android设备间实现无线投屏的示例代码

目录

• 前言
• 投屏服务端的实现
• 投屏客户端的实现
• 效果
• 遇到的错误

前言

Android提供了MediaProjection来实现录屏，通过MediaProjection可以获取当前屏幕的视频流，而视频流需要通过编解码来压缩进行传输，通过MediaCodec可实现视频的编码和解码。视频流的推送和接收可通过Socket或WebSocket来实现，服务端推送编码的视频流，客户端接收视频流并进行解码，然后渲染在SurfaceView上即可显示服务端的画面。

投屏服务端的实现

服务端主入口负责请求录屏和启动录屏服务，服务端主入口的实现如下：

package com.example.screenprojection;
import android.content.Intent;
import android.media.projection.MediaProjectionManager;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
  private static final int PROJECTION_REQUEST_CODE = 1;
  private MediaProjectionManager mediaProjectionManager;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    init();
  }
  private void init() {
    mediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
  }
  public void onClick(View view) {
    if (view.getId() == R.id.btn_start) {
      startProjection();
    }
  }
  // 请求开始录屏
  private void startProjection() {
    Intent intent = mediaProjectionManager.createScreenCaptureIntent();
    startActivityForResult(intent, PROJECTION_REQUEST_CODE);
  }
  @Override
  protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode != RESULT_OK) {
      return;
    }
    if (requestCode == PROJECTION_REQUEST_CODE) {
      Intent service = new Intent(this, ScreenService.class);
      service.putExtra("code", resultCode);
      service.putExtra("data", data);
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        startForegroundService(service);
      } else {
        startService(service);
      }
    }
  }
  @Override
  protected void onDestroy() {
    super.onDestroy();
  }
}

Android8.0后录屏需要开启前台服务通知，录屏服务开启后同时启动WebSocketServer服务端，前台服务代码如下：

package com.example.screenprojection;
import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.graphics.BitmapFactory;
import android.media.projection.MediaProjection;
import android.media.projection.MediaProjectionManager;
import android.os.Build;
import android.os.IBinder;
public class ScreenService extends Service {
  private MediaProjectionManager mMediaProjectionManager;
  private SocketManager mSocketManager;
  @Override
  public void onCreate() {
    super.onCreate();
    mMediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
    createNotificationChannel();
  }
  @Override
  public int onStartCommand(Intent intent, int flags, int startId) {
    int resultCode = intent.getIntExtra("code", -1);
    Intent resultData = intent.getParcelableExtra("data");
    startProject(resultCode, resultData);
    return super.onStartCommand(intent, flags, startId);
  }
  // 录屏开始后进行编码推流
  private void startProject(int resultCode, Intent data) {
    MediaProjection mediaProjection = mMediaProjectionManager.getMediaProjection(resultCode, data);
    if (mediaProjection == null) {
      return;
    }
    // 初始化服务器端
    mSocketManager = new SocketManager();
    mSocketManager.start(mediaProjection);
  }
  private void createNotificationChannel() {
    Notification.Builder builder = new Notification.Builder(this.getApplicationContext());
    Intent nfIntent = new Intent(this, MainActivity.class);
    builder
        .setContentIntent(PendingIntent.getActivity(this, 0, nfIntent, 0))
        .setLargeIcon(
            BitmapFactory.decodeResource(
                this.getResources(), R.mipmap.ic_launcher)) // 设置下拉列表中的图标(大图标)
        .setSmallIcon(R.mipmap.ic_launcher) // 设置状态栏内的小图标
        .setContentText("is running......") // 设置上下文内容
        .setWhen(System.currentTimeMillis()); // 设置该通知发生的时间
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
      builder.setChannelId("notification_id");
      // 前台服务notification适配
      NotificationManager notificationManager =
          (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
      NotificationChannel channel =
          new NotificationChannel(
              "notification_id", "notification_name", NotificationManager.IMPORTANCE_LOW);
      notificationManager.createNotificationChannel(channel);
    }
    Notification notification = builder.build();
    notification.defaults = Notification.DEFAULT_SOUND; // 设置为默认通知音
    startForeground(110, notification);
  }
  @Override
  public IBinder onBind(Intent intent) {
    return null;
  }
  @Override
  public void onDestroy() {
    mSocketManager.close();
    super.onDestroy();
  }
}

SocketManager为WebSocketServer的控制类，并同时将录屏对象MediaProjection与视频编码器ScreenEncoder绑定。

package com.example.screenprojection;
import android.media.projection.MediaProjection;
import java.net.InetSocketAddress;
public class SocketManager {
  private static final String TAG = SocketManager.class.getSimpleName();
  private static final int SOCKET_PORT = 50000;
  private final ScreenSocketServer mScreenSocketServer;
  private ScreenEncoder mScreenEncoder;
  public SocketManager() {
    mScreenSocketServer = new ScreenSocketServer(new InetSocketAddress(SOCKET_PORT));
  }
  public void start(MediaProjection mediaProjection) {
    mScreenSocketServer.start();
    mScreenEncoder = new ScreenEncoder(this, mediaProjection);
    mScreenEncoder.startEncode();
  }
  public void close() {
    try {
      mScreenSocketServer.stop();
      mScreenSocketServer.close();
    } catch (InterruptedException e) {
      e.printStackTrace();
    }
    if (mScreenEncoder != null) {
      mScreenEncoder.stopEncode();
    }
  }
  public void sendData(byte[] bytes) {
    mScreenSocketServer.sendData(bytes);
  }
}

推流服务端ScreenSocketServer代码如下：

package com.example.screenprojection;
import android.util.Log;
import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;
import java.net.InetSocketAddress;
public class ScreenSocketServer extends WebSocketServer {
  private final String TAG = ScreenSocketServer.class.getSimpleName();
  private WebSocket mWebSocket;
  public ScreenSocketServer(InetSocketAddress inetSocketAddress) {
    super(inetSocketAddress);
  }
  @Override
  public void onOpen(WebSocket conn, ClientHandshake handshake) {
    Log.d(TAG, "onOpen");
    mWebSocket = conn;
  }
  @Override
  public void onClose(WebSocket conn, int code, String reason, boolean remote) {
    Log.d(TAG, "onClose:" + reason);
  }
  @Override
  public void onMessage(WebSocket conn, String message) {}
  @Override
  public void onError(WebSocket conn, Exception ex) {
    Log.d(TAG, "onError:" + ex.toString());
  }
  @Override
  public void onStart() {
    Log.d(TAG, "onStart");
  }
  public void sendData(byte[] bytes) {
    if (mWebSocket != null && mWebSocket.isOpen()) {
      // 通过WebSocket 发送数据
      Log.d(TAG, "sendData:");
      mWebSocket.send(bytes);
    }
  }
  public void close() {
    mWebSocket.close();
  }
}

WebSocketServer启动成功会回调onStart方法。

       @Override
       public void onStart() {
            Log.d(TAG, "onStart");
       }

当有客户端连接回调onOpen方法，通过回调的WebSocket对象即可向客户端发送数据。

      @Override
      public void onOpen(WebSocket conn, ClientHandshake handshake) {
          Log.d(TAG, "onOpen");
          mWebSocket = conn;
      }

视频编码器ScreenEncoder采用采用H.265编码（H.265/HEVC），需要注意不同手机支持的编码最大分辨率不同。

package com.example.screenprojection;
import android.hardware.display.DisplayManager;
import android.media.MediaCodec;
import android.media.MediaCodecInfo;
import android.media.MediaFormat;
import android.media.projection.MediaProjection;
import android.view.Surface;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
 * 采用H.265编码 H.265/HEVC的编码架构大致上和H.264/AVC的架构相似 H.265又称为HEVC(全称High Efficiency Video Coding，高效率视频编码)
 */
public class ScreenEncoder extends Thread {
  //不同手机支持的编码最大分辨率不同
  private static final int VIDEO_WIDTH = 2160;
  private static final int VIDEO_HEIGHT = 3840;
  private static final int SCREEN_FRAME_RATE = 20;
  private static final int SCREEN_FRAME_INTERVAL = 1;
  private static final long SOCKET_TIME_OUT = 10000;
  // I帧
  private static final int TYPE_FRAME_INTERVAL = 19;
  // vps帧
  private static final int TYPE_FRAME_VPS = 32;
  private final MediaProjection mMediaProjection;
  private final SocketManager mSocketManager;
  private MediaCodec mMediaCodec;
  private boolean mPlaying = true;
  // 记录vps pps sps
  private byte[] vps_pps_sps;
  public ScreenEncoder(SocketManager socketManager, MediaProjection mediaProjection) {
    mSocketManager = socketManager;
    mMediaProjection = mediaProjection;
  }
  public void startEncode() {
    MediaFormat mediaFormat =
        MediaFormat.createVideoFormat(MediaFormat.MIMETYPE_VIDEO_HEVC, VIDEO_WIDTH, VIDEO_HEIGHT);
    mediaFormat.setInteger(
        MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface);
    // 比特率（比特/秒）
    mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, VIDEO_WIDTH * VIDEO_HEIGHT);
    // 帧率
    mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, SCREEN_FRAME_RATE);
    // I帧的频率
    mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, SCREEN_FRAME_INTERVAL);
    try {
      mMediaCodec = MediaCodec.createEncoderByType(MediaFormat.MIMETYPE_VIDEO_HEVC);
      mMediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
      Surface surface = mMediaCodec.createInputSurface();
      mMediaProjection.createVirtualDisplay(
          "screen",
          VIDEO_WIDTH,
          VIDEO_HEIGHT,
          1,
          DisplayManager.VIRTUAL_DISPLAY_FLAG_PUBLIC,
          surface,
          null,
          null);
    } catch (IOException e) {
      e.printStackTrace();
    }
    start();
  }
  @Override
  public void run() {
    mMediaCodec.start();
    MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
    while (mPlaying) {
      int outPutBufferId = mMediaCodec.dequeueOutputBuffer(bufferInfo, SOCKET_TIME_OUT);
      if (outPutBufferId >= 0) {
        ByteBuffer byteBuffer = mMediaCodec.getOutputBuffer(outPutBufferId);
        encodeData(byteBuffer, bufferInfo);
        mMediaCodec.releaseOutputBuffer(outPutBufferId, false);
      }
    }
  }
  private void encodeData(ByteBuffer byteBuffer, MediaCodec.BufferInfo bufferInfo) {
    int offSet = 4;
    if (byteBuffer.get(2) == 0x01) {
      offSet = 3;
    }
    int type = (byteBuffer.get(offSet) & 0x7E) >> 1;
    if (type == TYPE_FRAME_VPS) {
      vps_pps_sps = new byte[bufferInfo.size];
      byteBuffer.get(vps_pps_sps);
    } else if (type == TYPE_FRAME_INTERVAL) {
      final byte[] bytes = new byte[bufferInfo.size];
      byteBuffer.get(bytes);
      byte[] newBytes = new byte[vps_pps_sps.length + bytes.length];
      System.arraycopy(vps_pps_sps, 0, newBytes, 0, vps_pps_sps.length);
      System.arraycopy(bytes, 0, newBytes, vps_pps_sps.length, bytes.length);
      mSocketManager.sendData(newBytes);
    } else {
      byte[] bytes = new byte[bufferInfo.size];
      byteBuffer.get(bytes);
      mSocketManager.sendData(bytes);
    }
  }
  public void stopEncode() {
    mPlaying = false;
    if (mMediaCodec != null) {
      mMediaCodec.release();
    }
    if (mMediaProjection != null) {
      mMediaProjection.stop();
    }
  }
}

注意点：
1.需要依赖WebSocket相关jar。

implementation “org.java-websocket:Java-WebSocket:1.5.3”

2.AndroidManifest配置网络和前台服务权限。

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

3.配置前台录屏服务foregroundServiceType属性。

    <service
            android:name=".ScreenService"
            android:enabled="true"
            android:exported="true"
            android:foregroundServiceType="mediaProjection" />

投屏客户端的实现

客户端入口负责创建SurfaceView并初始化WebSocket客户端管理器SocketClientManager。

package com.example.screenplayer;

import android.os.Bundle;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

  private SocketClientManager mSocketClientManager;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    SurfaceView surfaceView = findViewById(R.id.sv_screen);
    surfaceView
        .getHolder()
        .addCallback(
            new SurfaceHolder.Callback() {
              @Override
              public void surfaceCreated(@NonNull SurfaceHolder holder) {
                // 连接到服务端
                initSocketManager(holder.getSurface());
              }

              @Override
              public void surfaceChanged(
                  @NonNull SurfaceHolder holder, int format, int width, int height) {}

              @Override
              public void surfaceDestroyed(@NonNull SurfaceHolder holder) {}
            });
  }

  private void initSocketManager(Surface surface) {
    mSocketClientManager = new SocketClientManager();
    mSocketClientManager.start(surface);
  }

  @Override
  protected void onDestroy() {
    if (mSocketClientManager != null) {
      mSocketClientManager.stop();
    }
    super.onDestroy();
  }
}

SocketClientManager将Surface与解码器绑定，创建WebSocket客户端并接收服务端推送的视频流。其中URI 需要修改为服务端的IP地址和端口。

package com.example.screenplayer;
import android.view.Surface;
import java.net.URI;
import java.net.URISyntaxException;
public class SocketClientManager implements ScreenSocketClient.SocketCallback {
  private static final int SOCKET_PORT = 50000;
  private ScreenDecoder mScreenDecoder;
  private ScreenSocketClient mSocketClient;
  public void start(Surface surface) {
    mScreenDecoder = new ScreenDecoder();
    mScreenDecoder.startDecode(surface);
    try {
      // 需要修改为服务端的IP地址与端口
      URI uri = new URI("ws://192.168.1.3:" + SOCKET_PORT);
      mSocketClient = new ScreenSocketClient(this, uri);
      mSocketClient.connect();
    } catch (URISyntaxException e) {
      e.printStackTrace();
    }
  }
  public void stop() {
    if (mSocketClient != null) {
      mSocketClient.close();
    }
    if (mScreenDecoder != null) {
      mScreenDecoder.stopDecode();
    }
  }
  @Override
  public void onReceiveData(byte[] data) {
    if (mScreenDecoder != null) {
      mScreenDecoder.decodeData(data);
    }
  }
}

ScreenSocketClient代码如下：

package com.example.screenplayer;
import android.util.Log;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;
import java.net.URI;
import java.nio.ByteBuffer;
public class ScreenSocketClient extends WebSocketClient {
  private static final String TAG = ScreenSocketClient.class.getSimpleName();
  private final SocketCallback mSocketCallback;
  public ScreenSocketClient(SocketCallback socketCallback, URI serverUri) {
    super(serverUri);
    mSocketCallback = socketCallback;
  }
  @Override
  public void onOpen(ServerHandshake serverHandshake) {
    Log.d(TAG, "onOpen");
  }
  @Override
  public void onMessage(String message) {}
  @Override
  public void onMessage(ByteBuffer bytes) {
    byte[] buf = new byte[bytes.remaining()];
    bytes.get(buf);
    if (mSocketCallback != null) {
      mSocketCallback.onReceiveData(buf);
    }
  }
  @Override
  public void onClose(int code, String reason, boolean remote) {
    Log.d(TAG, "onClose =" + reason);
  }
  @Override
  public void onError(Exception ex) {
    Log.d(TAG, "onError =" + ex.toString());
  }
  public interface SocketCallback {
    void onReceiveData(byte[] data);
  }
}

不同手机支持的解码最大分辨率不同，需要设置正确的分辨率才不会报错。投屏解码器ScreenDecoder代码如下：

package com.example.screenplayer;
import android.media.MediaCodec;
import android.media.MediaFormat;
import android.view.Surface;
import java.io.IOException;
import java.nio.ByteBuffer;
public class ScreenDecoder {
  private static final int VIDEO_WIDTH = 2160;
  private static final int VIDEO_HEIGHT = 3840;
  private static final long DECODE_TIME_OUT = 10000;
  private static final int SCREEN_FRAME_RATE = 20;
  private static final int SCREEN_FRAME_INTERVAL = 1;
  private MediaCodec mMediaCodec;
  public ScreenDecoder() {}
  public void startDecode(Surface surface) {
    try {
      // 配置MediaCodec
      mMediaCodec = MediaCodec.createDecoderByType(MediaFormat.MIMETYPE_VIDEO_HEVC);
      MediaFormat mediaFormat =
          MediaFormat.createVideoFormat(MediaFormat.MIMETYPE_VIDEO_HEVC, VIDEO_WIDTH, VIDEO_HEIGHT);
      mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, VIDEO_WIDTH * VIDEO_HEIGHT);
      mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, SCREEN_FRAME_RATE);
      mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, SCREEN_FRAME_INTERVAL);
      mMediaCodec.configure(mediaFormat, surface, null, 0);
      mMediaCodec.start();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  public void decodeData(byte[] data) {
    int index = mMediaCodec.dequeueInputBuffer(DECODE_TIME_OUT);
    if (index >= 0) {
      ByteBuffer inputBuffer = mMediaCodec.getInputBuffer(index);
      inputBuffer.clear();
      inputBuffer.put(data, 0, data.length);
      mMediaCodec.queueInputBuffer(index, 0, data.length, System.currentTimeMillis(), 0);
    }
    MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
    int outputBufferIndex = mMediaCodec.dequeueOutputBuffer(bufferInfo, DECODE_TIME_OUT);
    while (outputBufferIndex > 0) {
      mMediaCodec.releaseOutputBuffer(outputBufferIndex, true);
      outputBufferIndex = mMediaCodec.dequeueOutputBuffer(bufferInfo, 0);
    }
  }
  public void stopDecode() {
    if (mMediaCodec != null) {
      mMediaCodec.release();
    }
  }
}

注意点：
1.需要依赖WebSocket相关jar。

implementation “org.java-websocket:Java-WebSocket:1.5.3”

2.AndroidManifest配置网络权限。

<uses-permission android:name="android.permission.INTERNET"/>

效果

左手边为服务端，右手边为客户端，服务端投屏到客户端的效果如下：

遇到的错误

1.WebSocket出现Permission denied的报错：

onerror =java.net.SocketException: socket failed: EACCES (Permission denied)

问题原因：需要网络权限。

<uses-permission android:name=“android.permission.INTERNET”/>

2.WebSocket出现Host unreachable报错：

onerror =java.net.NoRouteToHostException: Host unreachable

问题原因：不在同一局域网内或服务端未正常启动。

3.WebSocket出现failed to connect报错：

failed to connect to /192.168.1.3 (port 50000) from /:: (port 38262):，不在同一局域网内或服务端未正常启动

问题原因：不在同一局域网内或服务端未正常启动。

客户端连接成功回调onOpen方法

      @Override
      public void onOpen(ServerHandshake handshakedata) {
           Log.d(TAG,"SocketClient onOpen");
      }

4.初始化MediaFormat时报IllegalStateException异常：

Caused by: java.lang.IllegalArgumentException
at android.media.MediaCodec.native_configure(Native Method)
at android.media.MediaCodec.configure(MediaCodec.java:2023)
at android.media.MediaCodec.configure(MediaCodec.java:1951)
at com.example.screenprojection.ScreenEncoder.startEncode(ScreenEncoder.java:56)

问题原因：不同手机支持的最大编解码分辨率不同，可通过adb shell cat /system/etc/media_codecs.xml的adb命令查看手机支持的编解码分辨率。未设置编码强制要求的一些配置 会抛出 IllegalStateException。

       <MediaCodec name="OMX.hisi.video.decoder.hevc.secure" type="video/hevc" >
            <Quirk name="needs-flush-on-all-ports" />
            <Limit name="size" min="128x128" max="4096x2304" />
            <Limit name="alignment" value="2x2" />
            <Limit name="block-size" value="16x16" />
            <Limit name="block-count" range="64-36896" />
            <Limit name="blocks-per-second" range="99-1106880" />
            <Limit name="bitrate" range="1-52428800" />
            <Feature name="adaptive-playback" />
            <Feature name="secure-playback" required="true" />
            <Quirk name="requires-allocate-on-input-ports" />
            <Quirk name="requires-allocate-on-output-ports" />
            <Limit name="concurrent-instances" max="1" />
        </MediaCodec>

        <!--config suggestion for hevc -->
        <!--VT:1280x720@1Mbps@30fps，640x360@450kpbps@30fps,640x360@250kbps@30fps，640x360@170kbps@15fps-->
        <!--DestkTop Share: 1280x720@500kbps@3-7fps,720x450@200kbps@3-7fps-->
        <!--Wifi Display:1920x1080@8Mbps@30fps 4Kx2k@27M@30fps-->
        <!--Recoding:1920x1080@12Mbps@30fps，4k2k@30Mbps@30fps,1920x1080@40M@120fps，1280X720@40M@120fps-->
        <MediaCodec name="OMX.hisi.video.encoder.hevc" type="video/hevc" >
            <Limit name="size" min="176x144" max="3840x2160" />
            <Limit name="alignment" value="4x4" />
            <Limit name="block-size" value="64x64" />
            <Limit name="blocks-per-second" range="99-244800" />
            <Limit name="bitrate" range="200000-70000000" />
            <Quirk name="requires-allocate-on-output-ports" />
            <Limit name="concurrent-instances" max="3" />
        </MediaCodec>

源码下载地址：无线投屏源码，百度网盘下载地址如下：

链接: https://pan.baidu.com/s/1YQ6UHpUuLOMjp7Wf9DmvSw 提取码: crri 

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