作物和调整大小的Andr​​oid图像 [英] Crop and resize an image in Android

问题描述

我是从磁盘读取图像，并在的ListView 行内显示出来。图像文件是不是需要什么样的的ImageView 的行内显示更大。因为我需要缓存位图在RAM中的快速访问，我想他们只是一样大的的ImageView S（85x85 DIP）

I am reading an image from disk and displaying it inside of a row in a ListView. The image files are larger than what needs to be displayed inside the ImageView of the rows. Since I need to cache the bitmaps in RAM for faster access I would like them to only be as large as the ImageViews (85x85 dip)

现在我读文件中以

位= BitmapFactory.de codeFILE（文件）;

bitmap = BitmapFactory.decodeFile(file);

和ImageView的负责缩放和剪切它

and the ImageView is responsible for scaling and cropping it

安卓scaleType =centerCrop

android:scaleType="centerCrop"

AFAIK这是保持在内存中整个位图（因为我缓存吧XD），这是不好的。

AFAIK this is keeping the entire bitmap in memory (because I cached it XD) and that is bad

我怎样才能删除该ImageView的这个责任，做作物+规模在加载文件？所有的位图将在85x85倾角被显示和需要centerCrop'

How can I remove this responsibility from the ImageView and do the crop + scale while loading the file? All the bitmaps will be displayed at 85x85 dip and need to be 'centerCrop'

推荐答案

您可以找到您的图片加载前的尺寸，裁剪和缩放：

You can find out the dimensions of your pictures before loading, cropping and scaling:

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

    Bitmap bmo = BitmapFactory.decodeFile(file.getAbsolutePath(), options);

然后将其加载在试样尺寸：

Then load it in sample size:

...
options.inSampleSize = 1/2;
bmo = BitmapFactory.decodeFile(file.getAbsolutePath(), options);

...
 = Bitmap.createScaledBitmap(bmo, dW, dH, false);

别忘了回收临时位图或你会得到OOME。

don't forget to recycle temporary bitmaps or you'll get OOME.

bmo.recycle();

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