加载大背景图像时的OutOfMemory [英] OutOfMemory when loading large Background Image

问题描述

我正在使用 android：background 为android布局提供背景图片。

放置一些图像后我得到了这个例外：

I am using android:background to give a background image to android layout.
After putting some images I get this exception :

08-24 00:40:19.237: E/dalvikvm-heap(8533): Out of memory on a 36000016-byte allocation.

如何在android上使用大图像作为背景？

我可以扩展应用程序堆内存吗？还是不好做？

how can I use large images as backgrounds on android?
can I expand the application heap memory? or is it something not good to do ?

推荐答案

请查看我的相关问题：

高分辨率图片 - OutOfMemoryError

High resolution Image - OutOfMemoryError

尽量使背景图像尽可能小，尽量减少应用程序的内存使用量。

Try to minimize the memory usage of your application by keeping the background image as small as possible.

这个可以通过以下方式完成：

This can be done via:

• 裁剪图像以使其适合屏幕


• 压缩图像进一步（使用例如photoshop）甚至在应用程序中使用它之前


• 使用下面的方法加载你的位图


• 再次回收位图没有loger需要它


• 确保你没有在内存中保留多个实例


• 使用位图后将引用设置为null

• cropping the image so that it fits the screen
• compress the image further (use e.g. photoshop) before even using it in the app
• use the below method to load your bitmap
• recycle the bitmap as soon as you no loger need it
• make sure you do not keep multiple instances of it in memory
• set the reference to null after using the bitmap

确保您设置为背景的图像已正确加载（例如，裁剪尺寸，例如适合屏幕尺寸），并在不再需要时立即从存储器中释放。

确保你有内存中只有一个Bitmap实例。显示后，调用 recycle（）并将引用设置为null。

Make sure you have only one instance of your Bitmap in memory. After displaying it, call recycle() and set your reference to null.

这是加载图片的方法：

public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

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) {

        // Calculate ratios of height and width to requested height and width
        final int heightRatio = Math.round((float) height / (float) reqHeight);
        final int widthRatio = Math.round((float) width / (float) reqWidth);

        // Choose the smallest ratio as inSampleSize value, this will guarantee
        // a final image with both dimensions larger than or equal to the
        // requested height and width.
        inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
    }

    return inSampleSize;
}

感谢 Adam Stelmaszczyk 这段美丽的代码。

这篇关于加载大背景图像时的OutOfMemory的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！