I am working on a camera implementation similar to what Snapchat offers.
I have created a subclass of SimpleCameraHost to customize the directories and file paths and to handle saveImage(I am cropping the image into a square before I save it to disk). I have also subclassed CameraFragment as you(Mark) have in the demo.
I need to take three pictures(Take pic...user okays it...Move onto second pic..repeat...) before I continue with the flow of the app. I am using the single shot mode. In the Oncreate() of the DemoFragment
SimpleCameraHost.Builder builder =
new SimpleCameraHost.Builder(new MyCameraHost(getActivity(), useFFC));
setHost(builder.useSingleShotMode(true).build());
Question : I need to know how to prevent the cameraview from restarting
the camera every time I pause the app while I'm on the 'okay the pic page'
and resume.Also if I leave the app idle on this page for a while, it seems to freeze and my camera cannot be started again(from any camera app including the default...I have to restart the device). I reckon this happens because I have not released the camera. Could you please direct me as to how I should handle pausing and resuming the app.
I need to know how to prevent the cameraview from restarting the camera every time I pause the app while I'm on the 'okay the pic page' and resume
In the demo app, if I switch to single-shot mode, take a landscape picture using the rear-facing camera, press HOME from the photo-preview screen, return to the app from the recent-tasks list, and press BACK, everything behaves fine, at least on the Nexus 4 that I just tried it on.
Hence, I would suggest that you compare your app to the demo app and see where things differ that might cause this behavior.
If you feel that there is a bug in the library, feel free to file an issue, but you would need to give me a complete set of materials to be able to reproduce the problem. That would include details of the device (e.g., Build.PRODUCT), the code to reproduce it (if it is not one of the demo apps), and the steps I should manually follow to reproduce it.
Also if I leave the app idle on this page for a while, it seems to freeze and my camera cannot be started again(from any camera app including the default...I have to restart the device)
Once again, I cannot reproduce this behavior. Immediately following the steps that I outlined above, I took another picture in single-shot mode, and left the app on the photo-preview screen while I composed the first part of this answer. I just pressed BACK, and everything is normal. So, again:
Compare your app to the demo app, to see if you can determine what you may be doing that might cause this effect
File an issue if you think that it is a bug in the library, but only do so if you can give me steps to reproduce the bug
Related
I'm running into an issue and I would appreciate some guidance. I'm writing a small Android program in Android Studio that uses MediaProjection to grab a screenshot of the whole screen and then I want to pass that screenshot as a Bitmap to my System Overlay (based on the chatheads example). When the MediaProjection runs and the Imagereader creates the bitmaps, I'm passing the bitmap into a class global variable so I can pass it into my System Overlay service and display it. The problem I'm running into is if I "tab out" to a different app, my methods stop working from the MainActivity. When my app is in focus, everything works well, when a different app is focused, the system overlay contracts and expands like it should, but the screenshots are not being taken anymore. My understand is its because my app becomes "asleep" since it's not in focus. Could anyone recommend a solution? Can I momentarily awake my mainActivity so it can take a screenshot? Can I keep my activity from falling asleep on app switch? Can I bring focus to my app, take the screenshot and then switch focus to the previous app? Any other ways?
My code can be found here: https://github.com/asheron21/FacebookLikeChathead
MainActivity:https://github.com/asheron21/FacebookLikeChathead/blob/master/app/src/main/java/com/example/chatheads/MainActivity.java
Service: https://github.com/asheron21/FacebookLikeChathead/blob/master/app/src/main/java/com/example/chatheads/ChatHeadService.java
Global Variables:https://github.com/asheron21/FacebookLikeChathead/blob/master/app/src/main/java/com/example/chatheads/Globals.java
Thanks!
So, I've come to find that the method of starting a camera intent provided by:
http://developer.android.com/training/camera/photobasics.html
Will eventually fail if you take a photo, and then hit cancel multiple times. I've tried it on other apps than the one I'm building and sure enough, the application also crashes after a few photos taken and cancelled. I assume this is because each photo remains in memory until returning to another activity. Combine that with the fact that hitting the cancel button does not produce an activity result in which to handle the previously taken picture, it seems like a limitation of the camera application itself.
My question is: Is there a way of getting around this while still using the built in camera application via intent? Is there a method I can call to keep it from caching the canceled images into memory?
it seems like a limitation of the camera application itself
Please bear in mind that there are hundreds of pre-installed camera apps (across thousands of device models and well over a billion active Android users), and countless more such apps on the Play Store and elsewhere, that might respond to ACTION_CAPTURE_IMAGE. While many have bugs, the bugs vary, and so the behavior that you are seeing is tied to that specific camera app that you happen to be invoking.
I assume this is because each photo remains in memory until returning to another activity
I certainly would not assume this, but if the other app is what is crashing, there is little that you or I can do about it.
Is there a way of getting around this while still using the built in camera application via intent?
You are not in position to fix all the bugs across all the camera apps across all the devices in use.
Is there a method I can call to keep it from caching the canceled images into memory?
There is nothing in the Android SDK for you to tell another app that it has a bug and should stop breaking.
According to Eric Ahn (Android - How to stop camera intent from saving on the phone) the only way around this is to create your own camera activity and handle the callbacks yourself via the camera's API. I'll probably look into it some more later, but I suspect Eric is right.
I'm working for few weeks with Vuforia,unity and Android in one package and i a bit stuck on one problem. I manage to almost finish all parts of my application besides one.
Because i run some videos, I had to implement another activities besides main camera one, to show them there. I manage to start video, and everything is working like charm up to point when i'm getting back to main camera activity, problem is - camera is black and object is not visibile. I tried to resume or restart whole window again using resume methods and getting focus request on unityPlayer no luck though.
One thing which is even more confusing for me is, clicking app stac in android (icon which is showing all runing apps), and getting back from there is making camera work again, same thing with clicking home button.
Any ideas how i can make camera work after activity is resumed?
Marek
edit: I notice that turning of screen works too.
I want to write an activity that:
Shows the camera preview (viewfinder), and has a "capture" button.
When the "capture" button is pressed, takes a picture and returns it to the calling activity (setResult() & finish()).
Are there any complete examples out there that works on every device? A link to a simple open source application that takes pictures would be the ideal answer.
My research so far:
This is a common scenario, and there are many questions and tutorials on this.
There are two main approaches:
Use the android.provider.MediaStore.ACTION_IMAGE_CAPTURE event. See this question
Use the Camera API directly. See this example or this question (with lots of references).
Approach 1 would have been perfect, but the issue is that the intent is implemented differently on each device. On some devices it works well. However, on some devices you can take a picture but it is never returned to your app. On some devices nothing happens when you launch the intent. Typically it also saves the picture to the SD card, and requires the SD card to be present. The user interaction is also different on every device.
With approach 2 the issues is stability. I tried some examples, but I've managed to stop the camera from working (until a restart) on some devices and completely freeze another device. On another device the capture worked, but the preview stayed black.
I would have used ZXing as an example application (I work with it a lot), but it only uses the preview (viewfinder), and doesn't take any pictures. I also found that on some devices, ZXing did not automatically adjust the white balance when the lighting conditions changed, while the native camera app did it properly (not sure if this can be fixed).
Update:
For a while I used the camera API directly. This gives more control (custom UI, etc), but I would not recommend it to anyone. I would work on 90% of devices, but every now and again a new device would be released, with a different problem.
Some of the problems I've encountered:
Handling autofocus
Handling flash
Supporting devices with a front camera, back camera or both
Each device has a different combination of screen resolution, preview resolutions (doesn't always match the screen resolution) and picture resolutions.
So in general, I'd not recommend going this route at all, unless there is no other way. After two years I dumped by custom code and switched back to the Intent-based approach. Since then I've had much less trouble. The issues I've had with the Intent-based approach in the past was probably just my own incompetence.
If you really need to go this route, I've heard it's much easier if you only support devices with Android 4.0+.
With approach 2 the issues is stability. I tried some examples, but I've managed to stop the camera from working (until a restart) on some devices and completely freeze another device. On another device the capture worked, but the preview stayed black.
Either there is a bug in the examples or there is a compatibility issue with the devices.
The example that CommonsWare gave works well. The example works when using it as-is, but here are the issues I ran into when modifying it for my use case:
Never take a second picture before the first picture has completed, in other words PictureCallback.onPictureTaken() has been called. The CommonsWare example uses the inPreview flag for this purpose.
Make sure that your SurfaceView is full-screen. If you want a smaller preview you might need to change the preview size selection logic, otherwise the preview might not fit into the SurfaceView on some devices. Some devices only support a full-screen preview size, so keeping it full-screen is the simplest solution.
To add more components to the preview screen, FrameLayout works well in my experience. I started by using a LinearLayout to add text above the preview, but that broke rule #2. When using a FrameLayout to add components on top of the preview, you don't have any issues with the preview resolution.
I also posted a minor issue relating to Camera.open() on GitHub.
"the recommended way to access the camera is to open Camera on a separate thread". Otherwise, Camera.open() can take a while and might bog down the UI thread.
"Callbacks will be invoked on the event thread open(int) was called from". That's why to achieve best performance with camera preview callbacks (e.g. to encode them in a low-latency video for live communication), I recommend to open camera in a new HandlerThread, as shown here.
I have a tabHost with three activities, one of them is meant for taking pictures and uses the android camera. When I click on this tab for the first time, a blank screen appears for 1-2 seconds before the tabs reappear and the camera preview starts. Is there a way to reduce the delay or at least let the tabs stay while the camera is opened. I tried initialising the camera in a separate thread, but it gave me a runtime exception.
As I understand, you are starting the Camera intent from your application, or are you just displaying a preview of the Camera feed right on your app? Providing code with your question will help you get better answers.
Are you having this problem on the emulator? If so, it's normal behavior and you shouldn't be worried. If this is on an actual device, I don't think you can really do anything about it. Try loading the Camera application by itself and compare times with your application, it shouldn't differ by much.
Ryan