Develop Reference

Android BitmapFactory.decodeFile(path) always returns null

I see that is a lot of solutions related to this issue, but none of this solved my problem.
I try to read image from png file to bitmap (image is very small ~16px so there is no option that I got OutOfMemoryException) using BitmapFactory.decodeFile(path) function.
My file hierarchy is as simple as possible:
-java
--example.com.app
---MainActivity.class
-res
--drawable
---array.png
I launch application from MainActivity and on button click I try to read png image to bitmap.
I try to read image to bitmap in the following ways:
String path = Uri.parse("android.resource://"+R.class.getPackage().getName() +"/drawable/arrow.png").toString();
Bitmap bitmap = BitmapFactory.decodeFile(path);
String path = Uri.parse("android.resource://drawable/arrow.png").toString();
Bitmap bitmap = BitmapFactory.decodeFile(path);
Everytime bitmap is null. Do you know where could be a problem?
Android API 27

Or use the simple method of BitmapFactory
BitmapFactory.decodeResource(getResources(), R.id.arrow);
Or you can use context.getDrawable(R.drawable.arrow) which will return a drawable that is ready to use.
Read more about this here
If you would like to still use the path then use java.nio.file.Paths(folder1, folder2.. .. .)
Read more about this here

You should use decodeResource, below is an example:
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.arrow, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
String imageType = options.outMimeType;
Or use its simple way decodeResource.
BitmapFactory.decodeResource(getResources(), R.id.arrow);

Why the bitmap from res/raw folder is null?

I try to decode a bitmap(1920x1920) from res/raw folder,which is an png resource.I need the full-scale bitmap. I want to use the BimtapFactory.decodeFileDescriptor rather than BitmapFactory.decodeFile||decodeResource because the higher reliability than others to handle OOM:
While I try this code,The bitmap is NULL!!! But the file is not null. I've been playing hard.
Help Please!
Context mCtx=MainActivity.this;
Bitmap bm = null;
//id is the resId in res/raw
AssetFileDescriptor file =mCtx.getResources().openRawResourceFd(R.raw.skin_default_0);
bm = BitmapFactory.decodeFileDescriptor(file.getFileDescriptor(), null,
options);

InputStream bm = getResources().openRawResource(R.raw.splash);
BufferedInputStream bufferedInputStream = new BufferedInputStream(bm);
Bitmap bmp = BitmapFactory.decodeStream(bufferedInputStream);
int nh = (int) (bmp.getHeight() * (512.0 / bmp.getWidth()));
bmp = Bitmap.createScaledBitmap(bmp, 512, nh, true);
view.setImageBitmap(bmp);
Try this code.
Raw folder - keeping the files as uncompressed.
I dont think so , that the BitmapFactory.decodeFileDescriptor will give u efficient result when comparing with the BitmapFactory.decodeStream, Get the inputStream of the file and decode it. if u think the image is too big and u r using many images like this ur app is going to be very heavy, since the raw folder files willnt be compressed. if u want to scaled bitmap use the snippet code that i have added with my code. will give u a better understanding i thnk.
Thanks...

Error:Bitmap size Exceed VM budget, when converting image to ARGB_8888

Here is my code:
File file = new File(Path to Jpeg File size is 700kb);
InputStream in = null;
try {
in = new BufferedInputStream(new FileInputStream(file));
}
catch (Exception e) {
// TODO: handle exception
}
bitmap =BitmapFactory.decodeStream(in);
bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);
Please help i get error in this copy line i want to make its ARGB_8888 image.Need Help :(

You need to reduce the memory usage.
From you code, you first decode stream to one bitmap, and then copy it, which means you create two large bitmap objects.
You don't need to decode and then copy it, you can try
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_8888
// You can try value larger than 1
options.inSampleSize = 2 // If set to a value > 1, requests the decoder to subsample the original image, returning a smaller image to save memory.
// Decode bitmap
bitmap = BitmapFactory.decodeStream(in, null, options)
In this case, there's only one bitmap created. And you set inSampleSize to large values to reduce the loaded bitmap size.

Create a file from drawable

I have a large number of resources in my drawable folder.All are having big size more than 500KB. I have to load all these 25 images all at once in a srollView. As usual I ran out of memory. Is there any way to reduce the size of the image programmatically.
I got this function but it's parameter is a File and I don't know how to create a File from a drawable.
private Bitmap decodeFile(File f){
Bitmap b = null;
try {
//Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream fis = new FileInputStream(f);
BitmapFactory.decodeStream(fis, null, o);
fis.close();
int scale = 1;
if (o.outHeight > IMAGE_MAX_SIZE || o.outWidth > IMAGE_MAX_SIZE) {
scale = Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE / (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
}
//Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
fis = new FileInputStream(f);
b = BitmapFactory.decodeStream(fis, null, o2);
fis.close();
} catch (FileNotFoundException e) {
}
return b;
}
I have to go thorugh this screen cyclically many times after a number of traversal the system is showing Low memory and it is removing the other views in the back from the stack , but I actually need it.
Please help me.

You can open an InputStream from your drawable resource using following code:
InputStream is = getResources().openRawResource(id);
here id is the identifier of your drawable resource. for eg: R.drawable.abc
Now using this input stream you can create a file. If you also need help on how create a file using this input stream then tell me.
Update: to write data in a file:
try
{
File f=new File("your file name");
InputStream inputStream = getResources().openRawResource(id);
OutputStream out=new FileOutputStream(f);
byte buf[]=new byte[1024];
int len;
while((len=inputStream.read(buf))>0)
out.write(buf,0,len);
out.close();
inputStream.close();
}
catch (IOException e){}
}

I like shortcuts so I prefer using this.
For creatting file from drawable see this.
Put this in your build.gradle
compile 'id.zelory:compressor:1.0.4'
And wherever you want to compress the image put
Bitmap compressedImageFile = Compressor.getDefault(context).compressToBitmap(your_file);
README.md provides much more information. Sorry for bringing the answer after 6 years.

bro there are two methods
Easiest one Use some 3rd party library
Or use Bitmap class to scale drawable down
just use Bitmap.createScaledBitmap method to compress drawables
steps :
// Step 1 Load drawable and convert it to bitmap
Bitmap b = BitmapFactory.decodeResource( context , resId )
// Step 2 reScale your Bitmap
Bitmap nBitmap = b.createScaledBitmap( getResources() , newHieght , newWidth , true );
// Step 3 Create a drawable from bitmap
BitmapDrawable drawable = new BitmapDrawable(nBitmap);
I highly recommend you to use 3rd part library because this method is very expensive
like https://github.com/Tourenathan-G5organisation/SiliCompressor

I took cue from #mudit's answer and created the drawable from Input Stream. And later loaded the drawable to the ImageView in the Adapter.
InputStream inputStream = mContext.getResources().openRawResource(R.drawable.your_id);
Bitmap b = BitmapFactory.decodeStream(inputStream);
b.setDensity(Bitmap.DENSITY_NONE);
Drawable d = new BitmapDrawable(b);
mImageView.setImageDrawable(d);
Here is the detailed version of solution

Reading Raw data from Bitmap files

I'm trying to decode a .jpg file into a bitmap and reading the raw data from the Bitmap File.
The following is the code snippet of my app.
File file = new File(Environment.getExternalStorageDirectory(),"test.jpg");
int top = 450;
int left = 0;
int right= 1450;
int bottom = 2592;
int width = right-top;
int height = bottom-left;
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
bitmap = BitmapFactory.decodeFile(file.getAbsolutePath(), options);
Bitmap bitmapScaled = Bitmap.createBitmap(bitmap, top, left, width, height);
bitmap.recycle();
ByteBuffer buffer = ByteBuffer.allocate(width*height*4);
bitmapScaled.copyPixelsToBuffer(buffer);
bitmapScaled.recycle();
File file2 = new File(Environment.getExternalStorageDirectory(),"decodeFile");
FileOutputStream out = new FileOutputStream(file2.getAbsolutePath());
out.write(buffer.array());
In the above snippet, im trying to read the raw data from the Bitmap file into ByteBuffers and storing into a newly created file(decodeFile) in the SDCARD.
When i see the data in the "decodeFile" half of the data will becomes null, and the data is improper.
The above is one type of method of reading the raw data using Bitmap class methods.
When i follow the same thing by using the below code snippet, im getting the correct data.
BitmapRegionDecoder bitmapRegionDecoder = BitmapRegionDecoder.newInstance(file1.getAbsolutePath(), true);
Bitmap bitmap1 = bitmapRegionDecoder.decodeRegion(new Rect(top,left,width,height),options);
ByteBuffer buffer = ByteBuffer.allocate(width*height*4);
bitmapScaled.copyPixelsToBuffer(buffer);
bitmapScaled.recycle();
File file2 = new File(Environment.getExternalStorageDirectory(),"regionFile");
FileOutputStream out = new FileOutputStream(file2.getAbsolutePath());
out.write(buffer.array());
If i use this snippet, i'm getting the correct data. But the drawback of using BitmapRegionDecoder is memory Leakage. The application will lose 1.5 MB of memory everytime, it executes this API. This memory is not possible to get back to the application with GC also.
So can any body please help me how to copy the data from bitmap to another file without losing the data.. It will be very much helpful for me if any body respond to this..
Thanks in advance

See my answer to my own question here
You'll be interest in the onActivityResult method.