在几台Android设备上延伸的相机预览

3 回答

• 16

  使用 getOptimalPreviewSize() 很重要，但它并不能解决所有布局中所有设备的所有拉伸问题 . 您必须准备好稍微裁剪预览，以便预览填充屏幕而不会失真 .

  有不同的技术来强制表面的大小不同于实际的屏幕尺寸，但这个我觉得最容易：

  我将 CameraView 添加到我的布局中：

  public class CameraView extends SurfaceView implements SurfaceHolder.Callback {
  
  public CameraView(Context context, AttributeSet attr) {
      super(context, attr);
  
      // install a SurfaceHolder.Callback so we get notified when the
      // underlying surface is created and destroyed.
      getHolder().addCallback(this);
  }
  
  @Override public void surfaceCreated(SurfaceHolder holder) {
      openCamera();
      bCameraInitialized = false;
  }
  
  @Override public void surfaceDestroyed(SurfaceHolder holder) {
      camera.release();
  }
  
  @Override public void surfaceChanged(SurfaceHolder holder,
          int format, int w, int h) {
          if (bCameraInitialized) {
              // we will get here after we have resized the surface, see below 
              return;
          }
          cameraSetup(w, h);
          bCameraInitialized = true;
  }
  
  private void cameraSetup(int w, int h) {
      // set the camera parameters, including the preview size
  
      FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) getLayoutParams();
      double cameraAspectRatio = ((double)optimalSize.width)/optimalSize.height;
  
      if (((double)h)/w > cameraAspectRatio) {
          lp.width = (int)(h/cameraAspectRatio+0.5);
          lp.height = h;
      }
      else {
          lp.height = (int)(w*cameraAspectRatio + 0.5);
          lp.width = w;
          lp.topMargin = (h - lp.height)/2;
      }
      lp.gravity = Gravity.CENTER_HORIZONTAL | Gravity.TOP;
  
      setLayoutParams(lp);
      requestLayout();
  }
  

  为了强调主要思想，我没有包含错误处理，而且我这里没有显示相机如何is actually started with a secondary Looper .

  回复于 2024-05-12T19:20:03+08:00
• 0

  您需要覆盖SurfaceView类的onMeasure方法以获取surfaceview的宽度和高度

  @Override
      protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
          final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
          final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
          setMeasuredDimension(width, height);
  
          if (mSupportedPreviewSizes != null) {
              mPreviewSize = getOptimalPreviewSize(mCamera.getParameters().getSupportedPreviewSizes(), width, height);
          }
      }
  

  然后将您获得的预览大小设置为相机参数预览大小 .

  cameraParameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
  mCamera.setParameters(cameraParameters);
  

  getSuggestedMinimumHeight（），getSuggestedMinimumWidth（）是View类的方法

  希望这可以帮助 ！！！

  回复于 2024-05-12T19:20:03+08:00
• 1

  试试这个它正在工作......

  public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
  
  private static final String TAG = "Camera Preview";
  private static final double PREVIEW_SIZE_FACTOR = 3.00;
  private SurfaceHolder mHolder = null;
  private Camera mCamera = null;
  Camera.Parameters _parameters=null;
  
  @SuppressWarnings("deprecation")
  public CameraPreview(Context context, Camera camera) {
      super(context);
      mCamera = camera;
      // Install a SurfaceHolder.Callback so we get notified when the
      // underlying surface is created and destroyed.
      mHolder = getHolder();
      mHolder.addCallback(this);
      // deprecated setting, but required on Android versions prior to 3.0
      mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
  }
  
  public void surfaceCreated(SurfaceHolder holder) {
      // The Surface has been created, now tell the camera where to draw the preview.
      try {
          Camera.Parameters parameters = mCamera.getParameters();
          final Size mPreviewSize = getOptimalSize();
          parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
           requestLayout();
          mCamera.setParameters(parameters);
          mCamera.setPreviewDisplay(holder);
          mCamera.startPreview();
          //startContinuousAutoFocus();
      } catch (Exception e) {
          Log.d(TAG, "Error setting camera preview: " + e.getMessage());
      }
  }
  public void surfaceDestroyed(SurfaceHolder holder) {
  }
  
  @SuppressLint("NewApi")
  public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
      // If your preview can change or rotate, take care of those events here.
      // Make sure to stop the preview before resizing or reformatting it.
  
      if (mHolder.getSurface() == null){
          // preview surface does not exist
          return;
      }
  
      // stop preview before making changes
      try {
          mCamera.stopPreview();
      } catch (Exception e){
          // ignore: tried to stop a non-existent preview
      }
  
      // set preview size and make any resize, rotate or
      // reformatting changes here
      // set Camera parameters
  
      // start preview with new settings
      try {
          mCamera.setPreviewDisplay(mHolder);
          mCamera.startPreview();
  
      } catch (Exception e){
          Log.d(TAG, "Error starting camera preview: " + e.getMessage());
      }
      }
  public void startPreview(){
      try{
          mCamera.startPreview();
      }catch (Exception e) {
      }
          } 
          private Size getOptimalSize() {
      Camera.Size result = null;
      final Camera.Parameters parameters = mCamera.getParameters();
      Log.i(CameraPreview.class.getSimpleName(), "window width: " + getWidth() + ", height: " + getHeight());
      for (final Camera.Size size : parameters.getSupportedPreviewSizes()) {
          if (size.width <= getWidth() * PREVIEW_SIZE_FACTOR && size.height <= getHeight() * PREVIEW_SIZE_FACTOR) {
              if (result == null) {
                  result = size;
              } else {
                  final int resultArea = result.width * result.height;
                  final int newArea = size.width * size.height;
  
                  if (newArea > resultArea) {
                      result = size;
                  }
              }
          }
      }
      if (result == null) {
          result = parameters.getSupportedPreviewSizes().get(0);
      }
      Log.i(CameraPreview.class.getSimpleName(), "Using PreviewSize: " + result.width + " x " + result.height);
      return result;
  }
  }
  

  回复于 2024-05-12T19:20:03+08:00