How to save a JPEG image on Android with a custom

问题:

On Android, how do I save an image file as a JPEG at 30% quality?

In standard Java, I would use ImageIO to read the image as a BufferedImage, then save it as a JPEG file using an IIOImage instance: http://www.universalwebservices.net/web-programming-resources/java/adjust-jpeg-image-compression-quality-when-saving-images-in-java. It appears, however, that Android lacks the javax.imageio package.

回答1:

You can store your bitmap in the JPEG format by calling compress and setting the second parameter:

    Bitmap bm2 = createBitmap();
    OutputStream stream = new FileOutputStream("/sdcard/test.jpg");
    /* Write bitmap to file using JPEG and 80% quality hint for JPEG. */
    bm2.compress(CompressFormat.JPEG, 80, stream);

回答2:

InputStream in = new FileInputStream(file);
try {
    Bitmap bitmap = BitmapFactory.decodeStream(in);
    File tmpFile = //...;
    try {
        OutputStream out = new FileOutputStream(tmpFile);
        try {
            if (bitmap.compress(CompressFormat.JPEG, 30, out)) {
                { File tmp = file; file = tmpFile; tmpFile = tmp; }
                tmpFile.delete();
            } else {
                throw new Exception("Failed to save the image as a JPEG");
            }
        } finally {
            out.close();
        }
    } catch (Throwable t) {
        tmpFile.delete();
        throw t;
    }
} finally {
    in.close();
}

回答3:

@Phyrum Tea is good only do not forget close everything

InputStream in = new FileInputStream(context.getFilesDir()+"image.jpg");
            Bitmap bm2 = BitmapFactory.decodeStream(in);
            OutputStream stream = new FileOutputStream(String.valueOf(context.getFilesDir()+pathImage+"/"+idPicture+".jpg"));
            bm2.compress(Bitmap.CompressFormat.JPEG, 50, stream);
            stream.close();
            in.close();