Develop Reference

Decoding bitmap from Drawable Resource Id is giving null

I want to get Bitmap from drawable resource id, I found a solution to decode it using BitmapFactory decode method, but it's giving null.
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_tick);

Please check if you are using Vector drawable or normal png/jpeg image as a drawable, it gives null value if you try to decode vector drawable.
Use this code if you are trying to decode Vector drawable
public static Bitmap getBitmapFromVectorDrawable(Context context, int drawableId) {
Drawable drawable = ContextCompat.getDrawable(context, drawableId);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
drawable = (DrawableCompat.wrap(drawable)).mutate();
}
Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
}
Also make sure if you have vector support enable in your app gradle
vectorDrawables.useSupportLibrary = true

Android how to capture shadow in screenshots

How to capture shadow or elevation of views in the layout of the activity in a screenshots.This code take a screenshot for the view but it's not showing the shadow of the viewsenter image description here
View screenView = parentMain;
screenView.buildDrawingCache();
screenView.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(screenView.getWidth() , screenView.getHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bitmap);
screenView.layout(0, 0, screenView.getLayoutParams().width, screenView.getLayoutParams().height);
screenView.draw(c);
screenView.setDrawingCacheEnabled(false);
fakeImgView.setImageBitmap(bitmap);
Even if we add the harware acceleration at activity level it does not provides any effect.
Appreciate any alternative approaches
the result

Try this.
CardView card = (CardView) findViewById(R.id.card);
Now just pass the card to captureScreenShot(). It returns the bitmap and save that bitmap saveImage().
You can pass any view Like RelativeLayout, LinearLayout etc any view can pass to captureScreenShot().
// Function which capture Screenshot
public Bitmap captureScreenShot(View view) {
/*
* Creating a Bitmap of view with ARGB_4444.
* */
Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_4444);
Canvas canvas = new Canvas(bitmap);
Drawable backgroundDrawable = view.getBackground();
if (backgroundDrawable != null) {
backgroundDrawable.draw(canvas);
} else {
canvas.drawColor(Color.parseColor("#80000000"));
}
view.draw(canvas);
return bitmap;
}
// Function which Save image.
private void saveImage(Bitmap bitmap) {
File file = // Your Storage directory name + your filename
if (file == null) {
return;
}
try {
FileOutputStream fos = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
Finally call this function like this.
saveImage(captureScreenShot(card));
Now set Your Image like this.
File file = new File(“yourImageFilePath”);
if(file.exists())
{
yourImageView.setImageURI(Uri.fromFile(file));
}
Note : If setImageURI() not working then you can use below code.
File file = new File(“yourImageFilePath”);
if(file.exists())
{
Bitmap bitmap = BitmapFactory.decodeFile(file.toString());
yourImageView.setImageBitmap(bitmap);
}

Updating MainActivity's TextView in ImageReader's OnImageAvailable

My task is to get preview frames from camera, process them and update a TextView in my layout.I'm referring google's camera2 sample code and have managed to get frames using OnImageAvailableListener's OnImageAvailable() method, but I can't update my TextView's content in OnImageAvailable() definition(App crashes). I'm fairly new to Android programming and java. Any way to update my TextView after getting each frame.
Definition of OnImageAvailable(part of a fragment, not the CameraActivity, like google's sample):
public final ImageReader.OnImageAvailableListener mOnImageAvailableListener
= new ImageReader.OnImageAvailableListener() {
#Override
public void onImageAvailable(ImageReader reader) {
Image image = null;
try {
image = reader.acquireLatestImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] imageBytes = new byte[buffer.remaining()];
buffer.get(imageBytes);
final Bitmap bitmap = BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
textView.append("a"); // crashes here
} finally {
if (image != null) {
image.close();
}
}
}
};
Crash log from Android Monitor:
03-19 13:14:12.384 13895-14107/com.example.android.camera2basic E/AndroidRuntime: FATAL EXCEPTION: CameraBackground
Process: com.example.android.camera2basic, PID: 13895
android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6462)
at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:932)
at android.view.ViewGroup.invalidateChild(ViewGroup.java:4692)
at android.view.View.invalidateInternal(View.java:11806)
at android.view.View.invalidate(View.java:11770)
at android.view.View.invalidate(View.java:11754)
at android.widget.TextView.checkForRelayout(TextView.java:6867)
at android.widget.TextView.setText(TextView.java:4063)
at android.widget.TextView.setText(TextView.java:3921)
at android.widget.TextView.append(TextView.java:3627)
at android.widget.TextView.append(TextView.java:3617)
at com.example.android.camera2basic.Camera2BasicFragment$6.onImageAvailable(Camera2BasicFragment.java:760)
at android.media.ImageReader$ListenerHandler.handleMessage(ImageReader.java:548)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.os.HandlerThread.run(HandlerThread.java:61)

You need to put it in a runnable/thread. I'm not really versed with it but maybe this might help, but if it doesn't, I'm more than sure it's pointing in the right direction to a solution
public final ImageReader.OnImageAvailableListener mOnImageAvailableListener
= new ImageReader.OnImageAvailableListener() {
#Override
public void onImageAvailable(final ImageReader reader) {
Image image = null;
try {
image = reader.acquireLatestImage();
ByteBuffer buffer = image.getPlanes()[0].getBuffer();
byte[] imageBytes = new byte[buffer.remaining()];
buffer.get(imageBytes);
final Bitmap bitmap = BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
YourClassNameHere.this.runOnUIThread(new Runnable() {
#Override
public void run() {
textView.append("a"); // crashes here
});
} finally {
if (image != null) {
image.close();
}
}
}
}
};

java.lang.NullPointerException in android.util.LruCache.put ( Android )

I'm getting this crash exception in my google Crashes & ANRs section for my app java.lang.NullPointerException in android.util.LruCache.put
I have no idea what's wrong I do need some help please, why I do get this null pointer exception and how to fix it.
Crashes & ANRs:
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
Caused by: java.lang.NullPointerException: key == null || value == null
at android.util.LruCache.put(LruCache.java:167)
at
com.b3du.im.GridAdapter.addBitmapToMemoryCache(GridAdapter.java:77)
at com.b3du.im.GridAdapter$BitmapWorkerTaskVideo.doInBackground(GridAdapter.java:218)
at com.b3du.im.GridAdapter$BitmapWorkerTaskVideo.doInBackground(GridAdapter.java:205)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
... 4 more
Code:
public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null) {
mMemoryCache.put(key, bitmap);
}
}
public Bitmap getBitmapFromMemCache(String key) {
return mMemoryCache.get(key);
}
class BitmapWorkerTaskVideo extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
public BitmapWorkerTaskVideo(ImageView imageView) {
// Use a WeakReference to ensure the ImageView can be garbage collected
imageViewReference = new WeakReference<ImageView>(imageView);
}
// Decode image in background.
#Override
protected Bitmap doInBackground(String... params) {
final Bitmap bitmap = decodeSnapshotFromFileVideo(params[0], 100, 100);
addBitmapToMemoryCache(String.valueOf(params[0]), bitmap);
return bitmap;
}
// Once complete, see if ImageView is still around and set bitmap.
#Override
protected void onPostExecute(Bitmap bitmap) {
if (imageViewReference != null && bitmap != null) {
final ImageView imageView = imageViewReference.get();
if (imageView != null) {
imageView.setImageBitmap(bitmap);
}
}
}
public Bitmap decodeSnapshotFromFileVideo (String filepath, int reqWidth, int reqHeight) {
//Create a file, using the filepath
File file = new File (filepath);
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
ThumbnailUtils.createVideoThumbnail(file.getAbsolutePath(), MediaStore.Video.Thumbnails.MICRO_KIND);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
return ThumbnailUtils.createVideoThumbnail(file.getAbsolutePath(), MediaStore.Video.Thumbnails.MICRO_KIND);
}

public static Bitmap createVideoThumbnail (String filePath, int kind)
Create a video thumbnail for a video. May return null if the video is corrupt or the format is not supported.
So, Might be bitmap value is null. to avoid this Write your code like this:
if(bitmap != null)
{
addBitmapToMemoryCache(String.valueOf(params[0]), bitmap);
}

It's because ThumbnailUtils.createVideoThumbnail() can return null
So you will need to add check NPE for the bitmap in addBitmapToMemoryCache() method

Set content of imageView as wallpaper (Picasso)

I'm using the picasso library for my app and it works very well so far. I have two activities, one which displays all the images and one that displays one image when I clicked on it in the first activity. The image is loaded into an imageView.
Now I want to set the content of this imageView as my homescreen wallpaper. So far I have this:
if (id == R.id.set_wall) {
Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.id.image);
WallpaperManager myWallpaperManager = WallpaperManager
.getInstance(getApplicationContext());
try {
myWallpaperManager.setBitmap(mBitmap);
Toast.makeText(DetailActivity.this, "Wallpaper set",
Toast.LENGTH_SHORT).show();
} catch (IOException e) {
Toast.makeText(DetailActivity.this,
"Error setting wallpaper", Toast.LENGTH_SHORT)
.show();
}
return true;
}
But this gives me this error:
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
Does anyone have an idea how I can set the content of this imageView as my wallpaper?
Thank you a lot!!

replace Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.id.image);
by Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.image);
if you do not have a Drawable then ,
code to get bitmap from imageview
Bitmap bitmap = ((BitmapDrawable)image.getDrawable()).getBitmap();