什么是DirectionalLayout DirectionalLayout又称方向布局,是鸿蒙开发中几个常用的布局之一,使用频率较高,而且非常简单.布局内的控件依次排列,支持横向或纵向排列. 基础样例1. 纵向排列效果图代码 <?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos"; ohos:height="match_parent" ohos:width="match_parent" ohos:orientation="vertical"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程1"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程2"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程3"/></DirectionalLayout> 代码说明:

1. 设置ohos:orientation为vertical,展示方向变成纵向
2. DirectionalLayout里面包括了三个显示文本的Text.

2. 横向排列效果图代码 <?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos"; ohos:height="match_parent" ohos:width="match_parent" ohos:orientation="horizontal"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程1"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程2"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程3"/></DirectionalLayout> 代码说明:

1. 设置ohos:orientation为horizontal,展示方向变成横向.

3. 调整子控件摆放位置(gravity属性) 通过DirectionalLayout的ohos:alignment属性控制其子控件相对于自己的对齐方式. 3.1 水平居中效果图代码 <?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos"; ohos:height="match_parent" ohos:width="match_parent" ohos:alignment="horizontal_center"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程-水平居中"/></DirectionalLayout>3.2 垂直居中效果图 [外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-y0eZrvJ6-1634824230834)(https://upload-images.jianshu.io/upload_images/6169789-11bb955a945217ce.png?imageMogr2/auto-orient/strip|imageView2/2/w/1240)] 代码 <?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos"; ohos:height="match_parent" ohos:width="match_parent" ohos:alignment="vertical_center"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程-垂直居中"/></DirectionalLayout>3.3 水平 垂直居中效果图代码 <?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos"; ohos:height="match_parent" ohos:width="match_parent" ohos:alignment="center"> <Text ohos:height="match_content" ohos:width="match_content" ohos:text="花生皮编程-居中"/></DirectionalLayout>4. 按比例分空间(layout_weight) DirectionalLayout里的子控件可以通过weight属性按比例分空间大小(横向或纵向).按照DirectionalLayout里所有直属子控件(不算子控件的子控件)设置的weight作为总和,各个控件按照自己的weight所占总和比例来分空闲空间(有些控件未设置weight,则按照固定值). 4.1 等分空间效果图代码 <?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos"; ohos:height="match_parent" ohos:width="match_parent" ohos:orientation="horizontal"> <Text ohos:height="match_content" ohos:width="match_content" ohos:background_element="#f2eada" ohos:text="Text1" ohos:text_alignment="center" ohos:weight="1"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:background_element="#9b95c9" ohos:text="Text2" ohos:text_alignment="center" ohos:weight="1"/></DirectionalLayout> 代码说明:
1.两个按钮都设置ohos:weight属性,且值相同,故平分空间. 4.2 按比例分 一个控件保持固定大小,一个占据剩余可用空间. 效果图代码 <?xml version="1.0" encoding="utf-8"?><DirectionalLayout xmlns:ohos="http://schemas.huawei.com/res/ohos"; ohos:height="match_parent" ohos:width="match_parent" ohos:orientation="horizontal"> <Text ohos:height="match_content" ohos:width="match_content" ohos:background_element="#f2eada" ohos:text="Text1" ohos:text_alignment="center"/> <Text ohos:height="match_content" ohos:width="match_content" ohos:background_element="#9b95c9" ohos:text="Text2" ohos:text_alignment="center" ohos:weight="1"/></DirectionalLayout> 代码说明:

1. 第一个按钮不设置ohos:weight属性,保持本身大小.
2. 第二个按钮设置ohos:weight属性,占据所有剩余可用空间.

完整源代码 https://gitee.com/hspbc/harmonyos_demos/tree/master/directionalLayoutDemo 常用属性说明

属性名	用途
ohos:width	设置控件宽度,可设置为:match_parent(和父控件一样),match_content(按照内容自动伸缩),设置固定值(如200vp)
ohos:height	设置控件高度,可设置为:match_parent(和父控件一样),match_content(按照内容自动伸缩),设置固定值(如200vp)
ohos:layout_alignment	在父控件内对齐方式,可选值：left：居左；start：居左；center：居中；right：居右；end：居右；top：居上；bottom：居下；horizontal_center：水平居中；vertical_center：垂直居中
ohos:background_element	设置背景,可以是色值(如#FF0000)或图片等
ohos:visibility	可选值: visible(显示), invisible(隐藏,但是仍占据UI空间),hide(隐藏,且不占UI空间)
ohos:orientation	子控件排列方向，可选值，horizontal：横向；vertical：纵向
weight	DirectionalLayout所有直属子控件,通过该属性值按比例分剩余可用空间