布局文件提示错误“No orientation specified, and the default is horizontal. This is a common so...”

完整的错误提示信息为：No orientation specified, and the default is horizontal. This is a common source of bugs when

children are added dynamically.

通常发生这个错误提示的原因是我们直接在原有的页面上把别的布局标签改成<LinearLayout>，可是使用<LinearLayout>标签要指明方向，水平方向还是垂直方向

horizontal or vertical

所以直接改动，会导致没有指名线性布局的方向，仅仅要加入上

android:orientation = "vertical"

或

android:orientation = "horizontal"

就可以解决

布局文件提示错误“No orientation specified, and the default is horizontal. This is a common so...”