我有一个应用程序，可以在计时器上拍照。通常它工作正常，除非在相机睡眠时旋转屏幕。任何人都可以告诉我为什么它在睡眠中旋转后无法拍照？
通常情况下，当相机进入睡眠状态并唤醒时，它会执行......
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
surfaceView = (SurfaceView) findViewById(R.id.surface);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.addCallback(this);
}
@Override
protected void onStart() {
super.onStart();
}
@Override
protected void onResume() {
super.onResume();
camera = Camera.open(cameraId);
setCameraDisplayOrientation();
startCameraPreview(surfaceHolder, surfaceView.getWidth(), surfaceView.getHeight());
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
camera.stopPreview();
setCameraDisplayOrientation();
startCameraPreview(holder, w, h);
}
public void setCameraDisplayOrientation() {
deviceRotation = getWindowManager().getDefaultDisplay().getRotation();
int degrees = 0;
switch(deviceRotation) {
case Surface.ROTATION_0: degrees=0; break;//vertical
case Surface.ROTATION_90: degrees=-90; break; //left side
case Surface.ROTATION_180: degrees=180; break; //upside-down
case Surface.ROTATION_270: degrees=90; break; //right side
}
Camera.CameraInfo info = new Camera.CameraInfo();
Camera.getCameraInfo(cameraId, info);
displayRotation = info.orientation + degrees;
camera.setDisplayOrientation(displayRotation); //changes orientation of camera's display
}
public void startCameraPreview(SurfaceHolder holder, int w, int h) {
double targetRatio = 0;
switch(deviceRotation) {
case Surface.ROTATION_0: targetRatio = (double)w/(double)h; break; //vertical
case Surface.ROTATION_90: targetRatio = (double)h/(double)w; break; //left side
case Surface.ROTATION_180: targetRatio = (double)w/(double)h; break; //upside-down
case Surface.ROTATION_270: targetRatio = (double)h/(double)w; break; //right side
}
Camera.Parameters p = camera.getParameters();
List<Camera.Size> previewSizes = p.getSupportedPreviewSizes();
int optimal_h = 2; //always refers to short length in PreviewSizes
int optimal_w = 1; //always refers to long length in PreviewSizes
for(Camera.Size previewSize : previewSizes) {
if (Math.abs((double)previewSize.height/(double)previewSize.width - targetRatio) <
Math.abs((double)optimal_h/(double)optimal_w - targetRatio)) {
optimal_h = previewSize.height;
optimal_w = previewSize.width;
}
}
p.setPreviewSize(optimal_w, optimal_h); //defines ratio of image preview - sizes can be larger than actual display
p.set("rotation", displayRotation); //required to orient final jpeg file correctly
camera.setParameters(p);
ViewGroup.LayoutParams surfaceParams = surfaceView.getLayoutParams();
switch(deviceRotation) { //aligns ratio of surface view to ratio of image preview
case Surface.ROTATION_0:
surfaceParams.width=ViewGroup.LayoutParams.MATCH_PARENT;
surfaceParams.height=(int)(w*(double)optimal_w/(double)optimal_h);
break; //vertical
case Surface.ROTATION_90:
surfaceParams.width=(int)(h*(double)optimal_w/(double)optimal_h);
surfaceParams.height=ViewGroup.LayoutParams.MATCH_PARENT;
break; //left side
case Surface.ROTATION_180:
surfaceParams.width=ViewGroup.LayoutParams.MATCH_PARENT;
surfaceParams.height=(int)(w*(double)optimal_w/(double)optimal_h);
break; //upside-down
case Surface.ROTATION_270:
surfaceParams.width=(int)(h*(double)optimal_w/(double)optimal_h);
surfaceParams.height=ViewGroup.LayoutParams.MATCH_PARENT;
break; //right side
}
surfaceView.setLayoutParams(surfaceParams);
camera.setPreviewDisplay(holder); //required to startPreview
camera.startPreview();
}
然而，当相机在睡眠状态下旋转后唤醒时，它首先执行onResume（），surfaceChanged（），onPause（），onStop（空），onDestroy（空），然后执行以下操作：
import UIKit
class CustomImagePageControl: UIPageControl {
let activeImage:UIImage = UIImage(named: "SelectedPage")!
let inactiveImage:UIImage = UIImage(named: "UnselectedPage")!
override func awakeFromNib() {
super.awakeFromNib()
self.pageIndicatorTintColor = UIColor.clear
self.currentPageIndicatorTintColor = UIColor.clear
self.clipsToBounds = false
}
func updateDots() {
var i = 0
for view in self.subviews {
if let imageView = self.imageForSubview(view) {
if i == self.currentPage {
imageView.image = self.activeImage
} else {
imageView.image = self.inactiveImage
}
i = i + 1
} else {
var dotImage = self.inactiveImage
if i == self.currentPage {
dotImage = self.activeImage
}
view.clipsToBounds = false
view.addSubview(UIImageView(image:dotImage))
i = i + 1
}
}
}
fileprivate func imageForSubview(_ view:UIView) -> UIImageView? {
var dot:UIImageView?
if let dotImageView = view as? UIImageView {
dot = dotImageView
} else {
for foundView in view.subviews {
if let imageView = foundView as? UIImageView {
dot = imageView
break
}
}
}
return dot
}
}
这不是完整的代码。此代码确实产生一些次要的图像格式错误，但它仍然证明了这个问题。为简单起见，我已经删除了一些东西。主要问题是，当它在睡眠状态下旋转后尝试拍照时会返回错误＆＃34; Camera.release（）被调用后会使用相机＆＃34;。这是为什么？
答案 0 :(得分：0)
这真的是过期的，但是当我在一分钟前设法解决了我的类似问题时，我想我会为自己和其他任何可能拼命搜索Stack的人做出贡献。
因此，当您旋转设备时，您正在调用onPause和onDestroy，即释放相机。我注意到你的onResume中有camera.open（），没有看你的表面相关代码，我无法评论。这对我有用。
首先是cameraPreview
`
public void surfaceChanged(SurfaceHolder surfaceHolder, int format, int width, int height) {
try {
this.mCamera.setPreviewDisplay(surfaceHolder);
this.mCamera.startPreview();
} catch (Exception e) {
}
}
public void surfaceCreated(SurfaceHolder surfaceHolder) {
try {
//TODO we need this here too because on SurfaceCreated we always need to open the camera, in case its released
this.mCamera.setPreviewDisplay(surfaceHolder);
this.mCamera.setDisplayOrientation(90);
//this.mCamera.startPreview();
} catch (IOException e) {
}
}
接下来，CameraActivity的生命周期代码
@Override
public void onResume() {
super.onResume();
try{
mCamera = openFrontFacingCameraGingerbread();
// Add to Framelayout
this.mCameraPreview = new CameraPreview(this, this.mCamera);
mImage.removeAllViews();
this.mImage.addView(this.mCameraPreview);
}catch (RuntimeException ex){
}
}
@Override
public void onPause() {
super.onPause();
captureButton.setText("Begin Capture");
if(CameraActivity.this.timer !=null) {
CameraActivity.this.timer.cancel();
CameraActivity.this.timer.purge();
CameraActivity.this.timer = null;
}
if (mCamera != null) {
mCamera.setPreviewCallback(null);
mCameraPreview.getHolder().removeCallback(mCameraPreview);
mCamera.release();
mCamera = null;
}
}
@Override
protected void onDestroy(){
super.onDestroy();
releaseCameraAndPreview();
}
private void releaseCameraAndPreview() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
if(mCameraPreview != null){
mCameraPreview.destroyDrawingCache();
mCameraPreview.mCamera = null;
}
}