读取SD卡图片 转化Bitmap

原地址http://my.oschina.net/guandongchen/blog/100283

public static Bitmap convertToBitmap(String path, int w, int h) {          BitmapFactory.Options opts = new BitmapFactory.Options();      // 设置为ture只获取图片大小        opts.inJustDecodeBounds = true;         opts.inPreferredConfig = Bitmap.Config.ARGB_8888;         // 返回为空        BitmapFactory.decodeFile(path, opts);       int width = opts.outWidth;        int height = opts.outHeight;        float scaleWidth = 0.f, scaleHeight = 0.f;        if (width > w || height > h) {           // 缩放           scaleWidth = ((float) width) / w;           scaleHeight = ((float) height) / h;       }      opts.inJustDecodeBounds = false;        float scale = Math.max(scaleWidth, scaleHeight);         opts.inSampleSize = (int)scale;         WeakReference<Bitmap> weak = new WeakReference<Bitmap>(BitmapFactory.decodeFile(path, opts));        return Bitmap.createScaledBitmap(weak.get(), w, h, true);      }