android 图片操作

缩放

public static void resize(Bitmap bitmap, File outputFile, int maxWidth, int maxHeight) {
    try {
        int bitmapWidth = bitmap.getWidth();
        int bitmapHeight = bitmap.getHeight();
        // 图片大于最大高宽，按大的值缩放
        if (bitmapWidth > maxHeight || bitmapHeight > maxWidth) {
            float widthScale = maxWidth * 1.0f / bitmapWidth;
            float heightScale = maxHeight * 1.0f / bitmapHeight;
           //取小值
            float scale = Math.min(widthScale, heightScale);
            Matrix matrix = new Matrix();
            //图片变换处理 缩放
            matrix.postScale(scale, scale);
            bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmapWidth, bitmapHeight, matrix, false);
        }    
        FileOutputStream out = new FileOutputStream(outputFile);
        try {
            bitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

//保存图片

public static void saveBitmap(String outputPath, Bitmap bitmap) {
    // save image
    FileOutputStream out = null;
    try {
        out = new FileOutputStream(outputPath);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (out != null) {
                out.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

//base64转bitmap

public static Bitmap base64tobitmap(String image) {
    if (TextUtils.isEmpty(image)) {
        return null;
    }
    byte[] bytes = Base64.decode(image.getBytes(), Base64.DEFAULT);

    Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);

    return bitmap;
}

/**
 * 加载本地图片
 * 
 * @param url
 * @return
 */
public static Bitmap getLoacalBitmap(String url) {
   try {
      FileInputStream fis = new FileInputStream(url);
      return BitmapFactory.decodeStream(fis); // /把流转化为Bitmap图片
   } catch (Exception e) {
      e.printStackTrace();
      return null;
   }
}    
//旋转拍照生成的图片的方向
public static Bitmap getBitmapByUrl(byte[] data,int fangxiang) {

      Bitmap bitmap = null;
      try {

         bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
         // 根据拍摄的方向旋转图像（纵向拍摄时要需要将图像选择90度)
         Matrix matrix = new Matrix();
         matrix.setRotate(fangxiang);
         bitmap = FileUtils.comp(Bitmap
                .createBitmap(bitmap, 0, 0, bitmap.getWidth(),
                      bitmap.getHeight(), matrix, true));

      } catch (Exception e) {
         e.printStackTrace();
         bitmap.recycle();
         bitmap = null;
         System.gc();
      } finally {
         if (fis != null) {
            try {
               fis.close();
            } catch (IOException e) {
               e.printStackTrace();
            }
            fis = null;
         }
      }

      return bitmap;
   }