How to quickly convert a list of image file paths to a list of bitmaps?
ArrayList<String> imageFileList = new ArrayList<>();
ArrayList<RecentImagesModel> fileInfo = new ArrayList<>();
File targetDirector = new File(/storage/emulated/0/DCIM/Camera/);
if (targetDirector.listFiles() != null) {
File[] files = targetDirector.listFiles();
int i = files.length - 1;
while (imageFileList.size() < 10) {
File file = files[i];
if (file.getAbsoluteFile().toString().trim().endsWith(".jpg")) {
imageFileList.add(file.getAbsolutePath());
} else if (file.getAbsoluteFile().toString().trim().endsWith(".png")) {
imageFileList.add(file.getAbsolutePath());
}
i--;
}
}
String file, filename;
Bitmap rawBmp, proBmp;
int length = imageFileList.size();
for (int i = 0; i < length; i++) {
RecentImagesModel rim = new RecentImagesModel();
file = imageFileList.get(i);
rim.setFilepath(file);
filename = file.substring(file.lastIndexOf("/") + 1);
rim.setName(filename);
rawBmp = BitmapFactory.decodeFile(file);
proBmp = Bitmap.createScaledBitmap(rawBmp, rawBmp.getWidth() / 6, rawBmp.getHeight() / 6, false);
rim.setBitmap(proBmp);
fileInfo.add(rim);
}
When I convert file objects to bitmaps and scale them:
rawBmp = BitmapFactory.decodeFile(file);
proBmp = Bitmap.createScaledBitmap(rawBmp, rawBmp.getWidth() / 6, rawBmp.getHeight() / 6, false);
It takes a long time to process. Is there a way to shorten the process?
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Is there a way to shorten the process?
With your current algorithm, having a smaller list of images.
You could save a lot of time and a lot of memory:
-
Switch from "1/6 of the original image" to "1/4 of the original image" or "1/8 of the original image", then
-
Use a two-parameter
decodeFile()
that acceptsBitmapFactory.Options
, and putinSampleSize
in 2 (for 1/4) or 3 (for 1/8)
In general, loading a whole series of images at once is not a good idea, so I highly recommend that you find a way to load images when and only when you need them. For example, if a user has hundreds of high resolution photos in this directory, you will run into OutOfMemoryError
as you run out of heap space to store hundreds of images.
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