en android, reproduzca la vista previa de la cámara en una vista

Question

Quiero transmitir la vista previa de la cámara android, a una vista. La intención es agregar varias cosas a la vista posteriormente, usando onDraw(). No necesito capturar la imagen en ningún momento. No tiene que ser de la más alta calidad o con el mayor número de cuadros por segundo. ¿Alguien tiene una idea de cómo se puede hacer esto?

Answer 1

agregar esto a su xml:

<SurfaceView 
    android:id="@+id/camerapreview" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
/> 

---

en su clase de actividad:

private Preview mPreview; 
Camera mCamera; 
int numberOfCameras; 
int cameraCurrentlyLocked; 
int defaultCameraId; 

---

onCreate-Método:

mPreview = new Preview(this); 
setContentView(mPreview); 

mPreview.setOnClickListener(new OnClickListener() { 
    @Override 
    public void onClick(View v) { 
     mCamera.autoFocus(null); 
    } 
}); 

---

@Override 
protected void onPause() { 
    super.onPause(); 

    // Because the Camera object is a shared resource, it's very 
    // important to release it when the activity is paused. 
    if (mCamera != null) { 
     mPreview.setCamera(null); 
     mCamera.release(); 
     mCamera = null; 
    } 
} 

---

@Override 
protected void onResume() { 
    super.onResume(); 

    // Open the default i.e. the first rear facing camera. 
    mCamera = Camera.open(); 
    cameraCurrentlyLocked = defaultCameraId; 
    mPreview.setCamera(mCamera); 
} 

---

y la clase previsualización:

public class Preview extends ViewGroup implements SurfaceHolder.Callback { 
    private final String TAG = "Preview"; 

    SurfaceView mSurfaceView; 
    SurfaceHolder mHolder; 
    Size mPreviewSize; 
    List<Size> mSupportedPreviewSizes; 
    Camera mCamera; 

    public Preview(Context context) { 
     super(context); 

     mSurfaceView = new SurfaceView(context); 
     addView(mSurfaceView); 

     // Install a SurfaceHolder.Callback so we get notified when the 
     // underlying surface is created and destroyed. 
     mHolder = mSurfaceView.getHolder(); 
     mHolder.addCallback(this); 
     mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 
    } 

    public void setCamera(Camera camera) { 
     mCamera = camera; 
     if (mCamera != null) { 
      mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes(); 
      requestLayout(); 
     } 
    } 

    public void switchCamera(Camera camera) { 
     setCamera(camera); 
     try { 
      camera.setPreviewDisplay(mHolder); 
     } catch (IOException exception) { 
      Log.e(TAG, "IOException caused by setPreviewDisplay()", exception); 
     } 
     Camera.Parameters parameters = camera.getParameters(); 
     parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height); 
     requestLayout(); 

     camera.setParameters(parameters); 
    } 

    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
     // We purposely disregard child measurements because act as a 
     // wrapper to a SurfaceView that centers the camera preview instead 
     // of stretching it. 
     final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec); 
     final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec); 
     setMeasuredDimension(width, height); 

     if (mSupportedPreviewSizes != null) { 
      mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height); 
     } 
    } 

    @Override 
    protected void onLayout(boolean changed, int l, int t, int r, int b) { 
     if (changed && getChildCount() > 0) { 
      final View child = getChildAt(0); 

      final int width = r - l; 
      final int height = b - t; 

      int previewWidth = width; 
      int previewHeight = height; 
      if (mPreviewSize != null) { 
       previewWidth = mPreviewSize.width; 
       previewHeight = mPreviewSize.height; 
      } 

      // Center the child SurfaceView within the parent. 
      if (width * previewHeight > height * previewWidth) { 
       final int scaledChildWidth = previewWidth * height/previewHeight; 
       child.layout((width - scaledChildWidth)/2, 0, 
         (width + scaledChildWidth)/2, height); 
      } else { 
       final int scaledChildHeight = previewHeight * width/previewWidth; 
       child.layout(0, (height - scaledChildHeight)/2, 
         width, (height + scaledChildHeight)/2); 
      } 
     } 
    } 

    public void surfaceCreated(SurfaceHolder holder) { 
     // The Surface has been created, acquire the camera and tell it where 
     // to draw. 
     try { 
      if (mCamera != null) { 
       mCamera.setPreviewDisplay(holder); 
      } 
     } catch (IOException exception) { 
      Log.e(TAG, "IOException caused by setPreviewDisplay()", exception); 
     } 
    } 

    public void surfaceDestroyed(SurfaceHolder holder) { 
     // Surface will be destroyed when we return, so stop the preview. 
     if (mCamera != null) { 
      mCamera.stopPreview(); 
     } 
    } 


    private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) { 
     final double ASPECT_TOLERANCE = 0.1; 
     double targetRatio = (double) w/h; 
     if (sizes == null) return null; 

     Size optimalSize = null; 
     double minDiff = Double.MAX_VALUE; 

     int targetHeight = h; 

     // Try to find an size match aspect ratio and size 
     for (Size size : sizes) { 
      double ratio = (double) size.width/size.height; 
      if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue; 
      if (Math.abs(size.height - targetHeight) < minDiff) { 
       optimalSize = size; 
       minDiff = Math.abs(size.height - targetHeight); 
      } 
     } 

     // Cannot find the one match the aspect ratio, ignore the requirement 
     if (optimalSize == null) { 
      minDiff = Double.MAX_VALUE; 
      for (Size size : sizes) { 
       if (Math.abs(size.height - targetHeight) < minDiff) { 
        optimalSize = size; 
        minDiff = Math.abs(size.height - targetHeight); 
       } 
      } 
     } 
     return optimalSize; 
    } 

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { 
     // Now that the size is known, set up the camera parameters and begin 
     // the preview. 
     if(mCamera != null){ 
      Camera.Parameters parameters = mCamera.getParameters(); 
      parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height); 
      requestLayout(); 

      mCamera.setParameters(parameters); 
      mCamera.startPreview(); 
     } 
    } 

}