使用这些代码为每一个图像在选择从SdCard或可绘制转换位图对象。

Resources res = getResources();
WindowManager window = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
Display display = window.getDefaultDisplay();
@SuppressWarnings("deprecation")
int width = display.getWidth();
@SuppressWarnings("deprecation")
int height = display.getHeight();
try {
    if (bitmap != null) {
        bitmap.recycle();
        bitmap = null;
        System.gc();
    }
    bitmap = Bitmap.createScaledBitmap(BitmapFactory
        .decodeFile(ImageData_Path.get(img_pos).getPath()),
        width, height, true);
} catch (OutOfMemoryError e) {
    if (bitmap != null) {
        bitmap.recycle();
        bitmap = null;
        System.gc();
    }
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPreferredConfig = Config.RGB_565;
    options.inSampleSize = 1;
    options.inPurgeable = true;
    bitmapBitmap.createScaledBitmap(BitmapFactory.decodeFile(ImageData_Path.get(img_pos)
        .getPath().toString(), options), width, height,true);
}
return bitmap;

使用ImageData_Path.get(img_pos). getpath()的图像路径instend。

我花了一整天的时间来测试这些解决方案，唯一对我有用的是上面的获取图像和手动调用GC的方法，我知道这是不必要的，但当我把应用程序置于繁重的负载测试下时，这是唯一有效的方法。我的应用程序有一个缩略图列表在列表视图(让说活动a)，当你点击其中一个图像，它带你到另一个活动(让说活动B)，显示该项目的主图像。当我在两个活动之间来回切换时，我最终会得到OOM错误，应用程序将强制关闭。

当我走到列表视图一半的时候它就崩溃了。

现在，当我在活动B中实现以下内容时，我可以毫无问题地遍历整个列表视图，并继续下去……而且速度很快。

@Override
public void onDestroy()
{   
    Cleanup();
    super.onDestroy();
}

private void Cleanup()
{    
    bitmap.recycle();
    System.gc();
    Runtime.getRuntime().gc();  
}

我需要加载一个大尺寸的图像到位图，我使用Glide来解决这个问题。首先用BitmapFactory检查图像大小。选项使用injstdecodebounds设置为true，然后使用Glide获取位图对象。我使用分析器来检查内存使用情况，但我没有看到任何内存峰值，就像我使用BitmapFactory.decodeFile()时那样。 我是用c#写的，因为我使用Xamarin，所以需要在Java中使用一点小调整。 Glide库文档

private Bitmap DecodeFile(File file) {
        // Decode image size
        BitmapFactory.Options options = new BitmapFactory.Options();
        
        // setting inJustDecodeBounds to true won't load the file into memory, 
        // but gives you the actual file size.
        options.InJustDecodeBounds = true;
        BitmapFactory.decodeStream(new FileInputStream(file), null, options);
        int actualWidth = options.OutWidth;
        int actualHeight = options.OutHeight;
                
        var ratio = (double)actualHeight / actualWidth;

        // Default to 800 x 600. changed the size whatever you need.
        var desiredWidth = 800;
        var desiredHeight = 600;

        if(actualHeight > actualWidth)
        {
            var ratio = (double)actualWidth / actualHeight;
            var futureTarget = Glide.With(Application.Context)
                .AsBitmap()
                .Load(file)
                .SetDiskCacheStrategy(DiskCacheStrategy.None)
                .SkipMemoryCache(true)
                .Submit((int)(desiredWidth * ratio), desiredWidth);
            bitmap = futureTarget.Get() as Bitmap;
        }
        else
        {
            var ratio = (double)actualHeight / actualWidth;
            var futureTarget = Glide.With(Application.Context)
                .AsBitmap()
                .Load(file)
                .SetDiskCacheStrategy(DiskCacheStrategy.None)
                .SkipMemoryCache(true)
                .Submit(desiredWidth, (int)(desiredWidth * ratio));
            bitmap = futureTarget.Get() as Bitmap;
        }return bitmap;}

这段代码将有助于从可绘制的图中加载大的位图

public class BitmapUtilsTask extends AsyncTask<Object, Void, Bitmap> {

    Context context;

    public BitmapUtilsTask(Context context) {
        this.context = context;
    }

    /**
     * Loads a bitmap from the specified url.
     * 
     * @param url The location of the bitmap asset
     * @return The bitmap, or null if it could not be loaded
     * @throws IOException
     * @throws MalformedURLException
     */
    public Bitmap getBitmap() throws MalformedURLException, IOException {       

        // Get the source image's dimensions
        int desiredWidth = 1000;
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;

        BitmapFactory.decodeResource(context.getResources(), R.drawable.green_background , options);

        int srcWidth = options.outWidth;
        int srcHeight = options.outHeight;

        // Only scale if the source is big enough. This code is just trying
        // to fit a image into a certain width.
        if (desiredWidth > srcWidth)
            desiredWidth = srcWidth;

        // Calculate the correct inSampleSize/scale value. This helps reduce
        // memory use. It should be a power of 2
        int inSampleSize = 1;
        while (srcWidth / 2 > desiredWidth) {
            srcWidth /= 2;
            srcHeight /= 2;
            inSampleSize *= 2;
        }
        // Decode with inSampleSize
        options.inJustDecodeBounds = false;
        options.inDither = false;
        options.inSampleSize = inSampleSize;
        options.inScaled = false;
        options.inPreferredConfig = Bitmap.Config.ARGB_8888;
        options.inPurgeable = true;
        Bitmap sampledSrcBitmap;

        sampledSrcBitmap =  BitmapFactory.decodeResource(context.getResources(), R.drawable.green_background , options);

        return sampledSrcBitmap;
    }

    /**
     * The system calls this to perform work in a worker thread and delivers
     * it the parameters given to AsyncTask.execute()
     */
    @Override
    protected Bitmap doInBackground(Object... item) {
        try { 
          return getBitmap();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

嗨，请访问链接http://developer.android.com/training/displaying-bitmaps/index.html

或者只是尝试用给定的函数检索位图

private Bitmap decodeBitmapFile (File f) {
    Bitmap bitmap = null;
    try {
        // Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options ();
        o.inJustDecodeBounds = true;

        FileInputStream fis = new FileInputStream (f);
        try {
            BitmapFactory.decodeStream (fis, null, o);
        } finally {
            fis.close ();
        }

        int scale = 1;
        for (int size = Math.max (o.outHeight, o.outWidth); 
            (size>>(scale-1)) > IMAGE_MAX_SIZE; ++scale);

        // Decode with input-stram SampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options ();
        o2.inSampleSize = scale;
        fis = new FileInputStream (f);
        try {
            bitmap  = BitmapFactory.decodeStream (fis, null, o2);
        } finally {
            fis.close ();
        }
    } catch (IOException e) {
    }
    return bitmap ;
}

这将获得适当的位图并减少内存消耗

JAVA

Bitmap bm = null;

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

FileInputStream fis = new FileInputStream(file);
BitmapFactory.decodeStream(fis, null, bmpOption);
fis.close();

int scale = 1;

if (bmpOption.outHeight > IMAGE_MAX_SIZE || bmpOption.outWidth > IMAGE_MAX_SIZE) {
    scale = (int)Math.pow(2, (int) Math.ceil(Math.log(IMAGE_MAX_SIZE / 
       (double) Math.max(bmpOption.outHeight, bmpOption.outWidth)) / Math.log(0.5)));
}

BitmapFactory.Options bmpOption2 = new BitmapFactory.Options();
bmpOption2.inSampleSize = scale;
fis = new FileInputStream(file);
bm = BitmapFactory.decodeStream(fis, null, bmpOption2);
fis.close();

科特林

val bm:Bitmap = null
val bmpOption = BitmapFactory.Options()
bmpOption.inJustDecodeBounds = true
val fis = FileInputStream(file)
BitmapFactory.decodeStream(fis, null, bmpOption)
fis.close()
val scale = 1
if (bmpOption.outHeight > IMAGE_MAX_SIZE || bmpOption.outWidth > IMAGE_MAX_SIZE)
{
  scale = Math.pow(2.0, Math.ceil((Math.log((IMAGE_MAX_SIZE / Math.max(bmpOption.outHeight, bmpOption.outWidth) as Double)) / Math.log(0.5))).toInt().toDouble()).toInt()
}
val bmpOption2 = BitmapFactory.Options()
bmpOption2.inSampleSize = scale
fis = FileInputStream(file)
bm = BitmapFactory.decodeStream(fis, null, bmpOption2)
fis.close()