android异步任务正确使用ui线程

Question

下面是我准备好的代码，它监听位置更新，一旦位置位于指定区域内，它将连接到服务器并开始发送其位置和时间戳，直到它退出该区域。

有人告诉我，不同的方法可能会给 ui 线程带来压力，并且我需要让网络连接在后台或单独的线程上运行，以防止应用程序变慢。

我在 android 文档中阅读了有关 Async Task 的内容。

这是我的问题：

1. 我想我需要在应用程序确定它位于指定区域（矩形）内以及它尝试连接并发送到服务器之后的部分放入一个单独的线程？< /p>

2. 我该怎么做？

   public class GpsActivity 扩展 Activity {
   
   私人位置经理 lm；
   私有LocationListener位置监听器；
   公共静态 TelephonyManager tm；
   公共静态 TextView 电视；
   公共静态 Socket ；
   公共静态 PrintWriter 输出；
   
   
   /**
    * 首次创建活动时调用。
    */
   @覆盖
   公共无效onCreate（捆绑保存实例状态）{
   super.onCreate(savedInstanceState);
   /**
    * 检索引用以提供对设备上电话服务信息的访问     
    */
   tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE); 
   setContentView(R.layout.main);
   /**
   * 检索引用以提供对系统定位服务的访问    
   */              
   lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);    
   
   
    /**
     * 显式选择提供商，创建一组条件并让 android 选择可用的最佳提供商
     */
   
     标准条件 = new Criteria();
     criteria.setAccuracy(Criteria.ACCURACY_FINE);
     criteria.setAltitudeRequired(false);
     criteria.setBearingRequired(false);
     criteria.setCostAllowed(true);
     criteria.setPowerRequirement(Criteria.POWER_LOW);
     字符串提供者 = lm.getBestProvider(criteria, true);
     /**
      * 该方法有四个参数：
      提供商：您注册的提供商的名称
      minTime：通知的最小时间间隔，以毫秒为单位。
      minDistance：通知的最小距离间隔，以米为单位。
      侦听器：每次位置更新都会调用其 onLocationChanged() 方法的对象。
      */
      locationListener = new MyLocationListener();
      lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
   
      电视 = (TextView) findViewById(R.id.textView1);
      tv.setText("我目前没有位置数据。");
   
      }
   
       /**
        * 将Android客户端连接到给定的服务器
        * 
        * @参数名称
        * 远程服务器的名称
        * @参数端口
        * 连接到远程服务器的端口号。
        * @抛出IOException
        * @抛出UnknownHostException
        */
       公共静态无效连接（字符串名称，int端口）
       抛出 UnknownHostException、IOException
   {
   
   s = new Socket(名称,端口);
   out = new PrintWriter(s.getOutputStream(), true);
   }
   
   /**
    * 向服务器发送字符串消息。
    * 
    * @参数消息
    * 要发送的消息。
    * @抛出IOException
    */
    public static void send(String msg) 抛出 IOException
    {
    if (!s.isClosed() && msg != null)
    {
       输出.println(消息);
       if (msg.contains("CMD_QUIT"))
       {
           关闭();
           s.close();
           Log.i("服务器连接", "客户端已断开连接。");
       }
   }
   }
   
    //用于当位置发生变化时接收来自LocationManager的通知
   
   私有类 MyLocationListener 实现 LocationListener{
   
   @覆盖
   公共无效onLocationChanged（位置loc）{
       String txt = "纬度:" + loc.getLatitude() + "/n经度:" + loc.getLongitude();
       Log.i("地理位置", "我当前位置是：\n " + txt);
       tv.setText("我当前位置是：\n" + txt);
       最终字符串 msg = loc.getLongitude() + "\n" + loc.getLatitude() + "\n"
          + loc.getTime();
   
   
       //判断位置是否在指定区域（矩形）内
       双 lat0 = 14.618572；
       双长0 = 120.993816；
       双 lat1 = 14.619652；
       双长1 = 120.992770；
       双 lat2 = 14.620285；
       双长2 = 120.993451；
       双 lat3 = 14.619242；
       双长3 = 120.994497；
       double rel1 = (loc.getLongitude()- long0)*(lat1 - lat0)- ((loc.getLatitude()-lat0)*(long1-long0));
       double rel2 = (loc.getLongitude()- long1)*(lat2 - lat1)- ((loc.getLatitude()-lat1)*(long2-long1));
       double rel3 = (loc.getLongitude()- long2)*(lat3 - lat2)- ((loc.getLatitude()-lat2)*(long3-long2));
       double rel4 = (loc.getLongitude()- long3)*(lat0 - lat3)- ((loc.getLatitude()-lat3)*(long0-long3));
   
       // 如果是，它将连接到服务器并发送位置和时间戳
   
   
       if (rel1 >= 0 && rel2 >= 0 && rel3 >= 0 && rel4 >= 0 )
       {
   
           尝试
           {
           连接（“IP地址”，27960）；
           发送（“CMD_HELLO”）；
           发送（消息）；
           tv.setText("位置在路网内...正在向服务器发送坐标");
           发送（“CMD_QUIT”）；
           } catch (UnknownHostException e)
           {
               // TODO 自动生成的 catch 块
               e.printStackTrace();
           } catch (IOException e)
           {
               // TODO 自动生成的 catch 块
               e.printStackTrace();
           }
           }
   
   
       别的
       {
           tv.setText("当前位置在路网之外");
   
       }
       }
   
   
   
   
   
   @覆盖
   公共无效onProviderDisabled（字符串提供者）{
       // TODO 自动生成的方法存根
   
   }
   
   @覆盖
   公共无效onProviderEnabled（字符串提供者）{
       // TODO 自动生成的方法存根
   
   }
   
   @覆盖
   公共无效onStatusChanged（字符串提供者，int状态，捆绑额外）{
       // TODO 自动生成的方法存根
   
   }
   
           }
           }
   

Answer 1

仅供参考，您可以使用 runnOnUIThread(Runnable R) 来更改文本。

无论如何，使用 AsyncTask 更好，因为连接时不会冻结 UI。

Answer 2

能够做到这一点，并且按照教程操作即可。

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
 /**
  * retrieve a reference to provide access to information about the telephony services on the device     
  */
    tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE); 
    setContentView(R.layout.main);
 /**
  * retrieve a reference to provide access to the system location services    
  */              
lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);    


/**
explicitly select the GPS provider, create a set of Criteria and let android choose 
the best provider available
 */

Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
String provider = lm.getBestProvider(criteria, true);
/**
 * This method takes in four parameters:
provider: The name of the provider with which you register
minTime: The minimum time interval for notifications, in milliseconds.
minDistance: The minimum distance interval for notifications, in meters.
listener: An object whose onLocationChanged() method will be called for each location update.
 */
locationListener = new MyLocationListener();
lm.requestLocationUpdates(provider, 1000, 1, locationListener);

tv = (TextView) findViewById(R.id.textView1);
tv.setText("I currently have no Location Data.");

}

/**
 * Connects the Android Client to a given server
 * 
 * @param name
 *            The name of the remote server
 * @param port
 *            Port number to connect to at the remote server.
 * @throws IOException
 * @throws UnknownHostException
 */
 public static void connect(String name, int port)
        throws UnknownHostException, IOException
{

    s = new Socket(name, port);
    out = new PrintWriter(s.getOutputStream(), true);
}

/**
 * Sends a string message to the server.
 * 
 * @param msg
 *            The message to be sent.
 * @throws IOException
 */
 public static void send(String outmsg) throws IOException
{
    if (!s.isClosed() && outmsg != null)
    {
        out.println(outmsg);
        out.close();
        s.close();
        }}



  //Used for receiving notifications from the LocationManager when the location has changed

private class MyLocationListener implements LocationListener{


    @Override
    public void onLocationChanged(Location loc) {
        String txt = "Latitude:" + loc.getLatitude() + "/nLongitude:" + loc.getLongitude();
        Log.i("GeoLocation", "My current location is:\n " + txt);
        tv.setText("My current location is:\n" + txt);
        String msg=loc.getLongitude() + "\n" + loc.getLatitude() + "\n"
        + loc.getTime();
        tv1 = (TextView) findViewById(R.id.textView2);
        tv2 = (TextView) findViewById(R.id.textView3);  
        //determines if the location is within a designated area (rectangle)
        double lat0 = 14.609794;
        double long0 = 120.986018;
        double lat1 = 14.608966;
        double long1 = 120.986037;
        double lat2 = 14.609031;
        double long2 = 120.984991;
        double lat3 = 14.609877;
        double long3 = 120.985069;
        double rel1 = (loc.getLongitude()- long0)*(lat1 - lat0)- ((loc.getLatitude()-lat0)*(long1-long0));
        double rel2 = (loc.getLongitude()- long1)*(lat2 - lat1)- ((loc.getLatitude()-lat1)*(long2-long1));
        double rel3 = (loc.getLongitude()- long2)*(lat3 - lat2)- ((loc.getLatitude()-lat2)*(long3-long2));
        double rel4 = (loc.getLongitude()- long3)*(lat0 - lat3)- ((loc.getLatitude()-lat3)*(long0-long3));

        // if yes, it will connect to server and send the location and timestamp

       if (rel1 >= 0 && rel2 >= 0 && rel3 >= 0 && rel4 >= 0 )
        {
           tv1.setText("Location is inside the road network...");
           **new connectSend().execute(msg);**  
           }


        else
        {
            tv1.setText("Current location is outside the road network");

        }
        }

    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub

    }

    **public class connectSend extends AsyncTask<String, String, String>{

        @Override
        protected String doInBackground(String... msg) {
            // TODO Auto-generated method stub
            String result;

            try
            {
            connect("ip address", port);

            send(msg[0]);

            result = "SUCCESSFUL coordinates sent to server";

            } catch (UnknownHostException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
                result = "NOT SUCCESSFUL ";
            } catch (IOException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
                result = "NOT SUCCESSFUL ";
            }
            return result;}

        @Override
        protected void onPostExecute(String result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            tv2.setText("result");

            }**


}


    }

}