Develop Reference

Setting a bitmap using RemoteView not working

Im writing a widget and I need to download and set a bitmap on the layout. Everything I've tried doesn't seem to work.
I've created a test bitmap now to set on the view, [update] this works.
Bitmap.Config config = Bitmap.Config.ARGB_8888;
Bitmap bitmap = Bitmap.createBitmap(imageActiveWidth, imageHeight, config);
Canvas canvas = new Canvas(bitmap); // Load the Bitmap to the Canvas
Paint paint = new Paint();
paint.setColor(0xFFFFCCFF);
canvas.drawRect(0, 0, imageActiveWidth, imageHeight, paint);
views.setImageViewBitmap(resId, bitmap);
using a resource file does work:
Bitmap placeholderBitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.placeholder_medium);
views.setImageViewBitmap(imageSlotId, placeholderBitmap);
However using a downloaded bitmap does not seem work.
(after async task has downloaded bitmap, I have a method setBitmap which is one line:
views.setImageViewBitmap(resId, proxy);
Result - screen is just white, no bitmap
I'm really stumped on how to get this to work, because I need to be able to download bitmaps and set them.

Found a solution. I think its related to this bug:
http://code.google.com/p/android/issues/detail?id=8489
Solved by changing by setBitmap method to the following:
private void setBitmap(RemoteViews views, int resId, Bitmap bitmap){
Bitmap proxy = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(proxy);
c.drawBitmap(bitmap, new Matrix(), null);
views.setImageViewBitmap(resId, proxy);
}
And I needed to call:
AppWidgetManager.getInstance(context).updateAppWidget(appWidgetId, views);
AFTER the bitmaps had been set.
For some reason this wasn't working when I came back to it. My view was an AdapterViewFlipper, so i used the above method with a call to widgetManager.notifyAppWidgetViewDataChanged(appWidgetId, R.id.content); which caused the bitmaps to render.

OutOfMemoryException when using large images

I tried to post an image on Facebook wall from my android application.For this I created a bitmap from layout.Here is my code
System.gc();
Bitmap bitmap = Bitmap.createBitmap(
view.getMeasuredWidth(),
view.getMeasuredHeight(),
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Drawable bgDrawable = newLinearLayout.getBackground();
if (bgDrawable != null)
bgDrawable.draw(canvas);
else
canvas.drawColor(Color.WHITE);
view.draw(canvas);
Matrix matrix = new Matrix();
// resize the bit map
matrix.postScale(1.0f, 1.0f);
// recreate the new Bitmap
Bitmap resizedBitmap = null;
resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0,
bitmap.getWidth(), bitmap.getHeight(), matrix, true);
//Canvas resizedCanvas = new Canvas(resizedBitmap);
if (bitmap != null) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
resizedBitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
Bundle parameters = new Bundle();
byte[] data = baos.toByteArray();
parameters.putByteArray("picture", data);
DataKeeper.getInstance().setBundleToPost(parameters);
}
bitmap.recycle();
It shows OutOfMemory exception.I know that this is due to imagesize exceeds its available size.How can i resize image without lossing its quality? I tried to correct this using BitmapFactory.Options. But does not work.How can solve this exception?
Regards
Asha

use this :
BitmapFactory.Options options=new BitmapFactory.Options();
options.inSampleSize = 8;
Bitmap preview_bitmap=BitmapFactory.decodeStream(is,null,options);
for more detail see this link
link

The idea of #Zaz Gmy is correct,
however I don't think the value of inSampleSize should be constant (8) for every image.
This of course will work, but scaling different images with different resolutions on the same scale factor = 8, will cause some of images to have a visible loss of quality.
Instead, the inSimpleSize should be generated based on the target width and height of image.
Android documentation provides a good article on how to deal with this issue.

Please check this tutorial and download the sample project.This will solve your problem
http://developer.sonymobile.com/wp/2011/06/27/how-to-scale-images-for-your-android%E2%84%A2-application/

Color Banding Android Solution

What is possible solution to banded images in Android Activity or in OpenGl.
Look at the answer below.
Hope it Helps

Color Banding Solved ooooooooooyyyyyyyeaaaaaaaaaa
I solved color banding in two phases
1) * when we use the BitmapFactory to decode resources it decodes the resource in RGB565 which shows color banding, instead of using ARGB_8888, so i used BitmapFactory.Options for setting the decode options to ARGB_8888
second problem was whenever i scaled the bitmap it again got banded
2) This was the tough part and took a lot of searching and finally worked
* the method Bitmap.createScaledBitmap for scaling bitmaps also reduced the images to RGB565 format after scaling i got banded images(the old method for solving this was using at least one transparent pixel in a png but no other format like jpg or bmp worked)so here i created a method CreateScaledBitmap to scale the bitmap with the original bitmaps configurations in the resulting scale bitmap(actually i copied the method from a post by logicnet.dk and translated in java)
BitmapFactory.Options myOptions = new BitmapFactory.Options();
myOptions.inDither = true;
myOptions.inScaled = false;
myOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;//important
//myOptions.inDither = false;
myOptions.inPurgeable = true;
Bitmap tempImage =
BitmapFactory.decodeResource(getResources(),R.drawable.defaultart, myOptions);//important
//this is important part new scale method created by someone else
tempImage = CreateScaledBitmap(tempImage,300,300,false);
ImageView v = (ImageView)findViewById(R.id.imageView1);
v.setImageBitmap(tempImage);
// the function
public static Bitmap CreateScaledBitmap(Bitmap src, int dstWidth, int dstHeight, boolean filter)
{
Matrix m = new Matrix();
m.setScale(dstWidth / (float)src.getWidth(), dstHeight / (float)src.getHeight());
Bitmap result = Bitmap.createBitmap(dstWidth, dstHeight, src.getConfig());
Canvas canvas = new Canvas(result);
//using (var canvas = new Canvas(result))
{
Paint paint = new Paint();
paint.setFilterBitmap(filter);
canvas.drawBitmap(src, m, paint);
}
return result;
}
Please correct me if i am wrong.
Also comment if it worked for you.
I am so happy i solved it, Hope it works for you All.
For OpenGl you simply bind the bitmap created after applying upper functions

Android merge two images

I want to merge two images and then save them on the Android SDCard.One is from the camera and one from the resources folder. The problem is that i get this error: Caused by: java.lang.IllegalStateException: Immutable bitmap passed to Canvas constructor. Thanks.
Bitmap bottomImage = BitmapFactory.decodeResource(getResources(),R.drawable.blink);
Bitmap topImage = (Bitmap) data.getExtras().get("data");
// As described by Steve Pomeroy in a previous comment,
// use the canvas to combine them.
// Start with the first in the constructor..
Canvas comboImage = new Canvas(bottomImage);
// Then draw the second on top of that
comboImage.drawBitmap(topImage, 0f, 0f, null);
// bottomImage is now a composite of the two.
// To write the file out to the SDCard:
OutputStream os = null;
try {
os = new FileOutputStream("/sdcard/DCIM/Camera/" + "myNewFileName.png");
bottomImage.compress(CompressFormat.PNG, 50, os);
//Bitmap image.compress(CompressFormat.PNG, 50, os);
} catch(IOException e) {
Log.v("error saving","error saving");
e.printStackTrace();
}
Managed to fix it by simply doing this change:
int w = bottomImage.getWidth();
int h = bottomImage.getHeight();
Bitmap new_image = Bitmap.createBitmap(w, h ,bottomImage.getConfig());
The problem now is that it doesn't saves the image. Do you know why?

This will help you =)
Edit: (embed answer from link)
the only static "constructor" for Bitmap returning a mutable one is:
(Class: Bitmap) public static Bitmap createBitmap(int width, int
height, boolean hasAlpha)
Returns: a mutable bitmap with the specified width and height.
So you could work with getPixels/setPixels or like this:
Bitmap bitmapResult = bm.createBitmap(widthOfOld, heightOfOld, hasAlpha);
Canvas c = new Canvas();
c.setDevice(bitmapResult); // drawXY will result on that Bitmap
c.drawBitmap(bitmapOld, left, top, paint);
how to get the drawable from Bitmap: by using the BitmapDrawable-Subclass which extends Drawable, like this:
Bitmap myBitmap = BitmapFactory.decode(path);
Drawable bd = new BitmapDrawable(myBitmap);

The bitmap you are retrieving is immutable, meaning it can't be modified. Although it doesn't specify on the Canvas page that the constructor needs a mutable bitmap, it does.
To create a mutable bitmap, you can use this method.

Loading a resource to a mutable bitmap

I am loading a bitmap from a resource like so:
Bitmap mBackground = BitmapFactory.decodeResource(res,R.drawable.image);
What I want to do is make some changes to the bitmap before It gets drawn to the main canvas in my draw method (As it would seem wasteful to repeat lots of drawing in my main loop when it isn't going to change). I am making the changes to the bitmap with the following:
Canvas c = new Canvas(mBackground);
c.drawARGB(...); // etc
So naturally I get an exception
java.lang.IllegalStateException: Immutable bitmap passed to Canvas constructor
So to avoid that I made a copy of the bitmap so that it is mutable
Bitmap mBackground = BitmapFactory.decodeResource(res,R.drawable.image).copy(Bitmap.Config.ARGB_8888, true);
Which avoid the problem however it sometimes causes OutOfMemoryExceptions, do know any better ways of achieving what I want?

Use decodeResource(Resources res, int id, BitmapFactory.Options opts) and specify inMutable in the options.
http://developer.android.com/reference/android/graphics/BitmapFactory.html

You'd better use RapidDecoder.
import rapid.decoder.BitmapDecoder;
Bitmap mBackground = BitmapDecoder.from(res, R.drawable.image)
.mutable().decode();
Works for API level 8.

Instad of yours:
Bitmap mBackground = BitmapFactory.decodeResource(res,R.drawable.image);
Use:
BitmapFactory.Options options = new BitmapFactory.Options();
options.inMutable = true;
Bitmap mBackground = BitmapFactory.decodeResource(res,R.drawable.image, options);