I'm creating the preview for camera, I created it successfully but sometime it stretch the preview so I search on google and stackoverflow and found some solution that is getting best supportedPreviewSize from camera and show it.
Here is some code that I'm using but there is error.
java.lang.NullPointerException: Attempt to read from field 'int android.hardware.Camera$Size.width' on a null object reference
I know this error is due to null reference, My question is way this is null ?
Preview
public class Preview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceView mSurfaceView;
public Preview(Context ctx, SurfaceView surfaceView) {
super(ctx);
init(surfaceView);
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
Log.i(TAG, "surfaceCreated");
this.start();
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
Log.i(TAG, "surfaceChanged");
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height); // Here is error
mCamera.setParameters(parameters);
mCamera.startPreview();
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.i(TAG, "onMeasure");
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
}
private 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;
}
private void init(SurfaceView surfaceView){
mSurfaceView = surfaceView;
final SurfaceHolder surfaceHolder = mSurfaceView.getHolder();
surfaceHolder.addCallback(this);
}
public void setCamera(){
mCamera = Camera.open()
}
public void start(){
if(mCamera != null){
try {
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
mCamera.setPreviewDisplay(mSurfaceView.getHolder());
mCamera.startPreview();
} catch (IOException e) {
e.printStackTrace();
}
}
}
// other code...
MainActivity
Preview preview;
SurfaceView surfaceView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
preview = new Preview(this, surfaceView);
}
#Override
protected void onResume() {
super.onResume();
preview.setCamera();
preview.start();
}
// other code
activity_main.xml
<com.azeem.mycamera.Preview
android:id="#+id/surfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
Why I'm getting this error What I'm missing please let me know.
Related
When i try to record using my custom camera its preview showing normally and in good shape but when i click on start button preview changed and stretching.
public class MyCameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder mHolder;
private Camera mCamera;
private List<Camera.Size> mSupportedPreviewSizes;
private Camera.Size mPreviewSize;
private int mRatioWidth = 0;
private int mRatioHeight = 0;
public MyCameraSurfaceView(Context context, Camera camera) {
super(context);
mCamera = camera;
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
for(Camera.Size str: mSupportedPreviewSizes)
Log.e("Ji", str.width + "/" + str.height);
setKeepScreenOn(true);
// 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);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int weight,
int height) {
// 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();
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
mCamera.setParameters(parameters);
mCamera.setDisplayOrientation(90);
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
// The Surface has been created, now tell the camera where to draw the preview.
try {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
mCamera.setParameters(parameters);
mCamera.setDisplayOrientation(90);
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (IOException e) {
}
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
Here is onMesuare method for calculations
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
if (0 == mRatioWidth || 0 == mRatioHeight) {
setMeasuredDimension(width, height);
} else {
if (width < height * mRatioWidth / mRatioHeight) {
setMeasuredDimension(width, width * mRatioHeight / mRatioWidth);
} else {
setMeasuredDimension(height * mRatioWidth / mRatioHeight, height);
}
}
And For getting Size of Screen here is method.
private 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.height / size.width;
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;
}
}
Thanks for help in advance...
I have created a CameraSurfaceView class which provides logic for implementing the camera preview. Everything works fine on the devices I have tried. Nexus 5, Nexus 5X, Nexus 6P and even a Samsung Galaxy S5.
But for some reason on the Samsung Galaxy S6 Edge, I get a Runtime exception of
android.hardware.Camera.native_setParameters(Native Method)
I have narrowed it down to the the following in class
parameters.setPictureSize(mPreviewSize.width, mPreviewSize.height);
Here is my class:
public class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback {
private Camera mCamera;
private SurfaceHolder mSurfaceHolder;
private List<Camera.Size> mSupportedPreviewSizes;
private Camera.Size mPreviewSize;
public CameraSurfaceView(Context context, Camera camera) {
super(context);
mCamera = camera;
mSurfaceHolder = getHolder();
mSurfaceHolder.addCallback(this);
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (mSurfaceHolder.getSurface() == null) {
// preview surface does not exist
return;
}
try {
// stop preview before making changes
mCamera.stopPreview();
} catch (Exception e) {
Timber.e(e, e.getMessage());
}
// set preview size and make any resize, rotate or reformatting changes here
// start preview with new settings
try {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
parameters.setPictureSize(mPreviewSize.width, mPreviewSize.height);
if (parameters.getSupportedFocusModes()
.contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
}
mCamera.setParameters(parameters);
mCamera.setPreviewDisplay(mSurfaceHolder);
mCamera.startPreview();
} catch (Exception e) {
Timber.e(e, "Error starting camera preview: " + e.getMessage());
}
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
float ratio;
if (mPreviewSize.height >= mPreviewSize.width) {
ratio = (float) mPreviewSize.height / (float) mPreviewSize.width;
} else {
ratio = (float) mPreviewSize.width / (float) mPreviewSize.height;
}
// One of these methods should be used, second method squishes preview slightly
setMeasuredDimension(width, (int) (width * ratio));
// setMeasuredDimension((int) (width * ratio), height);
}
private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
final double aspectTolerance = 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.height / size.width;
if (Math.abs(ratio - targetRatio) > aspectTolerance) {
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;
}
}
How do I set the picture size correctly for this device or any others with the same issue?
Does anyone have a good example of Camera SurfaceView logic that would work for most devices?
Thanks.
Turns out I was using the supportedPreviewSizes to set the picture size as opposed to the supportedPictureSizes in the camera parameters.
Below is my new CameraSurfaceView class:
public class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback {
private Camera mCamera;
private SurfaceHolder mSurfaceHolder;
private List<Camera.Size> mSupportedPreviewSizes;
private List<Camera.Size> mSupportedPictureSizes;
private Camera.Size mPreviewSize;
private Camera.Size mPictureSize;
public CameraSurfaceView(Context context, Camera camera) {
super(context);
mSurfaceHolder = getHolder();
mSurfaceHolder.addCallback(this);
mCamera = camera;
Camera.Parameters parameters = mCamera.getParameters();
mSupportedPreviewSizes = parameters.getSupportedPreviewSizes();
mSupportedPictureSizes = parameters.getSupportedPictureSizes();
if (parameters.getSupportedFocusModes()
.contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
}
mCamera.setParameters(parameters);
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (mSurfaceHolder.getSurface() == null) {
// preview surface does not exist
return;
}
try {
// stop preview before making changes
mCamera.stopPreview();
} catch (Exception e) {
Timber.e(e, e.getMessage());
}
// set preview size and make any resize, rotate or reformatting changes here
// start preview with new settings
try {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
parameters.setPictureSize(mPictureSize.width, mPictureSize.height);
mCamera.setParameters(parameters);
mCamera.setPreviewDisplay(mSurfaceHolder);
mCamera.startPreview();
} catch (Exception e) {
Timber.e(e, "Error starting camera preview: " + e.getMessage());
}
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
if (mSupportedPictureSizes != null) {
mPictureSize = getOptimalPreviewSize(mSupportedPictureSizes, mPreviewSize.width,
mPreviewSize.height);
}
float ratio;
if (mPreviewSize.height >= mPreviewSize.width) {
ratio = (float) mPreviewSize.height / (float) mPreviewSize.width;
} else {
ratio = (float) mPreviewSize.width / (float) mPreviewSize.height;
}
setMeasuredDimension(width, (int) (width * ratio));
}
private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
final double aspectTolerance = 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.height / size.width;
if (Math.abs(ratio - targetRatio) > aspectTolerance) {
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;
}
}
I've implemented a custom camera activity in my app. The camera works pretty well on my nexus 5. However on an Alcatel One Touch Star, when I stop the preview to show the snapshot, I get this preview
Furthermore, the byte array of the PictureCallback is correct. Infact, if I decode the array into a Bitmap, I can see it correctly.
Here is my implementation of the SurfaceView as camera preview.
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
private int mPhotoRotation;
public CameraPreview(Context context) {
super(context);
}
#SuppressLint("InlinedApi")
#SuppressWarnings("deprecation")
public CameraPreview(Context context, Camera camera) {
super(context);
mCamera = camera;
Camera.Parameters parameters = camera.getParameters();
List<String> focusModes = parameters.getSupportedFocusModes();
if (focusModes != null && focusModes.contains(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE))
parameters.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
else if (focusModes != null && focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO))
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
if (parameters.getSupportedFlashModes() != null && parameters.getSupportedFlashModes().contains(Parameters.FLASH_MODE_AUTO))
parameters.setFlashMode(Parameters.FLASH_MODE_AUTO);
camera.setParameters(parameters);
mHolder = getHolder();
mHolder.addCallback(this);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB)
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
}
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (mCamera != null) {
mCamera.stopPreview();
Parameters parameters = mCamera.getParameters();
List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();
Camera.Size size = getOptimalPreviewSize(previewSizes, width, height);
parameters.setPreviewSize(size.width, size.height);
mCamera.setParameters(parameters);
Display display = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
mPhotoRotation = 0;
if (display.getRotation() == Surface.ROTATION_0) {
mPhotoRotation = 90;
} else if (display.getRotation() == Surface.ROTATION_270) {
mPhotoRotation = 180;
}
mCamera.setDisplayOrientation(mPhotoRotation);
mCamera.startPreview();
}
}
private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) h / w;
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;
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
public int getPhotoRotation() {
return mPhotoRotation;
}
}
When the user take the photo, this code is executed
mCamera.takePicture(null, null, mPictureCallback);
and the callback just keep a backup of the byte array and stop the preview.
mPictureCallback = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
mPhotoJpeg = data;
mCamera.stopPreview();
}
};
So what is the cause of this behaviour? Why only on an alcatel and not on the nexus 5?
I have a small issue with the camera in my application. When i am in preview mode and i lock my phone then unlock it the preview is stuck to the image that was on preview before locking... any idea why this is happening?
I have done some research and i have created my activity class. This is working perfectly when my manifest looks like this:
<activity
android:name="ro.gebs.captoom.activities.TakePicture"
android:screenOrientation="landscape"
android:theme="#android:style/Theme.NoTitleBar.Fullscreen">
</activity>
but is not working when i have android:screenOrientation="portrait"
Here is the full code:
public class TakePicture extends Activity { //implements FinishTakePictureCallback {
private SurfaceView preview = null;
private SurfaceHolder previewHolder = null;
private Camera camera = null;
private boolean inPreview = false;
private boolean cameraConfigured = false;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
//requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.camera_control);
preview = (SurfaceView) findViewById(R.id.preview);
previewHolder = preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
#Override
public void onResume() {
super.onResume();
camera = Camera.open();
startPreview();
}
#Override
public void onPause() {
if (inPreview) {
camera.stopPreview();
}
camera.release();
camera = null;
inPreview = false;
super.onPause();
}
private Camera.Size getBestPreviewSize(int width, int height,
Camera.Parameters parameters) {
Camera.Size result = null;
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
if (size.width <= width && size.height <= height) {
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
int newArea = size.width * size.height;
if (newArea > resultArea) {
result = size;
}
}
}
}
return (result);
}
private void initPreview(int w, int h) {
if (camera != null && previewHolder.getSurface() != null) {
try {
camera.setPreviewDisplay(previewHolder);
} catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback",
"Exception in setPreviewDisplay()", t);
Utils.showToast(TakePicture.this, t.getMessage(), Toast.LENGTH_SHORT);
}
if (!cameraConfigured) {
Camera.Parameters parameters = camera.getParameters();
List<Size> sizes = parameters.getSupportedPreviewSizes();
for (Size size : sizes) {
Log.d("TakePicture", size.height + "X" + size.width + "height" + h + "width" + w);
}
Size optimalSize = getOptimalPreviewSize(sizes, h, w);
parameters.setPreviewSize(optimalSize.width, optimalSize.height);
camera.setDisplayOrientation(90);
camera.setParameters(parameters);
cameraConfigured = true;
}
}
}
private void startPreview() {
if (cameraConfigured && camera != null) {
camera.startPreview();
inPreview = true;
}
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) w / h;
if (sizes == null)
return null;
Log.d("TakePicture", "TargetRatio: " + targetRatio);
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
continue;
if (Math.abs(size.height - h) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - h);
}
}
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - h) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - h);
}
}
}
Log.d("TakePicture", "The optimal size is:" + optimalSize.height + "X" + optimalSize.width);
return optimalSize;
}
SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
public void surfaceCreated(SurfaceHolder holder) {
// no-op -- wait until surfaceChanged()
}
public void surfaceChanged(SurfaceHolder holder,
int format, int width,
int height) {
initPreview(width, height);
startPreview();
}
public void surfaceDestroyed(SurfaceHolder holder) {
// no-op
}
};
}
Thanks in advance.
I want to stream the camera preview of the android camera, onto a view. The intention is to afterwards add various things to the view, using onDraw(). I don't need to actually capture the image at any time.
It doesn't have to be in the highest quality or largest number of frames per second.
Does anyone have an idea how this can be done?
add this to your xml:
<SurfaceView
android:id="#+id/camerapreview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
into your activity-class:
private Preview mPreview;
Camera mCamera;
int numberOfCameras;
int cameraCurrentlyLocked;
int defaultCameraId;
onCreate-Method:
mPreview = new Preview(this);
setContentView(mPreview);
mPreview.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
mCamera.autoFocus(null);
}
});
#Override
protected void onPause() {
super.onPause();
// Because the Camera object is a shared resource, it's very
// important to release it when the activity is paused.
if (mCamera != null) {
mPreview.setCamera(null);
mCamera.release();
mCamera = null;
}
}
#Override
protected void onResume() {
super.onResume();
// Open the default i.e. the first rear facing camera.
mCamera = Camera.open();
cameraCurrentlyLocked = defaultCameraId;
mPreview.setCamera(mCamera);
}
and the preview-class:
public class Preview extends ViewGroup implements SurfaceHolder.Callback {
private final String TAG = "Preview";
SurfaceView mSurfaceView;
SurfaceHolder mHolder;
Size mPreviewSize;
List<Size> mSupportedPreviewSizes;
Camera mCamera;
public Preview(Context context) {
super(context);
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = mSurfaceView.getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void setCamera(Camera camera) {
mCamera = camera;
if (mCamera != null) {
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
requestLayout();
}
}
public void switchCamera(Camera camera) {
setCamera(camera);
try {
camera.setPreviewDisplay(mHolder);
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
camera.setParameters(parameters);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// We purposely disregard child measurements because act as a
// wrapper to a SurfaceView that centers the camera preview instead
// of stretching it.
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
if (changed && getChildCount() > 0) {
final View child = getChildAt(0);
final int width = r - l;
final int height = b - t;
int previewWidth = width;
int previewHeight = height;
if (mPreviewSize != null) {
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
}
// Center the child SurfaceView within the parent.
if (width * previewHeight > height * previewWidth) {
final int scaledChildWidth = previewWidth * height / previewHeight;
child.layout((width - scaledChildWidth) / 2, 0,
(width + scaledChildWidth) / 2, height);
} else {
final int scaledChildHeight = previewHeight * width / previewWidth;
child.layout(0, (height - scaledChildHeight) / 2,
width, (height + scaledChildHeight) / 2);
}
}
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
try {
if (mCamera != null) {
mCamera.setPreviewDisplay(holder);
}
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
if (mCamera != null) {
mCamera.stopPreview();
}
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) w / h;
if (sizes == null) return null;
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Try to find an size match aspect ratio and size
for (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);
}
}
// Cannot find the one match the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
if(mCamera != null){
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
mCamera.setParameters(parameters);
mCamera.startPreview();
}
}
}