java - 如何减少在android中内存上滑动加载的图像大小

Question

我正在尝试使用glide从互联网加载图像，但该图像对于我的应用程序来说太大了(图像尺寸为400X400，内存分配为352KB，ImageView的大小与图像尺寸相同) ),我尝试在加载位图后对其进行解码，然后将其应用到 ImageView 但它不起作用，任何人都可以帮助我解决这个问题。

这是我的 Glide 代码:

Glide.with(this)
                .asBitmap()
                .load(url)
                .into(new SimpleTarget<Bitmap>() {
                    @Override
                    public void onResourceReady(@NonNull Bitmap resource, @Nullable Transition<? super Bitmap> transition) {
                        int byteCount = resource.getAllocationByteCount();

                        int sizeInKB = (resource.getRowBytes() * resource.getHeight()) / 1024;
                        int sizeInMB = sizeInKB / 1024;

                        Glide.with(TestActivity.this)
                                .asBitmap()
                                .load(decodeSampledBitmapFromResource(resource, 400, 400))
                                .into(ss2);

                        sizeText.setText(sizeInKB + " KB");
                    }
                });

这是解码位图的代码:

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) {

        final int halfHeight = height / 2;
        final int halfWidth = width / 2;

        // Calculate the largest inSampleSize value that is a power of 2 and keeps both
        // height and width larger than the requested height and width.
        while ((halfHeight / inSampleSize) >= reqHeight
                && (halfWidth / inSampleSize) >= reqWidth) {
            inSampleSize *= 2;
        }
    }

    return inSampleSize;
}

public static Bitmap decodeSampledBitmapFromResource(Bitmap bitmap, int reqWidth, int reqHeight) {

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

    ByteArrayOutputStream blob = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 0, blob);
    byte[] bitmapData = blob.toByteArray();
    BitmapFactory.decodeByteArray(bitmapData, 0, bitmapData.length, options);

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

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;

    bitmap.compress(Bitmap.CompressFormat.PNG, 0, blob);
    byte[] bitmapData2 = blob.toByteArray();
    return BitmapFactory.decodeByteArray(bitmapData2, 0, bitmapData2.length, options);
}

Answer 1

图像的大小取决于很多因素，其中之一是尺寸和质量；默认情况下，Glide V4 中的质量格式是 ARGB_8888，因此如果您使用它，可以将其更改为更小的 RGB_565。您可以找到此信息以及更多信息 here .