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How to programatically take a screenshot on Android?
How to capture the android device screen content and make an image file using the snapshot data? Which API should I use or where could I find related resources?
BTW:
not camera snapshot, but device screen
Use the following code:
Bitmap bitmap;
View v1 = MyView.getRootView();
v1.setDrawingCacheEnabled(true);
bitmap = Bitmap.createBitmap(v1.getDrawingCache());
v1.setDrawingCacheEnabled(false);
Here MyView is the View through which we need include in the screen. You can also get DrawingCache from of any View this way (without getRootView()).
There is also another way.. If we having ScrollView as root view then its better to use following code,
LayoutInflater inflater = (LayoutInflater) this.getSystemService(LAYOUT_INFLATER_SERVICE);
FrameLayout root = (FrameLayout) inflater.inflate(R.layout.activity_main, null); // activity_main is UI(xml) file we used in our Activity class. FrameLayout is root view of my UI(xml) file.
root.setDrawingCacheEnabled(true);
Bitmap bitmap = getBitmapFromView(this.getWindow().findViewById(R.id.frameLayout)); // here give id of our root layout (here its my FrameLayout's id)
root.setDrawingCacheEnabled(false);
Here is the getBitmapFromView() method
public static Bitmap getBitmapFromView(View view) {
//Define a bitmap with the same size as the view
Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),Bitmap.Config.ARGB_8888);
//Bind a canvas to it
Canvas canvas = new Canvas(returnedBitmap);
//Get the view's background
Drawable bgDrawable =view.getBackground();
if (bgDrawable!=null)
//has background drawable, then draw it on the canvas
bgDrawable.draw(canvas);
else
//does not have background drawable, then draw white background on the canvas
canvas.drawColor(Color.WHITE);
// draw the view on the canvas
view.draw(canvas);
//return the bitmap
return returnedBitmap;
}
It will display entire screen including content hidden in your ScrollView
UPDATED AS ON 20-04-2016
There is another better way to take screenshot.Here I have taken screenshot of WebView.
WebView w = new WebView(this);
w.setWebViewClient(new WebViewClient()
{
public void onPageFinished(final WebView webView, String url) {
new Handler().postDelayed(new Runnable(){
#Override
public void run() {
webView.measure(View.MeasureSpec.makeMeasureSpec(
View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
webView.layout(0, 0, webView.getMeasuredWidth(),
webView.getMeasuredHeight());
webView.setDrawingCacheEnabled(true);
webView.buildDrawingCache();
Bitmap bitmap = Bitmap.createBitmap(webView.getMeasuredWidth(),
webView.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
int height = bitmap.getHeight();
canvas.drawBitmap(bitmap, 0, height, paint);
webView.draw(canvas);
if (bitmap != null) {
try {
String filePath = Environment.getExternalStorageDirectory()
.toString();
OutputStream out = null;
File file = new File(filePath, "/webviewScreenShot.png");
out = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.PNG, 50, out);
out.flush();
out.close();
bitmap.recycle();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}, 1000);
}
});
Hope this helps..!
AFAIK, All of the methods currently to capture a screenshot of android use the /dev/graphics/fb0 framebuffer. This includes ddms. It does require root to read from this stream. ddms uses adbd to request the information, so root is not required as adb has the permissions needed to request the data from /dev/graphics/fb0.
The framebuffer contains 2+ "frames" of RGB565 images. If you are able to read the data, you would have to know the screen resolution to know how many bytes are needed to get the image. each pixel is 2 bytes, so if the screen res was 480x800, you would have to read 768,000 bytes for the image, since a 480x800 RGB565 image has 384,000 pixels.
For newer Android platforms, one can execute a system utility screencap in /system/bin to get the screenshot without root permission.
You can try /system/bin/screencap -h to see how to use it under adb or any shell.
By the way, I think this method is only good for single snapshot.
If we want to capture multiple frames for screen play, it will be too slow.
I don't know if there exists any other approach for a faster screen capture.
[Based on Android source code:]
At the C++ side, the SurfaceFlinger implements the captureScreen API. This is exposed over the binder IPC interface, returning each time a new ashmem area that contains the raw pixels from the screen. The actual screenshot is taken through OpenGL.
For the system C++ clients, the interface is exposed through the ScreenshotClient class, defined in <surfaceflinger_client/SurfaceComposerClient.h> for Android < 4.1; for Android > 4.1 use <gui/SurfaceComposerClient.h>
Before JB, to take a screenshot in a C++ program, this was enough:
ScreenshotClient ssc;
ssc.update();
With JB and multiple displays, it becomes slightly more complicated:
ssc.update(
android::SurfaceComposerClient::getBuiltInDisplay(
android::ISurfaceComposer::eDisplayIdMain));
Then you can access it:
do_something_with_raw_bits(ssc.getPixels(), ssc.getSize(), ...);
Using the Android source code, you can compile your own shared library to access that API, and then expose it through JNI to Java. To create a screen shot form your app, the app has to have the READ_FRAME_BUFFER permission.
But even then, apparently you can create screen shots only from system applications, i.e. ones that are signed with the same key as the system. (This part I still don't quite understand, since I'm not familiar enough with the Android Permissions system.)
Here is a piece of code, for JB 4.1 / 4.2:
#include <utils/RefBase.h>
#include <binder/IBinder.h>
#include <binder/MemoryHeapBase.h>
#include <gui/ISurfaceComposer.h>
#include <gui/SurfaceComposerClient.h>
static void do_save(const char *filename, const void *buf, size_t size) {
int out = open(filename, O_RDWR|O_CREAT, 0666);
int len = write(out, buf, size);
printf("Wrote %d bytes to out.\n", len);
close(out);
}
int main(int ac, char **av) {
android::ScreenshotClient ssc;
const void *pixels;
size_t size;
int buffer_index;
if(ssc.update(
android::SurfaceComposerClient::getBuiltInDisplay(
android::ISurfaceComposer::eDisplayIdMain)) != NO_ERROR ){
printf("Captured: w=%d, h=%d, format=%d\n");
ssc.getWidth(), ssc.getHeight(), ssc.getFormat());
size = ssc.getSize();
do_save(av[1], pixels, size);
}
else
printf(" screen shot client Captured Failed");
return 0;
}
You can try the following library: Android Screenshot Library (ASL) enables to programmatically capture screenshots from Android devices without requirement of having root access privileges. Instead, ASL utilizes a native service running in the background, started via the Android Debug Bridge (ADB) once per device boot.
According to this link, it is possible to use ddms in the tools directory of the android sdk to take screen captures.
To do this within an application (and not during development), there are also applications to do so. But as #zed_0xff points out it certainly requires root.
Framebuffer seems the way to go, it will not always contain 2+ frames like mentioned by Ryan Conrad. In my case it contained only one. I guess it depends on the frame/display size.
I tried to read the framebuffer continuously but it seems to return for a fixed amount of bytes read. In my case that is (3 410 432) bytes, which is enough to store a display frame of 854*480 RGBA (3 279 360 bytes). Yes, the frame in binary outputed from fb0 is RGBA in my device. This will most likely depend from device to device. This will be important for you to decode it =)
In my device /dev/graphics/fb0 permissions are so that only root and users from group graphics can read the fb0. graphics is a restricted group so you will probably only access fb0 with a rooted phone using su command.
Android apps have the user id (uid) app_## and group id (guid) app_## .
adb shell has uid shell and guid shell, which has much more permissions than an app.
You can actually check those permissions at /system/permissions/platform.xml
This means you will be able to read fb0 in the adb shell without root but you will not read it within the app without root.
Also, giving READ_FRAME_BUFFER and/or ACCESS_SURFACE_FLINGER permissions on AndroidManifest.xml will do nothing for a regular app because these will only work for 'signature' apps.
if you want to do screen capture from Java code in Android app AFAIK you must have Root provileges.
I'm trying to make a video out of viewshots in an app.
I have succeeeded to get the images as Bitmaps using this code.
public Bitmap getScreenShot() {
View screenView = findViewById(R.id.button);
screenView.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(screenView.getDrawingCache());
screenView.setDrawingCacheEnabled(false);
return bitmap;
}
I have encode images using SequenceEncoder like this :
for(Bitmap bitmap : bitmaps)
sequenceEncoder.encodeImage(bitmap);
I have got it working and got the file but it takes a lot of time.
I have also tried to use MediaMuxer(I used EncodeDecode) but failed to even get a video, I have tried to make a GIF(using AnimatedGifEncoder) but a lot of time too. I want a way to make this video in a very short time.
I am using OpenCV 3.0 in Java, I want to use BackgroundSubtractor to get foreground objects and also I want to get the background image, but when I call getBackgroundImage() method of BackgroundSubtractor return me an empty image. The code is bellow:
Mat backgroundImage = new Mat();
mog2.getBackgroundImage(backgroundImage);
According to the OpenCV Documentation this method can return the background image and put the data to the given Mat:
Computes a background image.
C++: void BackgroundSubtractor::getBackgroundImage(OutputArray backgroundImage) const
Parameters:
backgroundImage – The output background image.
What will be the problem? If anyone knows about this, please let me know.
Thanks in advance!
What i'm trying to do:
Pull an image from sd-card on phone using Java Plugin.
Unity passes a texture ID to plugin.
Plugin uses opengl to assign the image to the texture in Unity through the ID.
Will (eventually) be used to play a video clip from the phone in Unity, for now, it's just trying to change a texture outside of unity.
My issue:
When i call the method in the plugin, passing texture.GetNativeTextureID() into it, the texture does not change. I'm currently only using a simple black 50x50 texture for testing, and the original texture is a flat white.
I'm worried that i've missed something significant, as this is my first time working with Gl calls in java. Much of the answers to similar problems involve using native C++ instead of Java, but I can't find a concrete answer saying that C++ must be used. I'd like to do my best to avoid writing another set of plugins and plugin handlers for C++, but if it's the most efficient/only way to get this working, i'll do it as i'm not unfamiliar with OpenGL and C++
Code:
The plugin method is called from OnPreRender() in a script attached to the main camera:
if (grabTex) {
int texPtr = m_VideoTex.GetNativeTextureID();
Debug.Log( "texPtr = " + texPtr );
m_JVInterface.SetTex( texPtr );
}
m_VideoTex is a basic Texture2D( 50, 50 ) with all pixels set to white, attached to the diffuse shader on the quad in the scene.
The Java plugin code is as follows:
public void SetTexture(Context cont, int _texPointer) {
if (_texPointer != 0) {
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inScaled = false;
options.inJustDecodeBounds = false;
final Bitmap bitmap = BitmapFactory.decodeFile("/storage/emulated/0/Pictures/black.jpg", options);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, _texPointer);
GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
Log.i("VideoHandler", "Recieved ID: " + _texPointer);
bitmap.recycle();
}
}
This is most likely a problem with the OpenGL Context. The easiest way would be to send the texture as raw bytes to Unity and then upload as texture inside Unity.
Is there a way to process an image / drawable in Android (Java) to make the last X pixels of the image stretch or repeat to the bottom of the screen. I would like to know if this is possible to achieve and if there is a name for this effect or existing algorithm. Thank you in advance. Just please note that I am aware of 9patch images and it is not the way I want to go with, I explicitly need to apply this in code. Thank you in advance, bellow is an image
The best option to achieve that is using a Draw 9-patch image
Tutorials :
Android 9 Patch Image Tutorial
Draw9patch Tutorial [HD]
Possible algorithm:
1) get Bitmap object of your image
2) read image pixels(bitmap.getPixels(...) method) into an int[] array
3) create a blank bitmap of desired height
4) use setPixels() method to copy initial bitmap data to a new one
5) use same method to copy last line to new bitmap as many times as you want(use offset parameter wisely)
This sounds too complicated for such a small task, but you asked for a way of acheiving it programmatically, so here you go
EDIT Easier way for your situation:
Make use of Shader.TileMode.CLAMP
1) Create BitmapDrawable from your bitmap or from resources
2) Use setTileModeY(TilMode.CLAMP);
You can take a strip from the image and use repeat like this
<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
android:src="#drawable/your_pattern"
android:tileMode="repeat" />
EDIT : If you wanted programmatically
1- crop from the image using this code from cut the portion of bitmap :
private Bitmap cropBitmap1()
{
Bitmap bmp2 = BitmapFactory.decodeResource(this.getResources(), R.drawable.image1);
Bitmap bmOverlay = Bitmap.createBitmap(bmp2.getWidth(), 1, Bitmap.Config.ARGB_8888);
Paint p = new Paint();
p.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
Canvas c = new Canvas(bmOverlay);
c.drawBitmap(bmp2, 0, 0, null);
c.drawRect(30, 30, 100, 100, p);
return bmOverlay;
}
2- The returned bitmap , convert it to bitmapdrawable:
BitmapDrawable navigationBackground =new BitmapDrawable(getResources(),bitmap);
navigationBackground.setTileModeX(Shader.TileMode.REPEAT);