Android - 测量视图后更新位图

Question

我正在尝试从图像视图中检索位图，然后对其进行缩放。但我收到以下错误：

"java.lang.IllegalArgumentException: width and height must be > 0"

我在网上搜索是因为在 imageView 完成测量并转换为位图之前，我尝试更新位图。任何人都可以帮我解决这个问题。我的代码如下：

profileImage.buildDrawingCache();
Bitmap bm = profileImage.getDrawingCache();

int widthPixel = bm.getWidth();
int heightPixel = bm.getHeight();
int basePixel;
float widthRatio;
float heightRatio;

if (widthPixel < heightPixel) {
  basePixel = widthPixel;
}
else {
   basePixel = heightPixel;
}

if (basePixel > 180) {
  widthRatio = 180/basePixel;
  heightRatio = 180/basePixel;
}
else {
   widthRatio = 1;
   heightRatio = 1;
}

Bitmap bmResized = Bitmap.createScaledBitmap(bm,(int)(bm.getWidth()*widthRatio), (int)(bm.getHeight()*heightRatio), true);
// bm.recycle();

ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmResized.compress(Bitmap.CompressFormat.JPEG, 100, stream);
byteArray1 = stream.toByteArray();

编辑后的代码（现在出现“java.lang.IllegalArgumentException: value may not be null.”错误）：

                                    profileImage.buildDrawingCache();
                                    bm = profileImage.getDrawingCache();



                                    profileImage.getViewTreeObserver().addOnPreDrawListener(new OnPreDrawListener() {
                                        public boolean onPreDraw() {
                                            profileImage.getViewTreeObserver().removeOnPreDrawListener(this);

                                            widthPixel = profileImage.getMeasuredWidth();
                                            heightPixel = profileImage.getMeasuredHeight();

                                            if (widthPixel < heightPixel) {

                                                basePixel = widthPixel;

                                            }

                                            else {

                                                basePixel = heightPixel;

                                            }


                                            if (basePixel > 180) {

                                                widthRatio = 180/basePixel;
                                                heightRatio = 180/basePixel;


                                            }

                                            else {

                                                widthRatio = 1;
                                                heightRatio = 1;

                                            }


                                            Bitmap bmResized = Bitmap.createScaledBitmap(bm,(int)(bm.getWidth()*widthRatio), (int)(bm.getHeight()*heightRatio), true);
                                            // bm.recycle();

                                            ByteArrayOutputStream stream = new ByteArrayOutputStream();
                                            bmResized.compress(Bitmap.CompressFormat.JPEG, 100, stream);
                                            byteArray1 = stream.toByteArray();

                                            image1 = new ParseFile("profilePhoto.jpg", byteArray1, "image/jpg");

                                            return true;
                                        }
                                    });

Answer 1

使用OnPreDrawListener。 OnPreDrawListener 允许您在 View 的度量操作之后但在布局阶段之前检索您的 View 维度。这意味着这是您可以获取视图尺寸的最早时间。

view.getViewTreeObserver().adOnPreDrawListener(new OnPreDrawListener() {
    public boolean onPreDraw() {
        view.getViewTreeObserver().removeOnPreDrawListener(this);


        int width = view.getMeasuredWidth();
        int height = view.getMeasuredHeight();

        // TODO scale your bitmap here

        return true;
    }
});