java - 全局布局监听器返回 0

Question

您好，我想通过全局布局监听器获取相对布局的高度和宽度:

final RelativeLayout relativeLayout = binding.rl;

      relativeLayout.getViewTreeObserver()
              .addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
           @Override
           public void onGlobalLayout() {
               // TODO Auto-generated method stub

                   width = relativeLayout.getWidth();
                   height = relativeLayout.getHeight();
                   relativeLayout.getViewTreeObserver()
                           .removeOnGlobalLayoutListener(this);

           }
       });

我的代码的问题是宽度和高度都为零。有人可以告诉我任何解决方案吗？提前致谢。

   <RelativeLayout
                                android:id="@+id/rl"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                               android:layout_marginTop="@dimen/dp12">

  <androidx.recyclerview.widget.RecyclerView
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
                                    />
    </RelativeLayout>

Answer 1

如果您没有其他选择，请尝试使用 getMeasuredWidth() 或 getMeasuredHeight() :

relativeLayout.measure(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
int width = relativeLayout.getMeasuredWidth();
int height = relativeLayout.getMeasuredHeight();

但是根据你的问题，仅当高度或重量大于0时才尝试删除OnGlobalLayoutListener，因为如果你的布局宽度/高度是“wrap_content”，它实际上可能是0:

    relativeLayout.getViewTreeObserver()
            .addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {
                    // TODO Auto-generated method stub

                    width = relativeLayout.getWidth();
                    height = relativeLayout.getHeight();

                    if (width > 0) {
                        relativeLayout.getViewTreeObserver()
                                .removeOnGlobalLayoutListener(this);
                    }
                }
            });