Android开发之图片压缩实现方法分析

public static Bitmap ChangeXY(Scenic scenic, Activity activity){
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 6;
    options.inPreferredConfig = Bitmap.Config.RGB_565;
    options.inPurgeable = true;
    options.inInputShareable = true;
    Bitmap bitmap = BitmapFactory.decodeResource(activity.getResources(),scenic.getImageId(),options);
    if (bitmap.getRowBytes() * bitmap.getHeight() > 1024 ){
      bitmap = compressImage(bitmap);
    }
    return bitmap;
}

private static Bitmap compressImage(Bitmap image) {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    image.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中
    int options = 100;
    while ( baos.toByteArray().length / 1024>100) { //循环判断如果压缩后图片是否大于100kb,大于继续压缩
      baos.reset();//重置baos即清空baos
      image.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%，把压缩后的数据存放到baos中
      options -= 50;//每次都减少10
    }
    ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//把压缩后的数据baos存放到ByteArrayInputStream中
    Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);//把ByteArrayInputStream数据生成图片
    return bitmap;
}