Android-创建一个仅包含所有图像文件夹名称的列表

Question

我被困在我的活动生成包含拇指图像的列表和包含来自SD卡的图像的所有文件夹的名称的位置。 1.如何仅使用图像过滤那些文件夹？ 2.如何从文件夹中的第一张图像获取拇指图像？

Answer 1

How do i filter only those folders with the images

您可以检查文件夹中文件的扩展名，看看它们是否属于图像类型。

How do i get the thumb images from the first image in the folder

使用以下

将文件压缩为更小的尺寸

public Bitmap compressBitmap(String filePath, int requiredSize)
{
    File file = new File(filePath);
    if (file.exists())
    {
        try
        {

            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeFile(filePath, o);

            // The new size we want to scale to
            final int REQUIRED_SIZE = requiredSize;

            // Find the correct scale value. It should be the power of 2.
            int width_tmp = o.outWidth, height_tmp = o.outHeight;
            int scale = 1;
            while (true)
            {
                if (width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE)
                {
                    break;
                }
                width_tmp /= 2;
                height_tmp /= 2;
                scale *= 2;
            }

            // Decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            return BitmapFactory.decodeStream(new FileInputStream(file), null, o2);
        }

        catch (FileNotFoundException e)
        {
            e.printStackTrace();
        }

        return null;
    }

    return null;
}