Java 从readLine()方法接收到无限个空值
我制作了一个应用程序,将加速度计坐标发送到我的电脑。android客户端的代码是:Java 从readLine()方法接收到无限个空值,java,android,sockets,tcp,client-server,Java,Android,Sockets,Tcp,Client Server,我制作了一个应用程序,将加速度计坐标发送到我的电脑。android客户端的代码是: public class MainActivity extends Activity implements SensorEventListener{ private SensorManager senSensorManager; private Sensor senAccelerometer; private long lastUpdate = 0; float x ; float y ; float z; Te
public class MainActivity extends Activity implements SensorEventListener{
private SensorManager senSensorManager;
private Sensor senAccelerometer;
private long lastUpdate = 0;
float x ;
float y ;
float z;
TextView xt,yt,zt;
String st="left";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
senSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
senAccelerometer = senSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
senSensorManager.registerListener(this,senAccelerometer,SensorManager.SENSOR_DELAY_NORMAL);
xt= (TextView) findViewById(R.id.xc);
yt= (TextView) findViewById(R.id.yc);
zt= (TextView) findViewById(R.id.zc);
new SendMsg().execute();
}
public void onSensorChanged(SensorEvent sensorEvent) {
Sensor mySensor = sensorEvent.sensor;
if (mySensor.getType() == Sensor.TYPE_ACCELEROMETER) {
x = sensorEvent.values[0];
y = sensorEvent.values[1];
z = sensorEvent.values[2];
long curTime = System.currentTimeMillis();
if ((curTime - lastUpdate) > 100) {
long diffTime = (curTime - lastUpdate);
lastUpdate = curTime;
xt.setText(String.valueOf(x));
yt.setText(String.valueOf(y));
zt.setText(String.valueOf(z));
}
}
}
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
protected void onPause() {
super.onPause();
senSensorManager.unregisterListener( this);
}
protected void onResume() {
super.onResume();
senSensorManager.registerListener( this, senAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
}
private class SendMsg extends AsyncTask<String, Void, String> {
Socket s= null;
OutputStream os;
PrintWriter pw;
@Override
protected String doInBackground(String... params) {
try {
s = new Socket("192.168.0.102",2345);
os=s.getOutputStream();
pw=new PrintWriter(os);
while(true){
pw.println(x+" "+y+" "+z);
}
} catch (IOException e) {
e.printStackTrace();
}
return "executed";
}
protected void onPostExecute(String result) {
}
}
应用程序没有发送加速计坐标,而是发送NULL,并在服务器端打印
尽管我很努力,还是没能找出问题所在。你错了。TCP不能“发送空”。
readline()
方法返回null,*而不是您接收数据
原因很简单,readLine()。这在Javadoc中有明确的说明。当它返回null时,对等方已关闭连接,因此您必须停止读取并通常关闭套接字。通常的书写方式是:
while ((line = br.readLine()) != null)
{
// ...
}
您是否尝试过使用“log.d”语句来查看您得到了什么?放在pw.println语句的旁边。什么?当然,你不会期望谷歌系统呼叫或阅读手册页的海报吧?
while ((line = br.readLine()) != null)
{
// ...
}