相机启动预览失败 [英] camera startPreview failed
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问题描述
我正在创建一个相机应用程序，但我在 startPreview 上遇到问题，它发送给我:
I am creating a camera app but I have problems on startPreview, it sends me:
java.lang.RuntimeException: startPreview failed
这是我的相机活动:
public class CameraActivity extends Activity {
private Camera mCamera;
private CameraPreview mPreview;
private Target_Frame targetFrame;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.camera_layout);
mCamera=getCameraInstance();
mPreview=new CameraPreview(this, mCamera);
FrameLayout preview=(FrameLayout)findViewById(R.id.camera_preview);
preview.addView(mPreview);
}
/** Check if this device has a camera only if not specified in the manifest */
public 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;
}
}
/** 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
}
/**Check if the device has flash*/
public boolean checkFlash(Context context){
if(context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)){
//the device has flash
return true;
}else{
//no flash
return false;
}
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
releaseCamera();
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
releaseCamera();
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
//Test if i have to put all this code like in onCreate
if(mCamera!=null){
return;
}
mCamera=getCameraInstance();
if(mPreview!=null){
return;
}
mPreview=new CameraPreview(this, mCamera);
FrameLayout preview=(FrameLayout)findViewById(R.id.camera_preview);
preview.addView(mPreview);
}
private void releaseCamera(){
if (mCamera != null){
mCamera.release(); // release the camera for other applications
mCamera = null;
}
}}
这是我的 SurfaceView 代码:
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "CameraPreview";
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
Parameters parameters= mCamera.getParameters();
parameters.setPreviewSize(w, h);
mCamera.setParameters(parameters);
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
这是我的错误日志:
12-01 13:17:01.135: E/AndroidRuntime(1161): FATAL EXCEPTION: main
12-01 13:17:01.135: E/AndroidRuntime(1161): java.lang.RuntimeException: startPreview
12-01 13:17:01.135: E/AndroidRuntime(1161): at com.example.prueba.CameraPreview.surfaceCreated(CameraPreview.java:36)
推荐答案
我已经解决了删除surfaceChanged中的一些行
I have solved deleting some lines in surfaceChanged
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.
Log.d("Function", "surfaceChanged iniciado");
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());
}
}
所以错误必须在这些行之一中:
So the error must be in i one of these lines:
Parameters parameters= mCamera.getParameters();
parameters.setPreviewSize(w, h);
mCamera.setParameters(parameters);
有人可以解释一下这些行有什么问题吗?
Someone could explain me what was wrong in those lines?
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