Android 如何创建运行时缩略图

Android 如何创建运行时缩略图

java
Bitmap createThumbnail(byte[] imageData, int width, int height) {
    // 加载原始图像数据到内存
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeByteArray(imageData, 0, imageData.length, options);
    // 计算缩放比例
    int sampleSize = calculateSampleSize(options.outWidth, options.outHeight, width, height);
    options.inSampleSize = sampleSize;
    options.inJustDecodeBounds = false;
    // 解码为缩略图
    return BitmapFactory.decodeByteArray(imageData, 0, imageData.length, options);
}
int calculateSampleSize(int originalWidth, int originalHeight, int targetWidth, int targetHeight) {
    int sampleSize = 1;
    if (originalHeight > targetHeight || originalWidth > targetWidth) {
        int halfHeight = originalHeight / 2;
        int halfWidth = originalWidth / 2;
        while ((halfHeight / sampleSize) >= targetHeight && (halfWidth / sampleSize) >= targetWidth) {
            sampleSize *= 2;
        }
    }
    return sampleSize;
}

java
Bitmap createThumbnail(String imagePath, int width, int height) {
    return ThumbnailUtils.createImageThumbnail(imagePath, MediaStore.Images.Thumbnails.MINI_KIND);
}