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HarmonyOS ListContainer 实现列表

编程日记 2024/03/15 18:14:16

先看下实现的效果如下:

HarmonyOS ListContainer 实现列表配图01

ListContainer 是用来实现列表的

学习ListContainer 这个属性看实现的源码是少不了的,

在里面看到setItemProvider 应该是用来记载item的

HarmonyOS ListContainer 实现列表配图02

它里面是 BaseItemProvider 在跳进去看看

这个里面有获取item ,以及布局,刷新等,(不过我看的第一次看到getCount,getItem,getItemId,还以为是andriod的viewpage呢,开个玩笑,这里大致能想到,继承这个抽象类的时候,会生成四个方法,getComponent 是加载list的item布局的,getItem是用来获取item内容的,)

HarmonyOS ListContainer 实现列表配图03

看到这,我们要想使用setItemProvider 就要创建一个类来继承这个抽象的BaseItemProvider

明白了大致的思路下面开始,

首先在主界面的xml中写一个ListContainer 具体如下:

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayoutxmlns:ohos="http://schemas.huawei.com/res/ohos"ohos:height="match_parent"ohos:width="match_parent"ohos:orientation="vertical"><ListContainerohos:id="$+id:list"ohos:height="match_parent"ohos:width="match_parent"/></DirectionalLayout>

我这里创建了一个 BaseProvider 来继承 BaseItemProvider

HarmonyOS ListContainer 实现列表配图04

生成之后就是往里面添加内容了,具体的如下,

package com.example.myapplication.slice;import com.example.myapplication.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.agp.components.BaseItemProvider;
import ohos.agp.components.Component;
import ohos.agp.components.ComponentContainer;
import ohos.agp.components.LayoutScatter;import java.util.List;public class BaseProvider extends BaseItemProvider {// 定义一个listprivate List<String> list;// 定义一个上下文private AbilitySlice content;public BaseProvider(List<String> list,AbilitySlice content) {super();this.list = list;this.content = content;}@Overridepublic int getCount() {return list == null ? 0 : list.size();}@Overridepublic Object getItem(int i) {return list.get(i);}@Overridepublic long getItemId(int i) {return i;}@Overridepublic Component getComponent(int i, Component component, ComponentContainer componentContainer) {component = LayoutScatter.getInstance(content).parse(ResourceTable.Layout_item_sample, null, false);return component;}
}

这里插入的一个item的如下

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayoutxmlns:ohos="http://schemas.huawei.com/res/ohos"ohos:height="match_content"ohos:width="match_parent"ohos:orientation="vertical"><Textohos:id="$+id:item"ohos:height="60fp"ohos:width="match_content"ohos:text="HarmonyOS"ohos:layout_alignment="center"ohos:text_size="20fp"/><Textohos:height="1fp"ohos:width="match_parent"ohos:background_element="#00d8a0"/>
</DirectionalLayout>

写好之后就去java里面去试试

下面先写100个数据看看

package com.example.myapplication.slice;import com.example.myapplication.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Component;
import ohos.agp.components.ListContainer;
import ohos.agp.window.dialog.ToastDialog;import java.util.ArrayList;
import java.util.List;public class MainAbilitySlice extends AbilitySlice {private ListContainer listContainer;@Overridepublic void onStart(Intent intent) {super.onStart(intent);super.setUIContent(ResourceTable.Layout_main_layout);listContainer = (ListContainer) findComponentById(ResourceTable.Id_list);List<String> list = new ArrayList<>();for (int i = 0; i < 100; i++) {list.add("");}BaseProvider baseProvider = new BaseProvider(list, this);listContainer.setItemProvider(baseProvider);listContainer.setItemClickedListener(new ListContainer.ItemClickedListener() {@Overridepublic void onItemClicked(ListContainer listContainer, Component component, int i, long l) {new ToastDialog(getContext()).setText("点击了第" + i  + "个").show();}});}@Overridepublic void onActive() {super.onActive();}@Overridepublic void onForeground(Intent intent) {super.onForeground(intent);}
}

今天写实现一个简单的list ,list里面的要学习的内容挺多的,后续在更新一些,添加item 和删除item

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