如何在Android上保存具有自定义质量级别的JPEG图像

Question

在Android上，如何以30%的质量将图像文件保存为JPEG格式？

在标准Java语言中，我将使用ImageIO将图像读取为BufferedImage，然后使用IIOImage实例http://www.universalwebservices.net/web-programming-resources/java/adjust-jpeg-image-compression-quality-when-saving-images-in-java将其保存为JPEG文件。然而，看起来安卓缺少javax.imageio包。

Answer 1

通过调用compress并设置第二个参数，可以将位图存储为JPEG格式：

    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);

​

Answer 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();
}

Answer 3

@Phyrum Tea是好的，只是别忘了关闭一切

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();