ImageView加载大图片解决OOM错误的问题,使用optio

 编码过程中如果Imageview加载大图片的时候,有可能会出现oom错误,那么就需要修改BitmapFactory.Options options = new BitmapFactory.Options(),的options参数来处理图片,让图片适当的缩放来正确的显示.

代码如下

public void loadBigImage(View view) {

ImageView imageView =this.findViewById(R.id.image_container);

    BitmapFactory.Options options =new BitmapFactory.Options();

    //If set to true, the decoder will return null (no bitmap)

    //设置为true以后呢，不是真的载入到内存中，只是获取到图片的相关信息

    options.inJustDecodeBounds =true;

    BitmapFactory.decodeResource(getResources(),R.mipmap.test_pic,options);

    int width = options.outWidth;//得到资源文件中图片的宽度

    int height = options.outHeight;//得到资源文件中图片的高度

    int measuredWidth = imageView.getMeasuredWidth();//获得控件的宽度

    int measuredHeight = imageView.getMeasuredHeight();//多的控件的高度

    Log.d(TAG,"width -- > " + width +" measure width -- > " + measuredWidth);

    Log.d(TAG,"measuredWidth -- > " + measuredWidth +" measuredHeight  -- > " + measuredHeight );

    int sampleSize;//缩放的倍数  如果是4,图片会缩放为原来的四分之一

    if(width < measuredWidth || height < measuredHeight) {

//如果图片的高度或者宽度小于控件的高度或宽度,则不用sampleSize设置为1,正常显示

sampleSize =1;

    }else {

        int scaleX = width / measuredWidth;

        int scaleY = height / measuredHeight;

        sampleSize = scaleX > scaleY ? scaleX : scaleY;//那个商大用那个,防止图片变形或挤压

    }

Log.d(TAG,"sampleSize -- > " + sampleSize);

    options.inSampleSize = sampleSize;

    //If set to true, the decoder will return null (no bitmap)

    //要变成false了，因为真的要载入到内存中了

    options.inJustDecodeBounds =false;

    Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.mipmap.test_pic,options);

    imageView.setImageBitmap(bitmap);

}