一幅320KB的背景图像大约占用30MB的内存空间

Question

应用程序启动

02-08 20:35:12.105:D/DalvikVM(27962):GC_FOR_ALLOC释放8804K,18%释放53293K/64775K,暂停31ms,总计31ms

02-08 20:35:12.110:I/dalvikvm-heap（27962）：将堆（frag大小写）增长到61.693MB，用于9000016字节分配

02-08 20:35:12.330:I/dalvikvm-heap（27962）：将堆（frag大小写）增长到61.643MB，用于36000016字节分配

02-08 20:35:12.350:D/DalvikVM(27962):GC_CONCURRENT释放0k，5%释放62031k/64775k，暂停11ms+3ms，总计23ms

教程中的函数：

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;
}

 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);
 }

final FrameLayout fr = (FrameLayout) findViewById(R.id.mainmenu_background);
//fr.setBackgroundResource(R.drawable.background_main_menu);
Display display = getWindowManager().getDefaultDisplay();
//Point size = new Point();
//display.getSize(size);
fr.setBackgroundDrawable(new BitmapDrawable(getResources(), decodeSampledBitmapFromResource(getResources(), R.drawable.background_main_menu, 2000, 1250)));

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/mainmenu_background"
>

Answer 1

原因很简单，一个映像需要4x2000x1250字节的内存。每个像素都有一部分红、绿、蓝和阿尔法通道信息。

30 MB有点奇怪，但9MB是正常的:4x2000x1250=10000000字节->9.5MB

你确定你不偷看什么地方的记忆吗？