webRTC（二十）：android 截屏功能

效果

在这里插入图片描述

详细内容

主要使用MediaProjectionManager和MediaProjection

创建保存截图信息的surface

mImageReader = ImageReader.newInstance(UIUtils.getScreenWidth(this),
                UIUtils.getScreenHeight(this),
                PixelFormat.RGBA_8888,
                1);

打开系统截屏权限

projectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
Intent captureIntent = projectionManager.createScreenCaptureIntent();
        startActivityForResult(captureIntent, REQUEST_CODE);

得到返回数据


    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
            mediaProjection = projectionManager.getMediaProjection(resultCode, data);

            mVirtualDisplay = createVirtualDisplay();
            new Thread(new Runnable() {
                @Override
                public void run() {
                    //这里需要暂停100ms 否则获取不到Bitmap对象
                    SystemClock.sleep(100);
                    getScreenCapture();
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            if (mBitmap != null)
                                ((ImageView) findViewById(R.id.iv_screen)).setImageBitmap(mBitmap);
                        }
                    });
                }
            }).start();
        }
    }

生成的VirtualDisplay实例

 /**
     * name: 是生成的VirtualDisplay实例的名称；
     * width, height: 分别是生成实例的宽高，必须大于0；
     * dpi: 生成实例的像素密度，必须大于0，一般都取1；
     * surface: 这个比较重要，是你生成的VirtualDisplay的载体，
     * 我的理解是，VirtualDisplay的内容是一帧帧的屏幕截图（所以你看到是有宽高，像素密度等设置），
     * 所以MediaProjection获取到的其实是一帧帧的图，然后通过          surface（surface你可以理解成是android的一个画布，
     * 默认它会以每秒60帧来刷新，这里我们不再展开细说），来顺序播放这些图片，形成视频。
     *
     * @return
     */
    private VirtualDisplay createVirtualDisplay() {
        return mediaProjection.createVirtualDisplay("Screen",
                UIUtils.getScreenWidth(this), UIUtils.getScreenHeight(this),
                UIUtils.getScreenDpi(this),
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mImageReader.getSurface(), null /*Callbacks*/, null /*Handler*/);
    }

获取截图

/**
     * 获取截图
     *
     * @return
     */
    private boolean getScreenCapture() {
        Image image = mImageReader.acquireLatestImage();
        if (image != null) {
            int width = image.getWidth();
            int height = image.getHeight();
            final Image.Plane[] planes = image.getPlanes();
            final ByteBuffer buffer = planes[0].getBuffer();
            int pixelStride = planes[0].getPixelStride();
            int rowStride = planes[0].getRowStride();
            int rowPadding = rowStride - pixelStride * width;
            if (mBitmap == null) {
                mBitmap = Bitmap.createBitmap(width + rowPadding / pixelStride, height, Bitmap.Config.ARGB_8888);
            }
            mBitmap.copyPixelsFromBuffer(buffer);
            image.close();
            return true;
        }
        return false;
    }

全部代码

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.PixelFormat;
import android.hardware.display.DisplayManager;
import android.hardware.display.VirtualDisplay;
import android.media.Image;
import android.media.ImageReader;
import android.media.projection.MediaProjection;
import android.media.projection.MediaProjectionManager;
import android.os.Bundle;
import android.os.SystemClock;
import android.widget.ImageView;

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

import com.example.webrtcdemo.utils.UIUtils;

import java.nio.ByteBuffer;

/**
 * 截屏
 */
public class ScreenPhoneActivity extends AppCompatActivity {


    private static final int REQUEST_CODE = 102;
    private MediaProjectionManager projectionManager;
    private MediaProjection mediaProjection;
    private VirtualDisplay mVirtualDisplay;
    private ImageReader mImageReader;
    private Bitmap mBitmap;

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mVirtualDisplay == null) {
            return;
        }
        mVirtualDisplay.release();
        mVirtualDisplay = null;

        if (mediaProjection != null) {
            mediaProjection.stop();
            mediaProjection = null;
        }
        mImageReader.close();
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_cloud_phone);
        mImageReader = ImageReader.newInstance(UIUtils.getScreenWidth(this),
                UIUtils.getScreenHeight(this),
                PixelFormat.RGBA_8888,
                1);

        projectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE);
    }

    @Override
    public void onAttachedToWindow() {
        super.onAttachedToWindow();
        Intent captureIntent = projectionManager.createScreenCaptureIntent();
        startActivityForResult(captureIntent, REQUEST_CODE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
            mediaProjection = projectionManager.getMediaProjection(resultCode, data);

            mVirtualDisplay = createVirtualDisplay();
            new Thread(new Runnable() {
                @Override
                public void run() {
                    //这里需要暂停100ms 否则获取不到Bitmap对象
                    SystemClock.sleep(100);
                    getScreenCapture();
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            if (mBitmap != null)
                                ((ImageView) findViewById(R.id.iv_screen)).setImageBitmap(mBitmap);
                        }
                    });
                }
            }).start();
        }
    }

    /**
     * name: 是生成的VirtualDisplay实例的名称；
     * width, height: 分别是生成实例的宽高，必须大于0；
     * dpi: 生成实例的像素密度，必须大于0，一般都取1；
     * surface: 这个比较重要，是你生成的VirtualDisplay的载体，
     * 我的理解是，VirtualDisplay的内容是一帧帧的屏幕截图（所以你看到是有宽高，像素密度等设置），
     * 所以MediaProjection获取到的其实是一帧帧的图，然后通过          surface（surface你可以理解成是android的一个画布，
     * 默认它会以每秒60帧来刷新，这里我们不再展开细说），来顺序播放这些图片，形成视频。
     *
     * @return
     */
    private VirtualDisplay createVirtualDisplay() {
        return mediaProjection.createVirtualDisplay("Screen",
                UIUtils.getScreenWidth(this), UIUtils.getScreenHeight(this),
                UIUtils.getScreenDpi(this),
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mImageReader.getSurface(), null /*Callbacks*/, null /*Handler*/);
    }

    /**
     * 获取截图
     *
     * @return
     */
    private boolean getScreenCapture() {
        Image image = mImageReader.acquireLatestImage();
        if (image != null) {
            int width = image.getWidth();
            int height = image.getHeight();
            final Image.Plane[] planes = image.getPlanes();
            final ByteBuffer buffer = planes[0].getBuffer();
            int pixelStride = planes[0].getPixelStride();
            int rowStride = planes[0].getRowStride();
            int rowPadding = rowStride - pixelStride * width;
            if (mBitmap == null) {
                mBitmap = Bitmap.createBitmap(width + rowPadding / pixelStride, height, Bitmap.Config.ARGB_8888);
            }
            mBitmap.copyPixelsFromBuffer(buffer);
            image.close();
            return true;
        }
        return false;
    }
}


    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />
    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
    <uses-permission android:name="android.permission.RECORD_AUDIO" />
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

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webRTC（二十）：android 截屏功能

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