Android的AsyncTask布爾在加載新頁面後更改爲假

Question

我不完全確定如何解釋這個，但即時通訊新的AsyncTask和im試圖做的是發送UDP數據包到我的服務器，如果我得到一個答覆它設置它如果不是它的離線，則在線。現在，它在第一次打開應用程序時正常工作，但是一旦加載了新頁面，它表示服務器即使在線時仍處於脫機狀態。我不知道它有什麼問題。我是否正確執行AsyncTask或某種程度？這是我能想到的唯一的事情。

CheckStatus.java

import java.io.IOException; 
import java.net.*; 

public class CheckStatus { 
//Check if the server is online 

    public static boolean check() { 

     try { 
      byte[] receiveData = new byte[1024]; 
      InetAddress address = InetAddress.getByName("11.11.11.11"); 
      //create socket 
      DatagramSocket clientSocket = new DatagramSocket(); 
      //set timeout 
      clientSocket.setSoTimeout(1000); 
      //send packet 
      DatagramPacket p = new DatagramPacket(Integer.toBinaryString(0x0006000000).getBytes(), 5, address, 44462); 
       .send(p); 
      //try to receive packet from server 
      DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length); 
      clientSocket.receive(receivePacket); 
      clientSocket.close(); 
      return true; 
     } catch (Exception e) { 
      //if nothing is received set the the server status offline 
      return false; 
     } 
    } 
} 

CheckStatusTask.java

import android.os.AsyncTask; 

class CheckStatusTask extends AsyncTask<Object, Object, Boolean> { 

    private static boolean online; 

    protected Boolean doInBackground(Object... arg0) { 
     boolean flag = CheckStatus.check(); 
     return flag; 
    } 

    protected void onPostExecute(Boolean flag) { 
     online = flag; 
    } 

    public static boolean getOnline(){ 
     return online; 
    } 
} 

main.java

import android.os.Bundle; 
import android.view.View; 

import com.swgproject.projectswg.ActionBar; 

public class Main extends ActionBar { 

//Include res/layout/main.xml 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
    View background = findViewById(R.id.status); 
    View status = findViewById(R.id.image); 
    new CheckStatusTask().execute(); 
    if(CheckStatusTask.getOnline()){ 
     background.setBackgroundResource(R.layout.offline); 
     status.setBackgroundResource(R.drawable.offline); 
    } 
} 


} 

任何幫助是非常讚賞的感謝

Answer 1

現在你的問題是THA你沒有正確地訪問結果。你要求任務執行，然後立即訪問結果而不知道任務是否完成。我建議讓你的異步任務的內部類這樣的，所以它可以訪問的Main變量：

Main.java

public class Main extends ActionBar { 
    private View background; 
    private View status; 

     @Override 
     protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.main); 
      background = findViewById(R.id.status); 
      status = findViewById(R.id.image); 
      new CheckStatusTask().execute(); 
     } 

     class CheckStatusTask extends AsyncTask<Object, Object, Boolean> { 

      protected Boolean doInBackground(Object... arg0) { 
       return CheckStatus.check(); 
      } 

      protected void onPostExecute(Boolean flag) { 
       if(flag){ 
         background.setBackgroundResource(R.layout.offline); 
         status.setBackgroundResource(R.drawable.offline); 
       } 
      } 

     } 

}