避免位图内存不足错误的建议 [英] Suggestions to avoid bitmap Out of Memory error

问题描述

我正在开发一个安卓应用程序.该应用程序有一个包含大量图像的视图.我有一个错误，我会尽量提供尽可能多的信息，希望有人能给我一些建议.

I am working on an android application. The application has a view containing lots of image. I had an error, I will try to give as much information as possible hoping someone can give me some suggestions.

该应用程序在所有本地测试中都运行良好.但是，我收到了很多来自用户的崩溃:java.lang.OutOfMemoryError:位图大小超出 VM 预算

The application was working great on all the local testings. However, I received lots of crashes from users: java.lang.OutOfMemoryError: bitmap size exceeds VM budget

这是堆栈跟踪

0       java.lang.OutOfMemoryError: bitmap size exceeds VM budget
1   at  android.graphics.Bitmap.nativeCreate(Native Method)
2   at  android.graphics.Bitmap.createBitmap(Bitmap.java:507)
3   at  android.graphics.Bitmap.createBitmap(Bitmap.java:474)
4   at  android.graphics.Bitmap.createScaledBitmap(Bitmap.java:379)
5   at  android.graphics.BitmapFactory.finishDecode(BitmapFactory.java:498)
6   at  android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:473)
7   at  android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:336)
8   at  android.graphics.BitmapFactory.decodeResource(BitmapFactory.java:359)
9   at  android.graphics.BitmapFactory.decodeResource(BitmapFactory.java:385)

我最大的问题是即使在旧设备上我也无法在本地重现该问题.

My biggest problem is that I was not able to reproduce the issue locally even on old devices.

我已经实施了很多方法来尝试解决这个问题:

I have implemented lots of things to try to resolve this:

1. 无内存泄漏:我确保根本没有内存泄漏.当我不需要它们时，我删除了它们.我还回收了所有位图并确保垃圾收集器正常工作.我在 onDestroy() 方法
中实现了所有必要的步骤
2. 图像大小正确缩放:在获取图像之前，我先获取其尺寸并计算inSampleSize.
3. 堆大小:我还在获取图像之前检测最大堆大小，并确保有足够的空间.如果不够，我会相应地重新缩放图像.

1. No memory leaks: I made sure there is no memory leaks at all. I removed the views when I dont need them. I also recycled all the bitmaps and made sure the garbage collector is working as it should. And I implemented all the necessary steps in the onDestroy() method
2. Image size scaled correctly: Before getting the image I get its dimension and calculate the inSampleSize.
3. Heap size: I also detect the Max Heap size before getting the image and make sure there is enough space. If there is not enough I rescale the image accordingly.

计算正确 inSampleSize 的代码

public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight)
   {
      // Raw height and width of image
      final int height = options.outHeight;
      final int width = options.outWidth;
      int inSampleSize = 1;

      if(height > reqHeight || width > reqWidth)
      {
         if(width > height)
         {
            inSampleSize = Math.round((float) height / (float) reqHeight);
         }
         else
         {
            inSampleSize = Math.round((float) width / (float) reqWidth);
         }
      }
      return inSampleSize;
   }

获取位图的代码

    // decodes image and scales it to reduce memory consumption
   private static Bitmap decodeFile(File file, int newWidth, int newHeight)
   {// target size
      try
      {

         Bitmap bmp = MediaStore.Images.Media.getBitmap(getContext().getContentResolver(), Uri.fromFile(file));
         if(bmp == null)
         {
            // avoid concurrence
            // Decode image size
            BitmapFactory.Options option = new BitmapFactory.Options();

            // option = getBitmapOutput(file);

            option.inDensity = res.getDisplayMetrics().densityDpi < DisplayMetrics.DENSITY_HIGH ? 120 : 240;
            option.inTargetDensity = res.getDisplayMetrics().densityDpi;

            if(newHeight > 0 && newWidth > 0) 
                option.inSampleSize = calculateInSampleSize(option, newWidth, newWidth);

            option.inJustDecodeBounds = false;
            byte[] decodeBuffer = new byte[12 * 1024];
            option.inTempStorage = decodeBuffer;
            option.inPurgeable = true;
            option.inInputShareable = true;
            option.inScaled = true;

            bmp = BitmapFactory.decodeStream(new FileInputStream(file), null, option);
            if(bmp == null)
            {
               return null;
            }

         }
         else
         {
            int inDensity = res.getDisplayMetrics().densityDpi < DisplayMetrics.DENSITY_HIGH ? 120 : 240;
            int inTargetDensity = res.getDisplayMetrics().densityDpi;
            if(inDensity != inTargetDensity)
            {
               int newBmpWidth = (bmp.getWidth() * inTargetDensity) / inDensity;
               int newBmpHeight = (bmp.getHeight() * inTargetDensity) / inDensity;
               bmp = Bitmap.createScaledBitmap(bmp, newBmpWidth, newBmpHeight, true);
            }
         }

         return bmp;
      }
      catch(Exception e)
      {
         Log.e("Error calling Application.decodeFile Method params: " + Arrays.toString(new Object[]{file }), e);
      }
      return null;
   }

根据旧设备的堆大小计算图像大小的代码

private void calculateImagesSize()
   {
      // only for android older than HoneyComb that does not support large heap
      if(Build.VERSION.SDK_INT < Constants.HONEYCOMB)
      {
         long maxHeapSize = Runtime.getRuntime().maxMemory();
         long maxImageHeap = maxHeapSize - 10485760;
         if(Application.getResource().getDisplayMetrics().densityDpi >= DisplayMetrics.DENSITY_XHIGH)
         {
            maxImageHeap -= 12 * 1048576;
         }
         if(maxImageHeap < (30 * 1048576))
         {
            int screenHeight = Math.min(Application.getResource().getDisplayMetrics().heightPixels, Application.getResource()
               .getDisplayMetrics().widthPixels);
            long maxImageSize = maxImageHeap / 100;
            long maxPixels = maxImageSize / 4;
            long maxHeight = (long) Math.sqrt(maxPixels / 1.5);
            if(maxHeight < screenHeight)
            {
               drawableHeight = (int) maxHeight;
               drawableWidth = (int) (drawableHeight * 1.5);
            }
         }
      }
   }

我认为问题出在堆上，也许有时操作系统不允许应用程序使用 maxheapsize.另外，我最大的问题是我无法重现该问题，因此当我尝试修复时，我必须稍等一下，看看用户是否仍然收到错误消息.

I think the problem is with the Heap, maybe sometimes the os doesn't allow the application to use the maxheapsize. Also my biggest problem is that I was not able to reproduce the issue, so when I try a fix I have to wait a little to see if users are still getting the error.

我还能尝试避免内存不足问题吗?任何建议将不胜感激.非常感谢

What more could I try to avoid Out of memory issues? Any suggestions would be greatly appreciated. Thanks a lot

推荐答案

只需使用此功能解码...这是您错误的完美解决方案..因为我也遇到了同样的错误并且我得到了这个解决方案..

just use this function to decode...this is perfect solution for your error..because i also getting same error and i got this solution..

public static Bitmap decodeFile(File f,int WIDTH,int HIGHT){
     try {
         //Decode image size
         BitmapFactory.Options o = new BitmapFactory.Options();
         o.inJustDecodeBounds = true;
         BitmapFactory.decodeStream(new FileInputStream(f),null,o);

         //The new size we want to scale to
         final int REQUIRED_WIDTH=WIDTH;
         final int REQUIRED_HIGHT=HIGHT;
         //Find the correct scale value. It should be the power of 2.
         int scale=1;
         while(o.outWidth/scale/2>=REQUIRED_WIDTH && o.outHeight/scale/2>=REQUIRED_HIGHT)
             scale*=2;

         //Decode with inSampleSize
         BitmapFactory.Options o2 = new BitmapFactory.Options();
         o2.inSampleSize=scale;
         return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
     } catch (FileNotFoundException e) {}
     return null;
 }

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