回收位图不会释放内存 [英] Recycling Bitmap does not free memory

问题描述

我在TabHost中有一个Activity，还有其他3个活动.因此，它们始终处于活动状态(或处于暂停"状态).

I have an Activity in a TabHost with 3 other activities. Hence, these are always alive (or in "on pause" state).

第一个活动有四个不同的图像(每个图像约250kb)，它们正在检索大量内存(约80MB.请指出，我加载了屏幕所需的最小尺寸，并且使用layout_weight会有所帮助)，所以我想最小化所需的内存量.

The first activity has four different images (~250kb each) and they are retrieving a lot of memory (around 80MB. Just to point out, I load the minimum size needed for the screen and I'm using layout_weight if that helps), so I want to minimize the amount of memory which is needed.

我已经尝试删除处于OnPause状态的图像，然后再次将它们设置为OnResume，但是我没有运气，这是我正在尝试做的一个例子:

I already tried to delete the images on the OnPause state and set them again on OnResume, but I didn't have luck, this is one example of what I was trying to do:

 imageView.Drawable.Callback = null;
 ((BitmapDrawable)imageView.Drawable).Bitmap.Recycle();
 imageView.Drawable.Dispose();
 imageView.SetImageDrawable(null);
 imageView.SetImageBitmap(null);
 GC.Collect();

我不知道删除OnPause上的Bitmap是否是最好的策略，但是应该可以.我不明白为什么GC不收集ImageView的原因(因为没有外部引用)

I don't know if deleting the Bitmap on OnPause is the best strategy, but it should work. I don't understand why the ImageView isn't collected by the GC (since there are not external references)

编辑 这就是我加载图像的方式.即使我将图像放在xml文件中也不起作用.此外，我不在乎此代码，我只想配置位图.

EDIT This is how I'm loading the images. It doesn't work even if I put the images on the xml file. Besides, I don't care this code, I just want to dispose the bitmaps.

       void SetBackgroundImages(int imageId, int resId, float width, float height) {
        var imageView = FindViewById<ImageView>(imageId);
        using (var bitmap = DecodeSampledBitmapFromResource(Resources, resId, width, height))
            imageView.SetImageBitmap(bitmap);

    }
    public static Bitmap DecodeSampledBitmapFromResource(Resources res, int resId, float reqWidth, float reqHeight) {

    var options = new BitmapFactory.Options {InJustDecodeBounds = true};
    using (var b = BitmapFactory.DecodeResource(res,resId,options)){}
        options.InSampleSize = CalculateInSampleSize(options, reqWidth, reqHeight);
        options.InJustDecodeBounds = false;
        return BitmapFactory.DecodeResource(res, resId, options);
    }

推荐答案

最后，删除图像后调用java.lang.System.gc()达到了目的.

At the end calling to java.lang.System.gc() after deleting the images did the trick.

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