camera startPreview failed
17,774
Solution 1
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());
}
}
So the error must be in i one of these lines:
Parameters parameters= mCamera.getParameters();
parameters.setPreviewSize(w, h);
mCamera.setParameters(parameters);
Someone could explain me what was wrong in those lines?
Solution 2
Is (w, h) a valid preview size for your camera?
You can use mCamera.getParameters().getSupportedPreviewSizes()
to get all of the valid preview sizes.
Solution 3
Its late, but if someones looking for the answer
The variables w and h are not the optimal preview sizes . You can get optimal preview sizes using the function
public static Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio=(double)h / w;
if (sizes == null) return null;
Camera.Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
for (Camera.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);
}
}
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Camera.Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
and you can call the function using
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
..
size=getOptimalPreviewSize(parameters.getSupportedPreviewSizes(), w, h);
parameters.setPreviewSize(size.getWidth(), size.getHeight());
..
}
Solution 4
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.getParameters().getSupportedPreviewSizes();
mCamera.startPreview();
Log.d(TAG, "Camera preview started.");
} catch (IOException e) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
Author by
user1805792
Updated on July 19, 2022Comments
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user1805792 almost 2 years
I am creating a camera app but I have problems on
startPreview
, it sends me:java.lang.RuntimeException: startPreview failed
here is my camera Activity:
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; } }}
And here is my SurfaceView code:
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()); } } }
And here is my error log:
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)
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Alex Cohn over 10 yearsThis is most likely the reason of the
RuntimeException
. For some devices, call to Camera.setParameters() with unsupported preview size can causeRuntimeException
. For others, the exception is thrown on Camera.startPreview() -
hybrid over 8 yearsI have posted the answer below.