首先选择前置后置布局效果如下功能分别是：
1、竖屏的前置，后置显示 加 拍照
2、横屏的前置，后置显示 加 拍照
整个项目的代码贴出来了，里面加了有备注，不理解的也可以去参考官网点击跳转到官网
布局代码如下：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="/apk/res/android"xmlns:app="/apk/res-auto"xmlns:tools="/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context=".MainActivity3"><TextViewandroid:layout_marginTop="20dp"android:id="@+id/textView"android:layout_width="wrap_content"android:layout_height="wrap_content"android:textSize="25sp"android:text="请选择前置后置"/><Buttonandroid:onClick="btn1"android:layout_marginTop="20dp"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="后置"/><Buttonandroid:onClick="btn2"android:layout_marginTop="20dp"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="前置"/><Buttonandroid:onClick="btn3"android:layout_marginTop="20dp"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="跳转预览页面"/></LinearLayout>
MainActivity3 处理
public class MainActivity3 extends AppCompatActivity {private TextView textView;private static int mode=1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main3);textView=findViewById(R.id.textView);if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_DENIED) {if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {requestPermissions(new String[]{Manifest.permission.CAMERA}, 11);}}}public static int getMode(){return mode;}public void btn1(View view) {mode=0;textView.setText("当前是后置");}public void btn2(View view) {mode=1;textView.setText("当前是前置");}public void btn3(View view) {startActivity(new Intent(this,MainActivity2.class));}}
预览，拍照，效果如下图：
代码布局如下：
<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="/apk/res/android"xmlns:app="/apk/res-auto"xmlns:tools="/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@color/gray"tools:context=".MainActivity2"><Buttonandroid:onClick="photograph"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="拍照"/><SurfaceViewandroid:id="@+id/surface_view"android:layout_centerInParent="true"android:layout_width="wrap_content"android:layout_height="wrap_content" /><ImageViewandroid:id="@+id/image"android:layout_alignParentBottom="true"android:layout_width="150dp"android:layout_height="150dp"/></RelativeLayout>
整个处理如下
public class MainActivity2 extends AppCompatActivity {private Camera mCamera;private boolean isPreview = false;private SurfaceView surfaceView;private ImageView image;private Bitmap bitmap;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main2);surfaceView=findViewById(R.id.surface_view);image=findViewById(R.id.image);//判断是前置还是后置if (Utils.isCurOriLand(this)){//横屏if (MainActivity3.getMode()==0){//后置surfaceView.getLayoutParams().width=640;surfaceView.getLayoutParams().height=480;}else {//前置surfaceView.getLayoutParams().width=480;surfaceView.getLayoutParams().height=640;}}else {//竖屏if (MainActivity3.getMode()==0){//后置surfaceView.getLayoutParams().width=480;surfaceView.getLayoutParams().height=640;}else {//前置surfaceView.getLayoutParams().width=640;surfaceView.getLayoutParams().height=480;}}SurfaceView mSurfaceView = (SurfaceView) findViewById(R.id.surface_view);// 获得 SurfaceHolder 对象SurfaceHolder mSurfaceHolder = mSurfaceView.getHolder();// 设置 Surface 格式// 参数： PixelFormat中定义的 int 值 ,详细参见 PixelFormat.javamSurfaceHolder.setFormat(PixelFormat.TRANSPARENT);// 如果需要，保持屏幕常亮// mSurfaceHolder.setKeepScreenOn(true);// 设置 Surface 的分辨率// mSurfaceHolder.setFixedSize(width,height);// 添加 Surface 的 callback 接口mSurfaceHolder.addCallback(mSurfaceCallback);}private SurfaceHolder.Callback mSurfaceCallback = new SurfaceHolder.Callback() {/*** 在 Surface 首次创建时被立即调用：活得叫焦点时。一般在这里开启画图的线程* @param surfaceHolder 持有当前 Surface 的 SurfaceHolder 对象*/@Overridepublic void surfaceCreated(SurfaceHolder surfaceHolder) {try {//打开硬件摄像头 这两句默认是后摄像头，如果指定摄像头用 ： Camera.open(CameraId) CameraId 0 （后置） 1 （前置）// Camera.open() 默认返回的后置摄像头信息 //导包得时候一定要注意是android.hardware.Camera// setCameraDisplayOrientation(MainActivity2.this,0,camera);//设置角度，此处 CameraId 0 （后置） 1 （前置）if (MainActivity3.getMode()==0){//后置mCamera = Camera.open(Camera.CameraInfo.CAMERA_FACING_BACK);//打开硬件摄像头，这里导包得时候一定要注意是android.hardware.CamerasetCameraDisplayOrientation( MainActivity2.this,0,mCamera);}else {//前置mCamera = Camera.open(Camera.CameraInfo.CAMERA_FACING_FRONT);//打开硬件摄像头，这里导包得时候一定要注意是android.hardware.CamerasetCameraDisplayOrientation(MainActivity2.this,1,mCamera);}//此处也可以设置摄像头参数Camera.Parameters parameters = mCamera.getParameters();//得到摄像头的参数//parameters.setPictureFormat(PixelFormat.RGB_888);//设置照片的格式parameters.setPictureFormat(PixelFormat.JPEG);//设置照片的格式parameters.setJpegQuality(85);//设置照片的质量parameters.setPreviewSize(640, 480);parameters.setPictureSize(640, 480);//设置照片的大小，默认是和屏幕一样大//parameters.setPictureSize(480, 640);//设置照片的大小，默认是和屏幕一样大mCamera.setParameters(parameters);//设置需要预览的尺寸mCamera.setPreviewDisplay(surfaceHolder);//通过SurfaceView显示取景画面 相机mCamera.setPreviewCallback(previewCallback);//预览相机mCamera.startPreview();//开始预览isPreview = true;//设置是否预览参数为真} catch (IOException e) {Log.e("TAG", e.toString());}}/*** 在 Surface 格式 和 大小发生变化时会立即调用，可以在这个方法中更新 Surface* @param surfaceHolder 持有当前 Surface 的 SurfaceHolder 对象* @param formatsurface 的新格式* @param width surface 的新宽度* @param heightsurface 的新高度*/@Overridepublic void surfaceChanged(SurfaceHolder surfaceHolder, int format, int width, int height) {}/*** 在 Surface 被销毁时立即调用：失去焦点时。一般在这里将画图的线程停止销毁* @param surfaceHolder 持有当前 Surface 的 SurfaceHolder 对象*/@Overridepublic void surfaceDestroyed(SurfaceHolder surfaceHolder) {if(mCamera != null){if(isPreview){//正在预览mCamera.stopPreview();mCamera.setPreviewCallback(null);mCamera.release();mCamera = null;}}}};private Camera.PreviewCallback previewCallback=new Camera.PreviewCallback() {@Overridepublic void onPreviewFrame(byte[] data, Camera camera) {if (Utils.isCurOriLand(getApplicationContext())) {//横屏if (MainActivity3.getMode()==0) {//后置bitmap = NV21ToBitmap.getInstance(MainActivity2.this).nv21ToBitmap(data, 640, 480, 0,false);}else {//前置bitmap = NV21ToBitmap.getInstance(MainActivity2.this).nv21ToBitmap(data, 640, 480, 90,false);}}else {if (MainActivity3.getMode()==0) {//后置bitmap = NV21ToBitmap.getInstance(MainActivity2.this).nv21ToBitmap(data, 640, 480, 90,false);}else {//前置bitmap = NV21ToBitmap.getInstance(MainActivity2.this).nv21ToBitmap(data, 640, 480, 0,true);}}}};/*** 设置 摄像头的角度* @param activity 上下文* @param cameraId 摄像头ID（假如手机有N个摄像头，cameraId 的值 就是 0 ~ N-1）* @param camera 摄像头对象*/public static void setCameraDisplayOrientation(Activity activity,int cameraId, Camera camera) {Camera.CameraInfo info = new Camera.CameraInfo();//获取摄像头信息Camera.getCameraInfo(cameraId, info);int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();//获取摄像头当前的角度int degrees = 0;switch (rotation) {case Surface.ROTATION_0:degrees = 0;break;case Surface.ROTATION_90:if (MainActivity3.getMode()==0){//后置degrees = 90;}else {degrees = 270;}break;case Surface.ROTATION_180:degrees = 180;break;case Surface.ROTATION_270:degrees = 270;break;}int result;if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {result = (info.orientation + degrees) % 360;result = (360 - result) % 360; // compensate the mirror} else {// back-facingresult = (info.orientation - degrees + 360) % 360;}camera.setDisplayOrientation(result);}public void photograph(View view) {image.setImageBitmap(bitmap);}}
一些工具类如下：
public class NV21ToBitmap {private RenderScript rs;private ScriptIntrinsicYuvToRGB yuvToRgbIntrinsic;private Type.Builder yuvType, rgbaType;private Allocation in, out;private static NV21ToBitmap nv21ToBitmap;public static NV21ToBitmap getInstance(Context context) {if (null == nv21ToBitmap) {synchronized (NV21ToBitmap.class) {nv21ToBitmap = new NV21ToBitmap(context);}}return nv21ToBitmap;}private NV21ToBitmap(Context context) {rs = RenderScript.create(context);yuvToRgbIntrinsic = ScriptIntrinsicYuvToRGB.create(rs, Element.U8_4(rs));}public Bitmap nv21ToBitmap(byte[] nv21, int width, int height , int displayOrientation,boolean isMirror) {yuvType = new Type.Builder(rs, Element.U8(rs)).setX(nv21.length);in = Allocation.createTyped(rs, yuvType.create(), Allocation.USAGE_SCRIPT);rgbaType = new Type.Builder(rs, Element.RGBA_8888(rs)).setX(width).setY(height);out = Allocation.createTyped(rs, rgbaType.create(), Allocation.USAGE_SCRIPT);in.copyFrom(nv21);yuvToRgbIntrinsic.setInput(in);yuvToRgbIntrinsic.forEach(out);Bitmap bmpout = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);out.copyTo(bmpout);Matrix matrix = new Matrix();matrix.postRotate(displayOrientation, bmpout.getWidth() / 2, bmpout.getHeight() / 2);if (isMirror) {matrix.postScale(-1.0f, 1.0f);//前置的图像是镜像的}return Bitmap.createBitmap(bmpout, 0, 0, bmpout.getWidth(), bmpout.getHeight(), matrix, true);}}public class Utils {/*** 获取当前屏幕是否是横屏（默认）** @param context* @return*/public static boolean isCurOriLand(Context context) {boolean isLand = true;try {Configuration mConfiguration = context.getResources().getConfiguration(); //获取设置的配置信息int ori = mConfiguration.orientation; //获取屏幕方向if (ori == mConfiguration.ORIENTATION_LANDSCAPE) {//横屏isLand = true;} else if (ori == mConfiguration.ORIENTATION_PORTRAIT) {//竖屏isLand = false;}} catch (Exception e) {e.printStackTrace();}return isLand;}}
