我对java和Android开发都很陌生，我正在设计一个Android客户端来向服务器发送消息，并从服务器接收消息。它只执行一些功能，首先它将查询服务器的初始状态，然后它将使用该状态更新按钮，并使用充电符号来说明充电器是否正在充电。我已经完成了所有的通信代码，线程似乎发送和接收消息，但线程外的变量没有更新，如果我关闭服务器连接，客户端将保持连接打开，好像服务器还在那里。有人可以给我一些建议，解决我的问题吗？
package charger.app;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.Toast;
public class ChargeTabActivity extends Activity {
String serverIp = "192.168.6.120"; //server Ip address
private static String preqon = "control:Charger:1\r\n"; //sets connection to turn charger on
private static String preqoff = "control:Charger:0\r\n"; //Turn charger off
public boolean connected = false; //connection
//set up buttons
private ImageButton chargeOnOff;
private ImageButton connectButton;
//Set it so that Client Functions can be accessed from main program
ClientFunctions functions = new ClientFunctions();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//initialize UI
setContentView(R.layout.main);
//declare buttons for listeners, and display changes
connectButton = (ImageButton)findViewById(R.id.connectButton);
connectButton.setOnClickListener(connectButtonListener);
chargeOnOff = (ImageButton)findViewById(R.id.chargeOnOff);
chargeOnOff.setOnClickListener(chargeOnOffListener);
Button chargeStatus = (Button)findViewById(R.id.chargeStatus);
////set up strict mode off/////
StrictMode.ThreadPolicy policy = new StrictMode.
ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
/*Listens to see if the connect button is pressed, if it is connected it will
* display connected, else it will try and connect*/
private OnClickListener connectButtonListener = new OnClickListener()
{
public void onClick(View v)
{
if (connected)
{
toast("I am connected");
}
else
{
toast("I am not connected");
}
}
};
/*Listens to see if the Charge on Off Button is pressed, if it is charging it will
* send a request to charge, else it will send a request to stop the charge*/
private OnClickListener chargeOnOffListener = new OnClickListener()
{
public void onClick(View v)
{
//ask server
try {
functions.updateStatus(); //updates the charger status
} catch (IOException e) {
Log.e("Client","Trouble querying",e);
e.printStackTrace();
}
//send message to turn server on or off
if (functions.chargeStatNumber != 0)
{
try {
functions.sendMessage(preqoff);
chargeOnOff.setImageResource(R.drawable.charge_on);
toast("Turning Charger off");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}//end if
else
{
try {
functions.sendMessage(preqon);
chargeOnOff.setImageResource(R.drawable.charge_off);
toast("Turning Charger on");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} //end else
Log.d("ClientActivity", "Charge Button hit" );
//ask server about its status
try {
functions.updateStatus(); //updates the charger status
} catch (IOException e) {
Log.e("Client","Trouble querying",e);
e.printStackTrace();
}
}
};
/////When Application Starts
@Override
public void onStart()
{
super.onStart();
Thread cThread = new Thread(new serverThread()); //Starts the thread that initiates communications
cThread.start();
};
////////On Pause//////This is when a user makes another app, the center point of attention
@Override
public void onPause() {
super.onPause();
functions.closeConnection();
};
//////On Resume/////This is used for when an app exits, and then the user brings it back
@Override
public void onResume() {
super.onResume();
};
//////On Destroy//////////
@Override
public void onDestroy() {
super.onDestroy();
functions.closeConnection();
};
//toast messages
public void toast(String toastMessage)
{
Toast.makeText(DelphiChargeTabActivity.this, toastMessage,
Toast.LENGTH_LONG).show();
};
//Thread to run and receive network connections
public class serverThread implements Runnable
{
public boolean connected = false; //connection
public void run() //runs the thread
{
try
{
functions.connectToServer(serverIp); //connects to server
connected = true;
while (connected)
{
try
{
connectButton.setImageResource(R.drawable.blue_car);
functions.getStreams(); //establish stream connections
functions. updateStatus(); //updates the status of the server
//checkChangeChargeButton(); //sets initial state for charge button
try
{
Thread.sleep(2500);
}
catch ( InterruptedException interruptedException )
{
functions.displayMessage( "\nThread exception" );
} // end catch
}
catch (IOException e)
{
Log.e("Client","Trouble Getting Streams",e);
}
}//end while
}//end try
catch (Exception e)
{
Log.e("Client", "Error Connecting", e);
connected = false;
connectButton.setImageResource(R.drawable.red_car);
}
}; //end run
}; //end serverThread
public void checkChangeChargeButton()
{
if (functions.chargeStatNumber != 0)
{
chargeOnOff.setImageResource(R.drawable.charge_on);
}
else
{
chargeOnOff.setImageResource(R.drawable.charge_off);
}
};
} //This is the Activity close bracket
这是我的函数方法的代码
package charger.app;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.InetAddress;
import java.net.Socket;
import android.util.Log;
public class ClientFunctions
{
private String message;
private String server;
public Socket sock;
private PrintWriter writer;
private DataInputStream inStream;
public Boolean connected;
private String encode = "UTF8";
public byte[] chargerstat;
public int chargeStatNumber; //Used to set the array byte 15 to an int
//inquires server for status of charge
public void updateStatus() throws IOException
{
//Prompt user for server command
System.out.println("Sending request for Charger status data.");
String serverMessage = "meas:Charger?\r\n";
// send the message
sendMessage("meas:Charger?\r\n");
System.out.println();
displayMessage(serverMessage + "sent");
// now receive the message
receiveMessage();
displayMessage("Receive complete");
};
public void connectToServer(String serverIp) throws IOException //Server IP is sent in main app as String "serverIp"
{
//set server IP
//display logcat trying to connect
displayMessage("\nTrying to Connect");
//Start Socket Connection
sock = new Socket( InetAddress.getByName( serverIp ), 18088);
//Display connected
displayMessage( "\nConnected to: " +
sock.getInetAddress().getHostName() );
};
public void getStreams() throws IOException
{
//Set up PrintWriter
writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(sock.getOutputStream())),true);
writer.flush();
//Set Up I
inStream = new DataInputStream(sock.getInputStream());
//display Message Got I/O
displayMessage("\nGot IO Streams");
};
public void sendMessage(final String serverMessage) throws UnsupportedEncodingException
{
//set variable for message
message = serverMessage;
//sends message
writer.printf("%s", message);
writer.flush();
//display message sent
displayMessage("\nsent" /*+ serverMessage*/);
};
public static int getInt(byte[] array, int offset)
{
return
((array[offset+3] & 0xff) << 24) |
((array[offset+2] & 0xff) << 16) |
((array[offset+1] & 0xff) << 8) |
(array[offset] & 0xff);
}
public void receiveMessage() throws IOException
{
{
int c=0;
int i;
int seqcountval;
chargerstat = new byte[96];
i=0;
while(i < 96)
{
try
{
c = inStream.read();
chargerstat[i] = (byte)c;
}
catch ( IOException ioException )
{
ioException.printStackTrace();
} // end catch
// uncomment this to see each byte
//displayMessage(":" + i + " " + chargerstat[i]);
i++;
}
seqcountval = getInt(chargerstat, 76);
displayMessage("SeqCntr = " + seqcountval);
chargeStatNumber = chargerstat[15];
};
};
public void closeConnection()
{
//closes connections
displayMessage("\n\nClosing Connection");
try
{
writer.close();
inStream.close();
sock.close();
}
catch ( IOException ioException )
{
ioException.printStackTrace();
} // end catch
};
public void displayMessage( final String messageToDisplay )
{
new Runnable()
{
public void run() // updates displayArea
{
//change to log.d for android
System.out.println(messageToDisplay);
} // end method run
}; // end anonymous inner class
} // end method displayMessage
};
答案 0 :(得分：1)
为什么不使用AsyncTask而不是Thread，分享信息会更容易，并且似乎适用于你想要做的事情。
使用AsyncTask
AsyncTask允许您对用户执行异步工作 接口。它在工作线程中执行阻塞操作 然后在UI线程上发布结果，无需您 自己处理线程和/或处理程序。
http://developer.android.com/guide/topics/fundamentals/processes-and-threads.html
ChargerActivity中的“connected”变量与ServerThread中的变量不同，因此不会从线程更新ChargerActivity的连接。
答案 1 :(得分：1)
socket函数不能在android 4.0之后的ui线程中使用，比如你的connect funciton和sendMessage
答案 2 :(得分：0)
您无法从其他线程更新UI。您必须在主线程中更新UI。如果您想从不同的线程更新UI，您可以执行类似这样的操作
public void changeButtonImage(){
runOnUiThread(new Runnable(){
@Override
public void run() {
connectButton.setImageResource(R.drawable.blue_car);
}});
}