一、概述

LocalSocket可以在Android上实现跨进程的通信；区分服务端和客户端，服务端需要监听客户端发送过来的消息。

二、服务端实现

xml文件

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical">

android:id="@+id/tvMsg"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:minHeight="300dp"

android:text="收到消息"

android:textColor="#000000" />

android:background="#888888"

android:id="@+id/tvToSend"

android:layout_width="match_parent"

android:layout_height="50dp"

android:gravity="center"

android:text="去发送信息"

android:textColor="#000000" />

java代码

public class LocalSocketServerActivity extends Activity {

private TextView tvMsg;

private LocalServerSocket mServerSocket = null;

private LocalSocket mSocket = null;

private InputStream mInputStream = null;

private static final String SOCKET_NAME = "demos.android.stormdzh.com.androiddemos.localsocket";

private static final String TAG = LocalSocketServerActivity.class.getSimpleName();

private final Handler mHandler = new Handler() {

public void handleMessage(android.os.Message msg) {

String dispMesg = (String) msg.obj;

tvMsg.setText(dispMesg);

}

};

@Override

protected void onCreate(@Nullable Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_local_socket_server);

tvMsg = findViewById(R.id.tvMsg);

createServerSocket();// 创建LocalServerSocket

//必须要在子线程里接收消息

new Thread(new Runnable() {

@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)

@Override

public void run() {

acceptMsg();

}

}).start();

findViewById(R.id.tvToSend).setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

startActivity(new Intent(LocalSocketServerActivity.this,LocalSocketClientActivity.class));

}

});

}

@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)

private void acceptMsg() {

try {

mSocket = mServerSocket.accept();//accept是个阻塞方法，这就是必须要在子线程接收消息的原因。

} catch (IOException e1) {

e1.printStackTrace();

}

while (true) {

try {

byte[] buffer = new byte[1024];

mInputStream = mSocket.getInputStream();

int count = mInputStream.read(buffer);

String key = new String(Arrays.copyOfRange(buffer, 0, count));

Log.d(TAG, "ServerActivity mSocketOutStream==" + key);

if ("stop".equals(key)) {

closeSocketResource();

break;

}

Message msg = mHandler.obtainMessage();

msg.obj = key;

msg.sendToTarget();

} catch (IOException e) {

Log.d(TAG, "exception==" + e.fillInStackTrace().getMessage());

e.printStackTrace();

}

}

}

@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)

private void closeSocketResource() {

closeSlient(mInputStream);

closeSlient(mSocket);

try {

if (mServerSocket != null) {

mServerSocket.close();

mServerSocket = null;

}

} catch (IOException ex) {

Log.e(TAG, "Failed closing ServerSocket" + ex.fillInStackTrace());

}

}

private void closeSlient(Closeable closeable) {

try {

if (closeable != null) {

closeable.close();

closeable = null;

}

} catch (IOException ex) {

Log.e(TAG, "Failed closing : " + closeable);

}

}

private void createServerSocket() {

if (mServerSocket == null) {

try {

/**注意这里new出LocalServerSocket的同时，系统层已经同步做了bind和listen。

* 我们看看new的过程：

* public LocalServerSocket(String name) throws IOException {

* impl = new LocalSocketImpl();

* impl.create(LocalSocket.SOCKET_STREAM);

* localAddress = new LocalSocketAddress(name);

* impl.bind(localAddress);

* impl.listen(LISTEN_BACKLOG);

* }

*/

mServerSocket = new LocalServerSocket(SOCKET_NAME);

} catch (IOException ex) {

}

}

}

}

三、客户端实现

xml文件

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical">

android:id="@+id/input_msg"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="10dp" />

android:id="@+id/replay_btn"

android:layout_width="match_parent"

android:layout_height="50dp"

android:layout_marginTop="10dp"

android:background="#765432"

android:gravity="center"

android:text="回复"

android:textColor="#000000" />

android:id="@+id/stop_btn"

android:layout_width="match_parent"

android:layout_height="50dp"

android:layout_marginTop="10dp"

android:background="#888888"

android:gravity="center"

android:text="关闭"

android:textColor="#000000" />

java代码

public class LocalSocketClientActivity extends Activity implements View.OnClickListener {

private EditText mEditText;

private LocalSocket mSocket;

private OutputStream mOut;

private static final String SOCKET_NAME = "demos.android.stormdzh.com.androiddemos.localsocket";

private static final String TAG = LocalSocketServerActivity.class.getSimpleName();

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_local_socket_client);

connect();

mEditText = (EditText) findViewById(R.id.input_msg);

findViewById(R.id.replay_btn).setOnClickListener(this);

findViewById(R.id.stop_btn).setOnClickListener(this);

}

private boolean connect() {

if (mSocket != null) {

return true;

}

try {

mSocket = new LocalSocket();//创建LocalSocket，模拟客户端

LocalSocketAddress address = new LocalSocketAddress(SOCKET_NAME,

LocalSocketAddress.Namespace.ABSTRACT);

mSocket.connect(address);//连接TestLocalSocketServer

} catch (IOException ex) {

return false;

}

return true;

}

private boolean writeCommand(String cmdString) {

final byte[] cmd = cmdString.getBytes();

final int len = cmd.length;

try {

mOut = mSocket.getOutputStream();

mOut.write(cmd, 0, len);

Log.i(TAG, "ClientActivity write " + new String(cmd));

} catch (IOException ex) {

Log.e(TAG, "ClientActivity write error:" + ex.fillInStackTrace());

return false;

}

return true;

}

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.replay_btn:

writeCommand(mEditText.getText().toString());

break;

case R.id.stop_btn:

writeCommand("stop");

break;

default:

break;

}

}

}

四、验证

首先进入到服务端页面，之后点击“去发送信息”按钮到达客户端页面，在客户端输入文本，发送即可。如果希望测试跨进程可以把客户端的Activity配置成一个单独进程：

android:process="com.localsocket.process"

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