Android Camera2video使用前置摄像头

Question

我想弄清楚如何设置camera2video使用前置摄像头。我新的Android开发，并试图找出这一点。

Answer 1

如果前方照相机确实存在，并返回其ID（-1，如果不存在的话）

private int findFrontFacingCamera() { 
     int cameraId = -1; 
     // Search for the front facing camera 
     int numberOfCameras = Camera.getNumberOfCameras(); 
     for (int i = 0; i < numberOfCameras; i++) { 
      Camera.CameraInfo info = new Camera.CameraInfo(); 
      Camera.getCameraInfo(i, info); 
      if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) { 
       Log.d("CAMERA", "Camera found"); 
       cameraId = i; 
       break; 
      } 
     } 
     return cameraId; 
    } 

这块方法将帮助ü使用您的前置摄像头这种方法发现：

private void useFrontFacingCamera() { 
     if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) { 

      Toast.makeText(this, "No camera on this device", Toast.LENGTH_LONG).show(); 

     } else { 
      cameraId = findFrontFacingCamera(); 
      if (cameraId < 0) { 
       Toast.makeText(this, "No front facing camera found.",Toast.LENGTH_LONG).show(); 
      } else { 

       camera = Camera.open(cameraId); 
       camera.unlock(); 

      } 
    } 

//in my case i have to use frontal camera to make a scan on a qr code : 

    IntentIntegrator scanIntegrator = new IntentIntegrator(this); 
    scanIntegrator.setCameraId(cameraId); // <-- use this method to use your camera 

    scanIntegrator.initiateScan(); 
} 

重要提示：如果您想在其他活动中使用您的相机，请不要忘记以下方法：

@Override 
    protected void onPause() { 

     if (camera != null) { 
      camera.stopPreview(); 
      camera.release(); 
      camera = null; 
      Log.d("camera", "releaseCamera -- done"); 
     } 
     super.onPause(); 
    } 
    @Override 
    protected void onResume() { 

     if (camera != null) { 

      Camera.open(); 
      Log.d("camera", "openCamera -- done"); 
     } 

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

     super.onStart(); 
    } 
    @Override 
    protected void onStop() { 
     super.onStop(); 
     if (camera != null) { 
      camera.stopPreview(); 
      camera.release(); 
      camera = null; 
      Log.e("camera", "releaseCamera -- done"); 
     } 
    }