如何在OpenHarmony中使用ListView组件进行列表筛选

在OpenHarmony（开放鸿蒙）中，使用ListView组件进行列表筛选通常涉及以下几个步骤：

1. 创建ListView组件

首先，你需要在你的应用中创建一个ListView组件。

<!-- example.xml -->
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:orientation="vertical">

    <ListView
        ohos:id="$+id:list_view"
        ohos:height="match_parent"
        ohos:width="match_parent" />
</DirectionalLayout>

2. 准备数据源

准备一个包含所有数据的列表。

// ExampleData.java
public class ExampleData {
    private String name;
    private int age;

    public ExampleData(String name, int age) {
        this.name = name;
        this.age = age;
    }

    // Getters and setters
}

3. 创建适配器

创建一个适配器来绑定数据到ListView。

// ExampleAdapter.java
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Component;
import ohos.agp.components.ListContainer;
import ohos.agp.components.ListItem;
import ohos.agp.components.LayoutScatter;
import ohos.agp.components.Text;
import ohos.data.DataProvider;
import ohos.data.ListDataProvider;

import java.util.ArrayList;
import java.util.List;

public class ExampleAdapter extends ListDataProvider {
    private List<ExampleData> dataList;

    public ExampleAdapter(List<ExampleData> dataList) {
        this.dataList = dataList;
    }

    @Override
    public int getCount() {
        return dataList.size();
    }

    @Override
    public Object getItem(int position) {
        return dataList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public Component getComponent(int position, Component convertComponent, ComponentContainer parent) {
        if (convertComponent == null || !(convertComponent instanceof ListItem)) {
            convertComponent = LayoutScatter.getInstance(getContext()).parse(ResourceTable.Layout_item_layout, parent, false);
        }
        ListItem listItem = (ListItem) convertComponent;
        ExampleData data = (ExampleData) getItem(position);
        Text nameText = listItem.findComponentById(ResourceTable.Id_name);
        Text ageText = listItem.findComponentById(ResourceTable.Id_age);
        nameText.setText(data.getName());
        ageText.setText(String.valueOf(data.getAge()));
        return listItem;
    }
}

4. 实现筛选逻辑

在AbilitySlice中实现筛选逻辑，并更新适配器的数据源。

// ExampleAbilitySlice.java
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Component;
import ohos.agp.components.ListContainer;
import ohos.agp.components.Text;
import ohos.data.DataProvider;
import ohos.data.ListDataProvider;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

public class ExampleAbilitySlice extends AbilitySlice {
    private ListView listView;
    private ExampleAdapter adapter;
    private List<ExampleData> originalDataList;
    private List<ExampleData> filteredDataList;

    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_example);

        listView = (ListView) findComponentById(ResourceTable.Id_list_view);
        originalDataList = new ArrayList<>();
        // 添加一些示例数据
        originalDataList.add(new ExampleData("Alice", 25));
        originalDataList.add(new ExampleData("Bob", 30));
        originalDataList.add(new ExampleData("Charlie", 35));

        filteredDataList = new ArrayList<>(originalDataList);
        adapter = new ExampleAdapter(filteredDataList);
        listView.setDataProvider(adapter);

        // 添加筛选按钮
        Text filterButton = (Text) findComponentById(ResourceTable.Id_filter_button);
        filterButton.setClickedListener(component -> {
            String filterText = ((Text) component).getText();
            filteredDataList = originalDataList.stream()
                    .filter(data -> data.getName().toLowerCase().contains(filterText.toLowerCase()))
                    .collect(Collectors.toList());
            adapter.updateData(filteredDataList);
        });
    }
}

5. 布局文件

确保你的布局文件中包含ListView和筛选按钮。

<!-- example.xml -->
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:orientation="vertical">

    <Text
        ohos:id="$+id/filter_button"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:text="Filter"
        ohos:gravity="center" />

    <ListView
        ohos:id="$+id/list_view"
        ohos:height="match_parent"
        ohos:width="match_parent" />
</DirectionalLayout>

6. 布局项布局

确保你有一个布局文件用于显示列表项。

<!-- item_layout.xml -->
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_content"
    ohos:width="match_parent"
    ohos:orientation="horizontal">

    <Text
        ohos:id="$+id_name"
        ohos:height="match_content"
        ohos:width="match_parent"
        ohos:text="Name"
        ohos:gravity="center_vertical" />

    <Text
        ohos:id="$+id_age"
        ohos:height="match_content"
        ohos:width="match_parent"
        ohos:text="Age"
        ohos:gravity="center_vertical" />
</DirectionalLayout>

通过以上步骤，你可以在OpenHarmony中使用ListView组件进行列表筛选。