android加载大图片

最新推荐文章于 2024-04-02 13:36:40 发布

原创最新推荐文章于 2024-04-02 13:36:40 发布 · 174 阅读

0 ·

CC 4.0 BY-SA版权

android 专栏收录该内容

103 篇文章

订阅专栏

本文介绍了一种在Android应用中优化大尺寸图片加载的方法。通过设置BitmapFactory.Options参数inJustDecodeBounds为true来先获取图片尺寸，然后计算合适的inSampleSize值进行采样，最后加载图片到ImageView组件中。

Options opt = new Options();

       opt.inJustDecodeBounds = true;
       BitmapFactory.decodeFile("sdcard/dog.jpg", opt);

       int imageWidth = opt.outWidth;
       int imageHeight = opt.outHeight;

       Display dp = getWindowManager().getDefaultDisplay();

       int screenWidth = dp.getWidth();
       int screenHeight = dp.getHeight();


       int scale = 1;
       int scaleWidth = imageWidth / screenWidth;
       int scaleHeight = imageHeight / screenHeight;
       if(scaleWidth >= scaleHeight && scaleWidth >= 1){
           scale = scaleWidth;
       }
       else if(scaleWidth < scaleHeight && scaleHeight >= 1){
           scale = scaleHeight;
       }

       opt.inSampleSize = scale;
       opt.inJustDecodeBounds = false;
       Bitmap bm = BitmapFactory.decodeFile("sdcard/dog.jpg", opt);

       ImageView iv = (ImageView) findViewById(R.id.iv);
       iv.setImageBitmap(bm);