Android相机踩坑

Camera.release() 用完了必须release否则会导致用相机失败

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If your application does not properly release the camera,
all subsequent attempts to access the camera,
including those by your own application, will fail and may cause your or other applications to be shut do

检查相机是否存在

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/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}

接入相机,允许相机存在

If you have determined that the device on which your application is running has a camera, you must request to access it by getting an instance ofCamera
(unless you are using an intent to access the camera).

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/** A safe way to get an instance of the Camera object. */
public static Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}

Camera.open(int),多个相机使用这个

获取相机信息

Camera.getParameters()相机信息
Camera.getCameraInfo()前后摄像头

相机界面

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/** A basic Camera preview class */
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;

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 {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}

public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
}

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

// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();

} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}

如果想改变surfaceView的大小可调用 surfaceChanged()
获取surfaceView大小用getSupportedPreviewSizes()
setDisplayOrientation()该边相机方向(方位/位置)在surfaceChanged里面去做

照相机方向

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private void setRightCameraOrientation(int cameraId, Camera mCamera) {

Camera.CameraInfo info = new android.hardware.Camera.CameraInfo();
Camera.getCameraInfo(cameraId, info);

int rotation = ((OSPhotoActivity)mContext).getWindowManager().getDefaultDisplay().getRotation();
int degrees = 0;
switch (rotation) {
case Surface.ROTATION_0:
degrees = 0;
break;
case Surface.ROTATION_90:
degrees = 90;
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-facing
result = (info.orientation - degrees + 360) % 360;
}
mCamera.setDisplayOrientation(result);
}

自动对焦

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mCamera.autoFocus(autoFocusCallback);

谢谢您的鼓励~