SHARE"));
            overridePendingTransition(0, 0);
            finish();
        }
    });

    Button menu = (Button) findViewById(R.id.buttonhome);
    menu.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            startActivity(new Intent("net.thinkbin.MENU"));
            overridePendingTransition(0, 0);
            finish();
        }

    });

    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String,   String>>();


    JSONObject json =     JSONfunctions.getJSONfromURL("http://www.thinkbin.net/include/api/index.php?cat=Entertainment&type=Views&i=10");

    try{

            ideas = json.getJSONArray("Ideas");

            // looping through All Contacts
        for(int i = 0; i < ideas.length(); i++){
            JSONObject c = ideas.getJSONObject(i);

            // Storing each json item in variable
            String title = c.getString(TITLE);
            String author = c.getString(AUTHOR);
            String views = c.getString(VIEWS);
            String rates = c.getString(RATES);
            String content = c.getString(CONTENT);

            // creating new HashMap
            HashMap<String, String> map = new HashMap<String, String>();

            // adding each child node to HashMap key => value
            map.put(TITLE, "Title: " + title);
            map.put(AUTHOR, "Author: " + author);
            map.put(VIEWS, "Views: " + views);
            map.put(RATES, "Rates: " + rates);
            map.put(CONTENT, content);

            // adding HashList to ArrayList
            mylist.add(map);


        }   


    }catch(JSONException e)        {
         Log.e("log_tag", "Error parsing data "+e.toString());
    }

    ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.main2, 
                    new String[] { TITLE, AUTHOR, VIEWS, RATES, CONTENT }, 
                    new int[] { R.id.item_title, R.id.item_subtitle, R.id.item3, R.id.item4, R.id.item5 });

    setListAdapter(adapter);

 // selecting single ListView item
    ListView lv = getListView();

    // Launching new screen on Selecting Single ListItem
    lv.setOnItemClickListener(new OnItemClickListener() {

        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // getting values from selected ListItem
            String Title2 = ((TextView) view.findViewById(R.id.item_title)).getText().toString();
            String Author2 = ((TextView) view.findViewById(R.id.item_subtitle)).getText().toString();
            String Content2 = ((TextView) view.findViewById(R.id.item5)).getText().toString();

            Intent in = new Intent(getApplicationContext(), idea.class);
            overridePendingTransition(0, 0);
            in.putExtra(TITLE, Title2);
            in.putExtra(AUTHOR, Author2);
            in.putExtra(CONTENT, Content2);


            startActivity(in);


        }
    });

}                       
}

Answer 1

您不必AsyncTask就可以Activity implements Runnable Thread.start(this)，然后从onClick致电void run() {...}，将您的代码放入您的Activity Thread.start()。然后在runOnUiThread(new Runnable() { public void run() { dismissDialog(YOUR_DLG)) }之前显示对话框，并在任务结束时终止对话框。但是请注意，在杀死你时你必须做{{1}}，因为只能从UI线程控制UI。

AsyncTask虽然更好。

Answer 2

我使用以下代码显示ProgressDialog，

progDailog = ProgressDialog.show(loginAct,"Process ", "please wait....",true,true);  
new Thread ( new Runnable() 
{      
      public void run()      
      {       
             // your code goes here      
      } 
}).start();   

Handler progressHandler = new Handler()   
{       
       public void handleMessage(Message msg1)       
       {           
             progDailog.dismiss();          
       }  
}

Answer 3

您问题的最佳解决方案是使用异步任务。因为Async任务有很少的方法，如

onPreExecute() - 在这里初始化你的任务。
doInBackground() - 在这里，您可以获得网络点击。即从服务器获取数据。
onPostExecute() - 在这里处理从服务器收到的响应以及与UI相关的任务。

除此之外，它还有一个方法

onProgressUpdate() - 可用于发布已完成任务的进度。

这是显示有关如何使用AsyncTask的示例的Link。

如何将ProgressDialog添加到此代码中

3 个答案: