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Delay after taking photo Android camera app

I am creating a basic camera app as a small project I'm doing to get started with Android development.
When I click on the button to take a picture, there is about a 1-second delay in which the preview freezes before unfreezing again. There is no issue with crashing - just the freezing issue. Why is this happening and how can I fix it?
Below is the method where the camera is instantiated, as well as my SurfaceView class.
private void startCamera() {
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
cameraPreviewLayout = (FrameLayout) findViewById(R.id.camera_preview);
camera = checkDeviceCamera();
camera.setDisplayOrientation(90);
mImageSurfaceView = new ImageSurfaceView(MainActivity.this, camera);
cameraPreviewLayout.addView(mImageSurfaceView);
ImageButton captureButton = (ImageButton)findViewById(R.id.imageButton);
captureButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
camera.takePicture(null, null, pictureCallback);
camera.stopPreview();
camera.startPreview();
}
});
}
public class ImageSurfaceView extends SurfaceView implements
SurfaceHolder.Callback {
private Camera camera;
private SurfaceHolder surfaceHolder;
public ImageSurfaceView(Context context, Camera camera) {
super(context);
this.camera = camera;
this.surfaceHolder = getHolder();
this.surfaceHolder.addCallback(this);
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
try {
this.camera.setPreviewDisplay(holder);
this.camera.startPreview();
this.camera.setDisplayOrientation(90);
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
}
EDIT: There is currently nothing in the pictureCallback.
Camera.PictureCallback pictureCallback = new Camera.PictureCallback() {
}

You don't need to call stopPreview() after takePicture(). And you don't need startPreview() on the next line. You do need startPreview() inside your onPictureTaken() callback (not in onClick() as in the posted code!!) if you want live preview to restart after the picture is captured into a Jpeg stream.
To keep your UI responsive while using camera, you should do all work with the camera on a background thread. But it is not enough to call Camera.open() or Camera.close() on some background thread. You must create a Handler thread and use it for Camera.open(). The same Looper will be used for all camera callbacks, including PictureCallback.onPictureTaken(). See my detailed walkthrough about the use of HandlerThread.
As I explained elsewhere, you can achieve even better performance if you use the new camera2 API on devices that fully support this API (but better use the old API with devices that provide only LEGACY level of camera2 support).
But if you want to get maximum from the camera ISP, this kind of freeze may be inevitable (this depends on many hardware and firmware design choices, made by the manufacturer). Some clever UI tweaks may help to conceal this effect.

You’ll need to enable access to the hidden “Developer options” menu on
your Android phone. To do that, simply tap the “About phone” option in
Settings. Then tap “Build number” seven times and you’re done. Now you
can just back out to the main Settings menu and you’ll find Developer
options somewhere near the bottom of the list.
==>Now that you’re done with that part, let the real fun begins. Tap the new Developer options menu you just enabled and scroll until you
see the following three settings (note that they may be located within
an “Advanced” subsection):
Window animation scale Transition animation scale Animator animation
scale
==>Did you see them? By default, each of those three options is set to “1x” but tapping them and changing them to “.5x” will dramatically
speed up your phone. This harmless tweak forces the device to speed up
all transition animations, and the entire user experience is faster
and smoother as a result

Is there a way to use flashlight on in Android NOT using the Camera methods?

Please read the question before marking this as a duplicate. I'm trying to access the LED/Flashlight WITHOUT using the Camera methods shown in other code on this site. Thank you.
I'm trying to use the flashlight/torch in Android. I have found and implemented code that works for doing this. The problem I have is that I'm using an image recognition API that uses the camera as an image scanner and they don't have a light on/off function. When I try to override their methods and use the Camera methods to turn the torch on/off, this works, however, the Camera methods now control the window and their Scanner no longer has priority on the screen.
So what I'm trying to determine is... Is there another way to turn on the flashlight/torch without using the Camera methods and preview functions. Anyone have an idea how to bypass the Camera to use the flashlight/torch? Any information would be greatly appreciated.
Here is the code that I currently use, which is working to turn the flashlight on/off, but like I said...this overrides the scanner, and I need the camera/scanner to operate at the same time to recognize my images.
public class Flashlight extends AutoScannerSession {
Camera cam;
private CameraManager mCameraManager;
private Context context;
private Scanner scanner;
private AutoScannerSession.Listener listener;
private boolean advancedListener = false;
public Flashlight(Activity parent, Scanner scanner, Listener listener, SurfaceView preview) {
super(parent, scanner, listener, preview);
cam = Camera.open();
cam.setErrorCallback(new Camera.ErrorCallback() {
#Override
public void onError(int error, Camera camera) {
Log.e("erro", error +"");
}
});
this.context = parent;
this.mCameraManager = new CameraManager(parent, this, preview);
this.scanner = scanner;
this.listener = listener;
if(listener instanceof AutoScannerSession.AdvancedListener) {
this.advancedListener = true;
}
}
#Override
public void start() {
super.start();
//flashOn();
}
public void flashOn() {
android.hardware.Camera.Parameters p = cam.getParameters();
p.setFlashMode(android.hardware.Camera.Parameters.FLASH_MODE_TORCH);
cam.setParameters(p);
//cam.startPreview();
}
public void flashOff() {
cam.stopPreview();
cam.release();
}
#Override
public void stop() {
super.stop();
flashOff();
}

No there is no alternative way to work with flash. But probably you can "share" the camera object with the Scanner.
At any rate, Camera.open() in Activity.onCreate() and turning on flashlight in Activity.onStart() do not look correct. To be a good citizen among other apps, your app should not obtain camera before onResume() and release it no later than onPause().

Code Snippet to turn on camera flash light.
Camera cam = Camera.open();
Parameters p = cam.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
cam.setParameters(p);
cam.startPreview();
Code snippet to turn off camera led light.
cam.stopPreview();
cam.release();

I have a Symphony H20 smartphone officially running Android 4.4.2, Kernel 3.4.67, MT6582. Setting Parameters.FLASH_MODE_TORCH as a camera parameter did not work. After trying a few hours I decided to decompile its pre-installed FlashLight app. There, I found that they write 1 in file /sys/class/torch/torch/torch_level to turn on the Camera LED and 0 to turn it off.
Then I tried the same thing and voilla! It worked.
But the same technique did not work in my Winmax W800 Plus with Android 4.4.2, Kernel 3.4.67, MT6572. It even does not have a file like /sys/class/torch/torch/torch_level at all.

Turn on/off camera flashlight on Android

Is it possible to switch between on and off multiple times in a short time the camera flashlight of an Android device? If so, how?
I am trying to create an app that is able to send data over the flashlight blinks.

To do it in code, use this link.
Basically you use the camera flash in the following manner:
private Camera camera;
Parameters params;
private void turnOnFlash() {
params = camera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(params);
camera.startPreview();
}
}

Making android camera app using Camera API that will work on all devices

I know, this question was asked maaany times, but I do not think there was a solution for this. I'm developing application which should be targeted for all devices with android system and backfacing camera. The problem is I can test application on only two devices and have to be sure that it works on all devices.I think only reasonable solution would be to to find a code samples for camera api that are quaranteed to work on nearly all devices. Does anybody can provide such sources ... but sources ... that really are tested on maaaaany (ALL) devices ? I've lost all hairs from my head ... and .. and I'm loosing my mind i think... It is all because I've released app (only for tests in my company) which was tested on only two devices, and which uses camera api in a way that should work, but it appears there are some phones like for example HTC desire HD or HTC Evo 3d (with 3d camera) where the app simply crashes (because of fu..ing camera) or freezes (also because of fu..ing camera). If there is someone who have sources for camera api (taking a picture without user gui interaction, periodically) which are really tested, please be so kind and if You can, post the source or redirect me to proper place.
Hmm maybe The question should sound like this: "Is it technically possible to use camera api on all devices ?"
Maybe I will describe how I'm currently using api.
1) Initialize cam:
public void initCam()
{
LoggingFacility.debug("Attempting to initialize camera",this);
LoggingFacility.debug("Preview is enabled:"+isPreview,this);
try {
if (camera==null)
{
camera = Camera.open();
camera.setPreviewDisplay(mHolder);
if (camera!=null)
{
Camera.Parameters parameters = camera.getParameters();
List<Size> sizes = parameters.getSupportedPictureSizes();
if (sizes!=null)
{
Size min = sizes.get(0);
for (Size size : sizes)
if (size.width<min.width) min = size;
{
parameters.setPictureSize(min.width, min.height);
}
}
camera.setParameters(parameters);
setDisplayOrientation(90);
}
}
startPreview(aps);
} catch (Throwable e){
if (exceptionsCallback!=null)
exceptionsCallback.onException(e);
}
}
2) Start preview:
private void startPreview(AfterPreviewStarted after)
{
try {
if (!isPreview)
{
LoggingFacility.debug("Starting preview",this);
//camera.stopPreview();
camera.startPreview();
isPreview = true;
LoggingFacility.debug("Preview is enabled:"+isPreview,this);
}
if (after!=null) after.doAfter();
}catch(Throwable e)
{
if (exceptionsCallback!=null)
exceptionsCallback.onException(e);
}
}
3) Take picture:
public void takePicture(final PictureCallback callback)
{
LoggingFacility.debug("Attempting to take a picture",this);
if (camera!=null)
{
if (isPreview)
{
try
{
LoggingFacility.debug("preview is enabled jut before taking picture",this);
//AudioManager mgr = (AudioManager)ctx.getSystemService(Context.AUDIO_SERVICE);
//mgr.setStreamMute(AudioManager.STREAM_SYSTEM, true);
LoggingFacility.debug("Taking picture... preview will be stopped...",this);
isPreview = false;
camera.takePicture(null, new PictureCallback(){
public void onPictureTaken(byte[] arg0, Camera arg1)
{
//LoggingFacility.debug("Picture has been taken - 1t callback",CameraPreview.this);
}
}, callback);
//mgr.setStreamMute(AudioManager.STREAM_SYSTEM, false);
} catch (Throwable e){
if (exceptionsCallback!=null)
exceptionsCallback.onException(e);
}
}
}
4) Release camera after done, or after surface is disposed.
public void releaseCam()
{
LoggingFacility.debug("Attempting to release camera",this);
if (camera!=null)
{
isTakingPictures = false;
camera.stopPreview();
isPreview = false;
camera.release();
camera = null;
LoggingFacility.debug("A camera connection has been released...",this);
}
}
In 3rd code snippet in callback method Im invoking startPreview again since after taking picture a preview is disabled, and some smartphones require preview to be started to make a picture. All above method are part of class extending SurfaceView and implementing SurfaceHolder.Callback and is a part of activity.
SurfaceHolder.Callback is implemented as follows:
public void surfaceCreated(SurfaceHolder holder) {
initCam();
}
public void surfaceDestroyed(SurfaceHolder holder) {
releaseCam();
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
}
Constructor of class
CameraPreview(Context context) {
super(context);
this.ctx = context;
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
I was also considering another approach - to overcome taking picture, and instead of this to register onPreviewFrame callback and for example in this callback check the flag if a picture has been requested, if so - convert image to bitmap and use it in further processing. I was trying this approach, but then stuck with another problem - even If I register empty callback, a gui responds much slower.
For everyone who like me have problems using android camera api please refer to this link . It seems the code from this sample works on majority of smartphones.

final int PICTURE_TAKEN = 1;
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
intent.putExtra(MediaStore.EXTRA_VIDEO_QUALITY, 1);
intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(new File(filename)));
startActivityForResult(intent, PICTURE_TAKEN);
This works for me, haven't had complaints sofar.

How to set android lock screen image

I'm just getting started with android programming, and want to see if there is a way to programmatically set the lock screen image. I've found various ways of setting the wallpaper in the API, but I can't seem to find the equivalent ways of setting the lock screen image.
I've seen various posts saying that customising the lock screen by adding widgets or bits of applications is not possible, but surely there must be a way to set the image programmatically?
Cheers,
Robin

As of API Level 24 they have added new methods (and updated the documentation) and flags to the WallpaperManager which allow you to set a Wallpaper not only to the home screen but also to the Lockscreen
To set a Wallpaper to the Lockscreen use the new flag WallpaperManager.FLAG_LOCK, and one of the methods which take int which
WallpaperManager.getInstance(this).setStream(inputStream, null, true, WallpaperManager.FLAG_LOCK);
You can also use one of the following methods
int setStream (InputStream bitmapData, Rect visibleCropHint, boolean allowBackup, int which)
int setResource (int resid, int which)
int setBitmap (Bitmap fullImage, Rect visibleCropHint, boolean allowBackup, int which)
A nice addition is that you can now also check if you are allowed to set the wallpaper via isSetWallpaperAllowed, and get the current set wallpaper via getWallpaperFile
Check out the updated documentation for the WallpaperManager.

There is no "lock screen image" in Android. There most certainly is no "lock screen image" concept that is the same between stock Android, HTC Sense, MOTOBLUR, etc. This simply is not part of the Android SDK.
The project that Mr. Rijk points to is a security violation that pretends to be a lock screen replacement.

There is a way to do it on Samsung devices. In the intent you can put an extra.
intent.putExtra("SET_LOCKSCREEN_WALLPAPER", true);
startActivity(intent);
I've only tested this on some Samsung phones and there's no guarantee that this won't break some time in the future. Use with caution.

You can use these three methods of WalpaperManager class but it will only work for nought version devices or above it:-
public int setBitmap (Bitmap fullImage,
Rect visibleCropHint,
boolean allowBackup,
int which)
public int setResource (int resid,
int which)
public int setStream (InputStream inputStreamData,
Rect visibleCropHint,
boolean allowBackup,
int which)
Parameter of these three methods:-
Bitmap/resid/inputStreamData :-this parameter accept data
visibleCropHint:-this parameter accept Rect object which is mainly used for Cropping functionality, for more information refer to Android developer reference website, you can also pass null if u don't want cropping functionality
allowBackup:-boolean: true if the OS is permitted to back up this wallpaper image for restore to a future device; false otherwise.
which:-It is one of the most important parameter which helps you to configure wallpaper for lock screen and home wallpaper. for lock screen use WalpaperManager.FLAG_LOCK and for home wallpaper use FLAG_SYSTEM
I am giving one example to make you understand how to use it:-
WalaperManager wm = WalaperManager.getInstance();
try {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
wm.setBitmap(bitmap,null,true,WalpaperManager.FLAG_LOCK);//For Lock screen
Toast.makeText(context.context, "done", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(context.context, "Lock screen walpaper not supported",
Toast.LENGTH_SHORT).show();
}
} catch (e: Exception) {
Toast.makeText(context.context, e.message, Toast.LENGTH_SHORT).show();
}
for more information visit Android developer wallpaper manager reference

There is another way to do this. at first ,you need save the pic which you wanna set in lockedscreen in a folder(suppose it's called "appName").and then ,use following code to open gallery, after gallery has opened.lead user to open "appName" folder ,and choose the pic in gallery of system. in the gallery,user can set a pic as wallpaper or lockscreen paper.
// this code to open gallery.
startActivity(new Intent(Intent.ACTION_SET_WALLPAPER));

Bitmap icon = BitmapFactory.decodeResource(getViewContext().getResources(), R.drawable.wall);
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {
WallpaperManager wallpaperManager = WallpaperManager.getInstance(getViewContext());
try {
wallpaperManager.setBitmap(icon, null, true, WallpaperManager.FLAG_LOCK);
} catch (IOException e) {
e.printStackTrace();
}

usage for api30+
public void onWallpaperChanged(Bitmap bitmap, boolean onHomeScreen, boolean onLockScreen) {
WallpaperManager myWallpaperManager = WallpaperManager.getInstance(getApplicationContext());
try {
if(onHomeScreen) {
myWallpaperManager.setBitmap(bitmap);// For Home screen
}
if(onLockScreen) {
myWallpaperManager.setBitmap(bitmap,null,true, WallpaperManager.FLAG_LOCK);//For Lock screen
}
} catch (IOException e) {
e.printStackTrace();
}
}

Since API level 24, you can set wallpaper to your home screen, lock screen, or both:
WallpaperManager wallpaperManager = WallpaperManager.getInstance(getApplicationContext());
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
// home screen
wallpaperManager.setBitmap(mBitmap, null, true, WallpaperManager.FLAG_SYSTEM);
// lock screen
wallpaperManager.setBitmap(mBitmap, null, true, WallpaperManager.FLAG_LOCK);
// home screen & lock screen
wallpaperManager.setBitmap(mBitmap, null, true, WallpaperManager.FLAG_LOCK | WallpaperManager.FLAG_SYSTEM);
} else {
wallpaperManager.setBitmap(mBitmap);
}
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