鸿蒙应用开发- TabList和Tab

准备TabList页面布局

在layout目录下创建TabList布局，将其命名为ability_tablist.xml。

<?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">
    <TabList
        ohos:id="$+id:tab_list"
        ohos:background_element="#FFFF7F"
        ohos:top_margin="10vp"
        ohos:tab_margin="24vp"
        ohos:tab_length="140vp"
        ohos:text_size="20fp"
        ohos:height="36vp"
        ohos:width="match_parent"
        ohos:layout_alignment="center"
        ohos:orientation="horizontal"
        ohos:text_alignment="center"
        ohos:normal_text_color="#999999"
        ohos:selected_text_color="#000000"
        ohos:selected_tab_indicator_color="#000000"
        ohos:selected_tab_indicator_height="2vp"/>
    <DirectionalLayout
        ohos:id="$+id:tab_container"
        ohos:height="match_parent"
        ohos:width="match_parent">
    </DirectionalLayout>
</DirectionalLayout>

布局代码中第7行~第22行的用于生成TabList组件，定义了TabList的基本属性；第23行~第27行用于生成Tab页面的容器，目前还没有具体内容，稍后有具体代码生成。

准备Image页面

Image页面主要包含一个Image文件和简单的文字表示：

<?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">
    <Component
        ohos:height="0vp"
        ohos:weight="3"
        ohos:width="match_parent"
    />
    <DirectionalLayout
        xmlns:ohos="http://schemas.huawei.com/res/ohos"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:layout_alignment="center"
        ohos:orientation="vertical">
        <Image
            ohos:id="$+id:image"
            ohos:width="match_content"
            ohos:height="match_content"
            ohos:layout_alignment="center"
            ohos:image_src="$media:DevEco"
        />
        <Component
            ohos:height="20vp"
            ohos:width="match_parent"
            />
        <Text
            ohos:id="$+id:text_helloworld"
            ohos:height="match_content"
            ohos:width="match_content"
            ohos:layout_alignment="horizontal_center"
            ohos:text="Image Tab"
            ohos:text_color="#007F00"
            ohos:text_size="100"
        />
    </DirectionalLayout>
    <Component
        ohos:height="0vp"
        ohos:weight="5"
        ohos:width="match_parent"
        />
</DirectionalLayout>

准备Video页面

Video页面包含一个动画，稍微复杂一些。首先是页面本身：

<?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">
    <Component
        ohos:height="0vp"
        ohos:weight="3"
        ohos:width="match_parent"
    />
    <DirectionalLayout
        xmlns:ohos="http://schemas.huawei.com/res/ohos"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:layout_alignment="center"
        ohos:orientation="vertical">
        <Component
            ohos:id="$+id:video_area"
            ohos:height="300vp"
            ohos:width="300vp"
            />
        <Component
            ohos:height="20vp"
            ohos:width="match_parent"
            />
        <Text
            ohos:id="$+id:text_helloworld"
            ohos:height="match_content"
            ohos:width="match_content"
            ohos:layout_alignment="horizontal_center"
            ohos:text="Video Tab"
            ohos:text_color="#0000FF"
            ohos:text_size="100"
        />
    </DirectionalLayout>
    <Component
        ohos:height="0vp"
        ohos:weight="5"
        ohos:width="match_parent"
        />
</DirectionalLayout>

这个文件和Image页面区别不大，只是在用Component组件代替了Image组件。而动画的实际内容则是由graphic目录中的animation_element.xml文件决定：

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:ohos="http://schemas.huawei.com/res/ohos"
                ohos:oneshot="false">
    <item ohos:element="$media:video01" ohos:duration="100"/>
    <item ohos:element="$media:video02" ohos:duration="100"/>
    <item ohos:element="$media:video03" ohos:duration="100"/>
    <item ohos:element="$media:video04" ohos:duration="100"/>
    <item ohos:element="$media:video05" ohos:duration="100"/>
    <item ohos:element="$media:video06" ohos:duration="100"/>
    <item ohos:element="$media:video07" ohos:duration="100"/>
    <item ohos:element="$media:video08" ohos:duration="100"/>
    <item ohos:element="$media:video09" ohos:duration="100"/>
    <item ohos:element="$media:video10" ohos:duration="100"/>
    <item ohos:element="$media:video11" ohos:duration="100"/>
</animation-list>

生成TabList画面

TabList的每个Tab页面需要由代码生成，具体参见下面的页面类：

package com.example.helloharmony.slice;

import com.example.helloharmony.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.*;
import ohos.agp.components.element.FrameAnimationElement;

import java.io.Console;

public class TablistAbilitySlice extends AbilitySlice {
    private Component imageContent;
    private Component videoContent;
    private FrameAnimationElement frameAnimationElement;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_tablist);
        TabList tabList = (TabList) findComponentById(ResourceTable.Id_tab_list);
        tabList.setTabLength(200); // 设置Tab的宽度
        tabList.setTabMargin(26); // 设置两个Tab之间的间距
        TabList.Tab tab1 = tabList.new Tab(getContext());
        tab1.setText("Image");
        tabList.addTab(tab1);
        TabList.Tab tab2 = tabList.new Tab(getContext());
        tab2.setText("Video");
        tabList.addTab(tab2);
        AbilitySlice slice = this;
        tabList.addTabSelectedListener(new TabList.TabSelectedListener() {
            @Override
            public void onSelected(TabList.Tab tab) {
                ComponentContainer container = (ComponentContainer) findComponentById(ResourceTable.Id_tab_container);
                if(tab.getText().equals("Image")) {
                    imageContent = LayoutScatter.getInstance(slice).parse(ResourceTable.Layout_iamge_tab, null, false);
                    container.addComponent(imageContent);
                }
                else
                {
                    videoContent = LayoutScatter.getInstance(slice).parse(ResourceTable.Layout_video_tab, null, false);
                    frameAnimationElement = new FrameAnimationElement(slice.getContext(), ResourceTable.Graphic_animation_element);
                    Component videoArea = videoContent.findComponentById(ResourceTable.Id_video_area);
                    videoArea.setBackground(frameAnimationElement);
                    frameAnimationElement.start();
                    container.addComponent(videoContent);
                }
            }

            @Override
            public void onUnselected(TabList.Tab tab) {
                if(tab.getText().equals("Video")) {
                    frameAnimationElement.start();
                }
                ComponentContainer container = (ComponentContainer) findComponentById(ResourceTable.Id_tab_container);
                container.removeAllComponents();
            }

            @Override
            public void onReselected(TabList.Tab tab) {
                ComponentContainer container = (ComponentContainer) findComponentById(ResourceTable.Id_tab_container);
                if(tab.getText().equals("Image")) {
                    container.addComponent(imageContent);
                }
                else
                {
                    frameAnimationElement.start();
                    container.addComponent(videoContent);
                }
            }
        });
        //最开始选选择tab1
        tabList.selectTab(tab1);
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}

代码第22行~第27行分别生成了Image和Video两个Tab页。

第29行~第69行是为TabList的各种事件提供响应。需要响应的处理主要有Tab页选择，Tab页取消选择和Tab重新选择。代码中根据当前选中的Tab页面生成或选择不同的组件。

参考文档:

TabList和Tab组件

https://developer.harmonyos.com/cn/docs/documentation/doc-guides/ui-java-component-tablist-tab-0000001062229749

TabList类

https://developer.harmonyos.com/cn/docs/documentation/doc-references/tablist-0000001054238721

Tab List.Tab类

https://developer.harmonyos.com/cn/docs/documentation/doc-references/tablist_tab-0000001054678691

动画开发指导

https://developer.harmonyos.com/cn/docs/documentation/doc-guides/ui-java-animation-0000000000580278