I have to crop an image. I'm using code similar to the one here. Which starts an activity which responds to this action:
"com.android.camera.action.CROP"
It works well on all devices I tested - it does find always 1 Activity and starts it. Works fine.
But can I rely on it? Or will be devices without any crop possibility (In that case I would have to implement the crop functionality in my App)?
Edit: Forgot to mention: Crop dynamically - the user will select the area (using a rectangle with fixed dimensions).
But can I rely on it?
No.
Or will be devices without any crop possibility
Yes. This has come up already. This is an undocumented, unsupported feature of one camera application that may or may not be present on the device, could be no longer exported in some future version of Android, etc.
In that case I would have to implement the crop functionality in my app
That is certainly what I would recommend. Note that there is a port of the crop activity from the Gallery app floating around GitHub somewhere that you could consider using, if you want the same basic functionality with your own private implementation.
Related
I'm using a chooser to allow the user to pick a photo from his gallery or take a new one using his camera (I copied the code from this answer).
Picking an image from the gallery works perfect. The problem is that when I capture an image with the camera It's not returning to the app and just stays in the confirmation screen...
I actually don't even need this screen to be displayed in the first place...
Can I somehow disable it or (if not) just make the Done button work?
Thanks in advance!
Can I somehow disable it
No.
just make the Done button work?
Contact the developers of your camera app, and point out the bug. Perhaps someday they will fix it.
You are using ACTION_IMAGE_CAPTURE. This launches a third-party camera app, to take a picture. There thousands of Android device models. These ship with hundreds of different pre-installed camera apps, and there are many more available for download from the Play Store and elsewhere. Any could be the one that handles a given ACTION_IMAGE_CAPTURE request, and any of them can have bugs.
I would like to use the mobile camera and develop a smart magnifier that can zoom and freeze-frame what we are viewing, so we don't have to keep holding the device steady while we read. Also should be able to change colors as given in the image in the link below.
https://lh3.ggpht.com/XhSCrMXS7RCJH7AYlpn3xL5Z-6R7bqFL4hG5R3Q5xCLNAO0flY3Fka_xRKb68a2etmhL=h900-rw
Since i'm new to android i have no idea on how to start, do you have any idea?
Thanks in advance for your help :)
I've done something similar and published it here. I have to warn you though, this is not a task to start Android development with. Not because of development skills, the showstopper here is a need for massive amount of devices to test it on.
Basically, two reasons:
Camera API is quite complicated and the different HW devices behave differently. Forget about using emulator, you would need a bunch of real HW devices.
There is a new API, Camera2 for platform 21 and higher, and the old Camera API is deprecated (kind of 'in limbo' state).
I have posted some custom Camera code on GitHub here, to show some of the hurdles involved.
So the easiest way out in your situation would be to use camera intent approach, and when you get your picture back (it is a jpeg file) just decompress it and zoom-in to the center of the resulting bitmap.
Good Luck
i'm developing an app and need to make Activity that take snapshot from current content of device screen.
note: i dont want take picture from my activity content or some view, i want take a picture from all of device screen content. ( like home screen or every applications that are on foreground). i googled many times and search so much.
there is an example code:
View screen = (View)findViewById(R.id.screen);
screen.setDrawingCacheEnabled(true);
bmScreen = screen.getDrawingCache();
showBitmap(bmScreen); // function that show my bitmap image
with this code can capture my activity's view, but i dont want capture onlye my activity. i want make a thread that capture device screen with all of its contents.
can everybody help me please?
You can't do this, mostly for security reasons. If this were possible, some rogue app could silently capture and send somewhere screenshots of everything you are doing on your device.
Why this is not available to non-system apps:
Android let's SDK applications do certain things, and explicitly forbids others. An app is not supposed to read another app's data and similarly an app cannot capture another app's screen. Google has explicitly said that third party apps are not supposed to take screencaptures of other apps. The lack of screen capture API's is a deliberate decision, not an omission. ICS offers screenshot functionality, but it is implemented by the system, and requires a hardware trigger in order to make sure it cannot be started or accessed by third party apps.
While there are ways to do this, they either require root (to read the graphics buffer directly, which is device-dependent), or are not guaranteed to work on all devices/versions.
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.
so, the way I read the documentation, using EXTRA_OUTPUT tells the camera to save the file in a specific location. That's great, but it also says to get a full size image. That's not so great.
How can I get just a small image but still specify the filename?
After trying to work with the built-in Camera activity for some time now I can advise you not to expect anything good from it because:
built-in activity differs from version to version. For example in 2.2 emulator it even crashes when you try to take a (dummy) picture.
Camera activity on real devices like Samsung Galaxy S is different, i.e. it not just looks different, it has different code and set of bugs.
Original built-in Camera activity has CROP feature, but it is not part of the public API and thus it is not good idea to use it.
So far I fount that to be safe when working with camera I need to:
- create my custom camera activity that misses the fancy stuff like filters, etc but is more configurable (I don't have it yet). I've tried to find third party Camera App but every one of them seems to be targeted at normal users not developers, i.e. has many "cool" features but it is slow / bloated / buggy / has bad UI.
- create thumbnail images by myself outside of the Camera activity (for more control).
I really hope that I am missing something here and someone will correct me in the comments with appropriate solution...
I ended up just dealing with the large images by always scaling on the read. It would have been nice not to have to do that as I read in more than one place, but ...oh well...
problem solved, although far from elegant.