我已经尝试了几个小时来获取我的应用程序(在Android 7.1.2上运行)连接到家庭局域网中桌面PC上的服务器插槽。
public class MainActivity extends AppCompatActivity {
static final String SERVER_IP = "192.168.XXX.XXX"; // X's are replaced by actual IP
static final int PORT = 30000;
Socket clientSocket;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Button btReceive = (Button) findViewById(R.id.btReceive);
final TextView txtReceivedText = (TextView) findViewById(R.id.txtReceivedText);
final TextView txtStatus = (TextView) findViewById(R.id.txtStatus);
btReceive.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v) {
txtStatus.setText("Received button pressed.");
try {
Socket s = new Socket(SERVER_IP, PORT);
BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
final String st = input.readLine();
txtReceivedText.setText(st);
s.close();
} catch (IOException e) {
e.printStackTrace();
}
});
}
}
执行后,我在Android工作室的控制台上获得输出:
...
Waiting for process to come online
Connected to process 16980 on device samsung-gt_i9515-a72266ed
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
W/art: Before Android 4.1, method int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.jonas.network_connector, PID: 16980
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1303)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:333)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:196)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:356)
at java.net.Socket.connect(Socket.java:605)
at java.net.Socket.connect(Socket.java:554)
at java.net.Socket.<init>(Socket.java:431)
at java.net.Socket.<init>(Socket.java:210)
at com.example.jonas.network_connector.MainActivity$2.onClick(MainActivity.java:88)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22433)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6186)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:889)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:779)
I/Process: Sending signal. PID: 16980 SIG: 9
Application terminated.
由于我不熟悉套接字编程(以及android),我不知道如何继续查找错误。
我的清单有权限行:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
答案 0 :(得分:2)
android.os.NetworkOnMainThreadException
此异常告诉您正在尝试在主线程中调用remote。尝试使用AsyncTask进行调用,问题不应再次出现。 Android操作系统阻止在主线程中执行长时间运行的操作,因为它可以锁定UI。
答案 1 :(得分:2)
您需要在工作线程上进行网络工作。
btReceive.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v) {
txtStatus.setText("Received button pressed.");
new Thread(new Runnable() {
@Override
public void run() {
try {
Socket s = new Socket(SERVER_IP, PORT);
BufferedReader input = new BufferedReader(new InputStreamReader(s.getInputStream()));
final String st = input.readLine();
txtReceivedText.post(new Runnable(){
@Override
public void run() {
txtReceivedText.setText(st);
}
});
s.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}).start();
});
答案 2 :(得分:1)
android.os.NetworkOnMainThreadException
这意味着您的应用程序尝试在其主线程上执行网络操作。在AsyncTask中运行您的代码。
示例:
class TCPTask extends AsyncTask<Void, Void, Void>{
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... params) {
return null;
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
}
}
执行异步任务:
在oncreate()方法中添加此代码
new TCPTask().execute();