commonsguy/cwac-camera · GitHubCWAC-Camera is an effort to s

Taking pictures or videos using a third-party app is fairly straightforward, using ACTION_IMAGE_CAPTURE or ACTION_VIDEO_CAPTURE. However, you as the developer have little control over what happens with the image or video, other than indicating where the result gets stored. Plus, different camera apps have slightly different behavior, meaning that you are prone to getting inconsistent results.

Taking pictures or videos using the built-in Camera class directly is eminently possible, but is full of edge and corner cases, not to mention its own set of per-device idiosyncracies. As a result, a ton of code is required to successfully show a preview, take a picture, and take a video.

CWAC-Camera is an effort to standardize that "ton of code" and hide it behind a scalable API. Here, "scalable" means "simple things are simple, but complex things may be a bit complex".

This Android library project is also available as a JAR.

If you are upgrading a project using CWAC-Camera to a new edition of the library, please see the "Upgrading" section below.

Basic Usage

Step #1: Download the JAR and put it in the libs/ directory of your project (or, if you prefer, clone this GitHub repo and add it as a library project to your main project).

Step #2: Add a CameraFragment to your UI. You have two versions of CameraFragment to choose from:

com.commonsware.cwac.camera.CameraFragment for use with native API Level 11+ fragments
com.commonsware.cwac.camera.acl.CameraFragment for use with the Android Support package's backport of fragments and ActionBarSherlock, supporting API Level 9 and 10

(note: if you choose the latter, your project will also need to have the ActionBarSherlock library project)

The CameraFragment is responsible for rendering your preview, so you need to size and position it as desired.

Step #3: Call takePicture() on the CameraFragment when you want to take a picture, which will be stored in the default digital photos directory (e.g., DCIM) on external storage as Photo_yyyyMMdd_HHmmss.jpg, where yyyyMMdd_HHmmss is replaced by the current date and time.

Step #3b: Call startRecording() and stopRecording() on the CameraFragment to record a video. NOTE that this is presently only available on com.commonsware.cwac.camera.CameraFragment for use with native API Level 11+ fragments. The resulting video will be stored in the default videos directory (e.g., Movies) on external storage as Video_yyyyMMdd_HHmmss.mp4, where yyyyMMdd_HHmmss is replaced by the current date and time.

Step #4: Add android:largeHeap="true" to the element in the manifest (a requirement which will hopefully be relaxed in the future).

And that's it.

CameraFragment (and its underlying CameraView) will handle:

Showing the preview using an optimal preview frame size, and managing the aspect ratio of the on-screen preview View so that your previews do not appear stretched
Dealing with configuration changes and screen rotation, so your camera activity can work in portrait or landscape
Following the appropriate recipes for taking still pictures and videos, including choosing the largest-available image size for the resolution
Opening and closing the camera at the appropriate times, so when you are in the foreground you have exclusive camera access, but other apps will have access to the camera while your activity is not in the foreground
And more!

Simple Configuration and Usage

Of course, there are probably plenty of things that you will want to configure about the process of taking photos and videos. There are many hooks in CWAC-Camera to allow you to do just that.

Much of this configuration involves creating a custom CameraHost. CameraHost is your primary interface with the CWAC-Camera classes for configuring the behavior of the camera. CameraHost is an interface, one that you are welcome to implement in full. Most times, though, you will be better served extending SimpleCameraHost, the default implementation of CameraHost, so that you can override only those methods where you want behavior different from the default.

Given a customized CameraHost implementation, you can pass an instance of that to setHost() on your CameraFragment, to replace the default. Do this in onCreate() of a CameraFragment subclass (or, if practical, just after instantiating your fragment) to ensure that the right CameraHost is used everywhere.

Controlling the Names and Locations of Output Files

There are a series of methods that you can override on SimpleCameraHost to control where photos and videos are stored once taken. These methods will be called for each takePicture() or startRecording() call, so you can create customized results for each distinct photo or video.

Specifically:

Override getPhotoFilename() to return the base name of the file to use to store the photo
Override getPhotoDirectory() to return the name of the directory in which to store the photo
Override getPhotoPath() to return the complete File object pointing to the desired file in the desired directory (the default implementation combines the results of getPhotoDirectory() and getPhotoFilename(), so overriding getPhotoPath() replaces all of that)

There are equivalent getVideoFilename(), getVideoDirectory(), and getVideoPath() for controlling the output of the next video to be taken.

By default, if you are using SimpleCameraHost, your image will be indexed by the MediaStore. If you do not want this, override scanSavedImage() to return false in your SimpleCameraHost subclass. This is called on a per-image basis.

Controlling Which Camera is Used

If you override useFrontFacingCamera() on SimpleCameraHost to return true, the front-facing camera will be used, instead of the default rear-facing camera.

Or, override getDeviceId() (available on CameraHost), and you can provide the ID of the specific camera you want. This would involve your choosing an available camera based on your own criteria. See the JavaDocs for Android's Camera class, notably getNumberOfCameras()) and getCameraInfo()) for more.

Controlling FFC Mirror Correction

By default, the pictures taken from the front-facing camera are a mirror image of what is shown on the preview. If you wish for the front-facing camera photos to match the preview, override mirrorFFC() on your CameraHost and have it return true, and CWAC-Camera will reverse the image for you before saving it.

Handling Exceptions

There are some exceptions that are thrown by the Camera class (and kin, like MediaRecorder). Those are passed to your host's handleException() method. The default implementation displays a Toast and logs the message to LogCat as an error, but you probably will want to replace that with something else that integrates better with your UI.

Wrapping the Preview UI

From a UI standpoint, the CameraFragment solely handles the preview pane. Presumably, you will need more to your UI than this, such as buttons to allow users to take pictures or record videos. You have two major options here:

You can put that UI as a peer to the CameraFragment, such as by having action bar items, as the demo apps do.
You can subclass CameraFragment and override onCreateView(). Chain to the superclass to get the CameraFragment's own UI, then wrap that in your own container with additional widgets, and return the combined UI from your onCreateView().

Auto-Focus

You can call autoFocus() on CameraFragment or CameraView to trigger any auto-focus behavior that you have configured via setFocusMode() on Camera.Parameters. You can call cancelAutoFocus() on CameraFragment or CameraView to ensure that auto-focus mode has been canceled.

Note that auto-focus is only available in certain conditions, notably when the preview mode is enabled. You can call isAutoFocusAvailable() on CameraFragment or CameraView to determine if auto-focus is presently available for use. Calling autoFocus() when auto-focus is not available will have no effect.

CameraHost implementations will need to implement an onAutoFocus() method, coming from the Camera.AutoFocusCallback interface that CameraHost extends. SimpleCameraHost has a default implementation of onAutoFocus() that plays a device-standard sound upon completion (API Level 16+ only).

CameraHost implementations will also need autoFocusAvailable() and autoFocusUnavailable() methods, to be notified when auto-focus is available or not. This can be used to trigger whether action bar items are enabled, etc. SimpleCameraHost has no-op implementations of these callbacks.

Single-Shot Mode

By default, the result of taking a picture is to return the CameraFragment to preview mode, ready to take the next picture. If, instead, you only need the one picture, or you want to send the user to some other bit of UI first and do not want preview to start up again right away, override useSingleShotMode() in your CameraHost to return true.

You will then probably want to use your own saveImage() implementation in your CameraHost to do whatever you want instead of restarting the preview. For example, you could start another activity to do something with the image. However, bear in mind that an Intent is limited to ~1MB, and so passing an image to another activity via a Intent extra is likely to be unreliable. You will need to do something else, such as (carefully) use a static data member.

Preview mode will re-enable automatically after an onPause()/onResume() cycle of your CameraFragment, or you can call restartPreview() on your CameraFragment (or CameraView).

Advanced Configuration

In addition to the configuration hooks specified above, you can do more to tailor how photos and videos are taken.

Controlling Preview Sizes

Your CameraHost will be called with getPreviewSize(), where you need to return a valid Camera.Size indicating the desired size of the preview frames. getPreviewSize() is passed:

the display orientation, in degrees, with 0 indicating landscape, 90 indicating portrait, etc.
the available width and height for the preview
the Camera.Parameters object, from which you can determine the valid preview sizes by calling getSupportedPreviewSizes()

The CameraUtils class contains a pair of static methods with stock algorithms for choosing the preview size:

getOptimalPreviewSize() uses the algorithm found in the SDK camera sample app
getBestAspectPreviewSize() finds the preview size that most closely matches the aspect ratio of our available space

SimpleCameraHost uses getBestAspectPreviewSize() for the default implementation of getPreviewSize(). You can override getPreviewSize() and substitute in your own selection algorithm. Just make sure that the returned size is one of the ones returned by getSupportedPreviewSizes().

However, SimpleCameraHost also calls mayUseForVideo() on your subclass. If this returns true (the default), SimpleCameraHost calls getPreferredPreviewSizeForVideo() on Camera.Parameters, to get a preview size that will work for both still images and video. If you know that you will not be recording any video, you can override mayUseForVideo() to return false, and you may get a better preview size as a result.

Controlling Picture Sizes

Similarly, your CameraHost will be called with getPictureSize(), for you to return the desired Camera.Size of the still images taken by the camera. You are simply passed the Camera.Parameters, on which you can call getSupportedPictureSizes() to find out the possible picture sizes that you can choose from.

The CameraUtils class has a pair of methods for simple algorithms for choosing a picture size:

getLargestPictureSize() returns the Camera.Size that is the largest in area
getSmallestPictureSize() returns the Camera.Size that is the smallest in area

SimpleCameraHost uses getLargestPictureSize() for the default implementation of getPictureSize(). You can override getPictureSize() and substitute in your own selection algorithm. Just make sure that the returned size is one of the ones returned by getSupportedPictureSizes().

Arbitrary Preview Configuration

When setting up the camera preview, your CameraHost will be called with adjustPreviewParameters(), passing in a Camera.Parameters. Here, you can make any desired adjustments to the camera preview, except the preview size (which you should be handling in getPreviewSize()). adjustPreviewParameters() returns the revised Camera.Parameters, where the stock implementation in SimpleCameraHost just returns the passed-in parameters unmodified.

Arbitrary Photo Configuration

Shortly after you call takePicture() on your CameraFragment, your CameraHost will be called with adjustPictureParameters(), passing in a Camera.Parameters. Here, you can make any desired adjustments to the parameters related to taking photos, except the image size (which you should be handling in getPictureSize()). adjustPictureParameters() returns the revised Camera.Parameters, where the stock implementation in SimpleCameraHost just returns the passed-in parameters unmodified.

Arbitrary Video Configuration

Shortly after you call startRecording(), your CameraHost will be called with:

configureRecorderAudio()
configureRecorderProfile()
configureRecorderOutput()

in that order. Here, you can help tailor the way videos get recorded. Each of these is passed the ID of the camera being used for recording plus the MediaRecorder instance that does the actual recording.

The stock SimpleCameraHost does the following:

In configureRecorderAudio(), SimpleCameraHost calls setAudioSource(MediaRecorder.AudioSource.CAMCORDER) on the MediaRecorder
In configureRecorderProfile(), SimpleCameraHost calls setProfile(CamcorderProfile.get(cameraId, CamcorderProfile.QUALITY_HIGH)) on the MediaRecorder
In configureRecorderOutput(), SimpleCameraHost calls setOutputFile(getVideoPath().getAbsolutePath()) on the MediaRecorder (where getVideoPath() was described earlier in this document)

While these are reasonable defaults, you are welcome to override these implementations to do something else.

Overriding Photo Saving

The default SimpleCameraHost logic for saving photos uses the getPhotoPath() and related methods discussed above. Actually saving the photo is done in saveImage(byte[]), called on your CameraHost, where SimpleCameraHost has a saveImage(byte[]) implementation that writes the supplied byte[] out to the desired location.

You are welcome to override saveImage(byte[]) and do something else with the byte[], such as send it over the Internet. saveImage(byte[]) is called on a background thread, so you do not have to do your own asynchronous work.

Another use for this is to find out when the saving is complete, so that you can use the resulting image. Just override saveImage(byte[]), chain to the superclass implementation, and when that returns, the image is ready for use.

There is also a saveImage(Bitmap) callback, giving you a decoded Bitmap instead of a byte[]. To use this, there is a second version of takePicture() that you can call that takes two boolean parameters, indicating whether or not you want the saveImage(Bitmap) callback called and/or the saveImage(byte[]) callback called. The zero-argument takePicture() indicates that you only want saveImage(byte[]) called. If you pass true as the first parameter to the two-parameter takePicture() method, then your host will be called with saveImage(Bitmap). Note that if you do this, you are responsible for the Bitmap (e.g., calling recycle() on it) once it is handed to your host.

Controlling the Shutter Callback

Your CameraHost implementation can return a Camera.ShutterCallback object via getShutterCallback(), which will be used in the underlying takePicture() call on the Android Camera, giving you control to play a "shutter click" sound. SimpleCameraHost returns null from getShutterCallback(), to give you the device default behavior.

Controlling EXIF Rotation Behavior

Device cameras are generally set up to take landscape pictures. If you try to use a camera to take a picture in portrait mode, one of three things will happen:

Everything works fine, with the device capturing a portrait image
The device crashes (this scenario CWAC-Camera aims to handle)
The device captures a landscape image, but sets an EXIF header to indicate that an image viewer should rotate the image to portrait when displaying it

The problem with the last scenario is that not all image viewers will honor this EXIF header.

Your CameraHost will need to implement rotateBasedOnExif() to indicate if you want the library to rotate the image automatically. If you return true, you will get a portrait image from all devices, for all three of the above scenarios. If you return false, the last scenario will be ignored, and you may get a portrait or a landscape image.

SimpleCameraHost returns true for rotateBasedOnExif().

Choosing a DeviceProfile

CameraHost exists to provide a hook for you to determine how your app should handle taking pictures and videos. DeviceProfile, on the other hand, provides information about how the device handles taking pictures and videos. Different devices do slightly different things when working with the camera. Sometimes this is based on API level, sometimes it is based on how the device manufacturer tinkered with Android, and sometimes it is based on the underlying camera hardware. DeviceProfile provides a place for the CWAC-Camera project to isolate these differences.

CameraHost has a getDeviceProfile() method that should return an instance of the DeviceProfile to use for the device that is running the app. The implementation of getDeviceProfile() on SimpleCameraHost calls the static getInstance() method on DeviceProfile, which chooses a DeviceProfile based on internal heuristics. If you encounter problems with certain devices, you can detect those in your getDeviceProfile() method and return a DeviceProfile that addresses your needs, otherwise settling for using the library's own choice of DeviceProfile.

At present, there are four methods on DeviceProfile that you can tailor in your subclasses:

useTextureView() should return true if CameraView should use a TextureView for rendering the preview frames, or false if a SurfaceView should be used instead
encodesRotationToExif() indicates if the device puts information about the device orientation into EXIF headers of the JPEG image
rotateBasedOnExif() should return true if the library should attempt to physically change the orientation of the image if the EXIF orientation header indicates that the image should be changed, false otherwise
getMaxPictureHeight() returns the maximum image height to be selected by CameraUtils.getLargestPictureSize(), to work around devices that report invalid large Camera.Size values

Working Directly with CameraView

If you wish to eschew fragments, you are welcome to work with CameraView directly. To do this:

Add it in Java code by calling its one-parameter constructor, taking your Activity as a parameter. At the present time, CameraView does not support being placed in a layout resource.
Call setHost() on the CameraView as early as possible, to make sure that the CameraView is working with the right CameraHost implementation. Alternatively, override getHost() and return the right CameraHost there.
Forward the onResume() and onPause() lifecycle events from your activity or fragment to the CameraView.

Otherwise, CameraView should work as a regular View.

Known Limitations

These are above and beyond the bugs filed for this project:

Taking videos in portrait mode will result in the video files still being stored as landscape, but with a bit in the MPEG-4 header indicating that the output should be rotated. Unfortunately, many video players ignore this header. This is a function of how MediaRecorder works, and there is no current workaround in CWAC-Camera for this behavior.
Taking photos in portrait mode, for some devices, will have a similar effect: the photo is saved in landscape, with an EXIF field in the JPEG indicating that the results should be rotated. CWAC-Camera detects this and tries to correct it, so the image is saved in portrait. However, this may consume too much memory at present, which is why Step #4 above calls for you to add android:largeHeap="true". This will hopefully be rectified in a future version of this component.
While a picture or video is being taken, on some devices, the aspect ratio of the preview gets messed up. The aspect ratio is corrected by CWAC-Camera once the picture or video is completed, but more work is needed to try to prevent this in the first place, or at least mask it a bit better for photos.
The Samsung Galaxy Ace refuses to honor a portrait preview in an activity that itself supports portrait or landscape. If you lock your activity to only display in landscape, the Galaxy Ace will work probably.

Upgrading

If you are moving from an older to a newer edition of CWAC-Camera, here are some upgrade notes which may help.

From 0.1.x to 0.2.0 and Higher

CameraHost now extends Camera.AutoFocusCallback, requiring an implementation of onAutoFocus(). SimpleCameraHost shows a basic implementation that, on API Level 16+, plays the device-standard "hey! you're focused now!" sound.

From 0.0.x to 0.1.0 and Higher

Developers moving from v0.0.x to v0.1.x should note that you now need to pass a Context into the constructor of SimpleCameraHost. This can be any Context, as SimpleCameraHost retrieves the Application singleton from it, so you do not have to worry about memory leaks.

Tested Devices

Acer Iconia Tab A700
Amazon Kindle Fire HD
ASUS Transformer Infinity (1st generation)
Galaxy Nexus
HTC Droid Incredible 2
HTC One S
Lenovo ThinkPad Tablet
Nexus 4
Nexus 7 (1st generation, 2012)
Nexus 7 (2nd generation, 2013)
Nexus 10
Nexus One
Nexus S
Motorola RAZR i
Samsung Galaxy Note 2
Samsung Galaxy S3
Samsung Galaxy S4 (GT-I9500)
Samsung Galaxy Tab 2
SONY Ericsson Xperia Play
SONY Xperia E
Sony Xperia S LT26i
SONY Xperia Z

Dependencies

This project depends on the Android Support package and ActionBarSherlock at compile time, if you are using the Android library project. It also depends on the Android Support package and ActionBarSherlock at runtime if you are using the .acl flavor of CameraFragment.

Version

This is version v0.2.1 of this module, meaning it is rather new.

Demo

In the demo/ sub-project you will find a sample project demonstrating the use of CameraFragment for the native API Level 11 implementation of fragments. The demo-v9/ sub-project has a similar sample for the CameraFragment that works with ActionBarSherlock.

License

The code in this project is licensed under the Apache Software License 2.0, per the terms of the included LICENSE file.

Questions

If you have questions regarding the use of this code, please post a question on StackOverflow tagged with commonsware and android. Be sure to indicate what CWAC module you are having issues with, and be sure to include source code and stack traces if you are encountering crashes.

If you have encountered what is clearly a bug, or if you have a feature request, please post an issue. Be certain to include complete steps for reproducing the issue.

Do not ask for help via Twitter.

Also, if you plan on hacking on the code with an eye for contributing something back, please open an issue that we can use for discussing implementation details. Just lobbing a pull request over the fence may work, but it may not.

Release Notes

v0.3.0: improved support for auto-focus, Samsung Galaxy Camera, etc.
v0.2.1: CyanogenMod devices will now use SurfaceView regardless of API level
v0.2.0: auto-focus support, single-shot mode, Droid Incredible 2 fixes
v0.1.1: improved support for Nexus 4 and Galaxy Tab 2
v0.1.0: Nexus S crash fixed, added support for indexing images to MediaStore
v0.0.4: Nexus S EXIF issue fixed, added saveImage(Bitmap) callback
v0.0.3: shutter callback support, bug fixes
v0.0.2: bug fixes
v0.0.1: initial release