一手遮天 Android

项目地址 https://github.com/webabcd/AndroidDemo
作者 webabcd

一手遮天 Android - view（集合类）: ExpandableListView 基础

示例如下:

/view/collection/ExpandableListViewDemo1.java

/**
 * ExpandableListView - 可展开的 ListView
 *
 * ExpandableListView 的 Adapter 可以用 BaseExpandableListAdapter（最常用的）, SimpleExpandableListAdapter, SimpleCursorTreeAdapter
 * 关于 ExpandableListView 的知识点，请参见本程序的 MainActivity 中的代码
 */

package com.webabcd.androiddemo.view.collection;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

import com.webabcd.androiddemo.R;

public class ExpandableListViewDemo1 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_view_collection_expandablelistviewdemo1);
    }
}

/layout/activity_view_collection_expandablelistviewdemo1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

</LinearLayout>

/MainActivity.java

/**
 * 通过 ExpandableListView 做本程序的导航
 */

package com.webabcd.androiddemo;

import android.content.ComponentName;
import android.content.Intent;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import android.view.View;
import android.widget.ExpandableListView;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.webabcd.androiddemo.utils.Helper;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private ExpandableListView mExpandableListView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mExpandableListView = (ExpandableListView) findViewById(R.id.expandableListView);

        // 获取导航数据
        String jsonString = Helper.getAssetString("site_map.json", this);
        Type type = new TypeToken<List<MainNavigationBean>>() { }.getType();
        Gson gson = new Gson();
        final ArrayList<MainNavigationBean> navigationBeanList = gson.fromJson(jsonString, type);

        // 为 ExpandableListView 提供 Adapter
        final MainExpandableListAdapter adapter = new MainExpandableListAdapter(navigationBeanList);
        mExpandableListView.setAdapter(adapter);

        // 父的展开事件监听
        adapter.setOnGroupExpandedListener(new OnGroupExpandedListener() {
            @Override
            public void onGroupExpanded(int groupPosition) {
                // 每次展开一个分组后，关闭其他的分组
                int groupLength = mExpandableListView.getExpandableListAdapter().getGroupCount();
                for (int i = 0; i < groupLength; i++) {
                    if (i != groupPosition && mExpandableListView.isGroupExpanded(i)) {
                        mExpandableListView.collapseGroup(i);
                    }
                }
            }
        });

        // 父的点击事件监听
        mExpandableListView.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {
            @Override
            public boolean onGroupClick(ExpandableListView parent, View v, int groupPosition, long id) {
                // 要返回 false
                return false;
            }
        });

        // 子的点击事件监听
        mExpandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {
            @Override
            public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
                String className = "com.webabcd.androiddemo" + navigationBeanList.get(groupPosition).getNodeList().get(childPosition).getUrl();
                Intent intent = new Intent();
                ComponentName componentName = new ComponentName("com.webabcd.androiddemo", className);
                intent.setComponent(componentName);
                startActivity(intent);

                return true;
            }
        });
    }
}

/MainExpandableListAdapter.java

/**
 * 自定义 BaseExpandableListAdapter，用于为本程序首页的 ExpandableListView 提供数据和模板
 */

package com.webabcd.androiddemo;

import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

import java.util.List;

public class MainExpandableListAdapter extends BaseExpandableListAdapter {
    private final String LOG_TAG = "MainAdapter";

    private List<MainNavigationBean> mNavigationBeanList;
    private OnGroupExpandedListener mOnGroupExpandedListener;

    public MainExpandableListAdapter(List<MainNavigationBean> navigationBeanList) {
        mNavigationBeanList = navigationBeanList;
    }

    public void setOnGroupExpandedListener(OnGroupExpandedListener onGroupExpandedListener) {
        mOnGroupExpandedListener = onGroupExpandedListener;
    }

    @Override
    public int getGroupCount() {
        return mNavigationBeanList.size();
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return mNavigationBeanList.get(groupPosition).getNodeList().size();
    }

    @Override
    public Object getGroup(int groupPosition) {
        return mNavigationBeanList.get(groupPosition);
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return mNavigationBeanList.get(groupPosition).getNodeList().get(childPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return groupPosition;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return groupPosition * 10000 + childPosition;
    }

    @Override
    public boolean hasStableIds() {
        return true;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
        GroupViewHolder groupViewHolder;
        if (convertView == null) {
            convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_expand_group, parent, false);
            groupViewHolder = new GroupViewHolder();
            groupViewHolder.textViewTitle = (TextView) convertView.findViewById(R.id.textView1);
            convertView.setTag(groupViewHolder);
        } else {
            groupViewHolder = (GroupViewHolder) convertView.getTag();
        }

        groupViewHolder.textViewTitle.setText(mNavigationBeanList.get(groupPosition).getTitle());

        return convertView;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        ChildViewHolder childViewHolder;
        if (convertView == null) {
            convertView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_expand_child, parent, false);
            childViewHolder = new ChildViewHolder();
            childViewHolder.textViewTitle = (TextView) convertView.findViewById(R.id.textView1);
            convertView.setTag(childViewHolder);
        } else {
            childViewHolder = (ChildViewHolder) convertView.getTag();
        }

        childViewHolder.textViewTitle.setText(mNavigationBeanList.get(groupPosition).getNodeList().get(childPosition).getTitle());

        return convertView;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    @Override
    public void onGroupExpanded(int groupPosition) {
        Log.d(LOG_TAG, "onGroupExpanded() " + groupPosition);
        if (mOnGroupExpandedListener != null) {
            mOnGroupExpandedListener.onGroupExpanded(groupPosition);
        }
    }

    @Override
    public void onGroupCollapsed(int groupPosition) {
        Log.d(LOG_TAG, "onGroupCollapsed() " + groupPosition);
    }

    private static class GroupViewHolder {
        TextView textViewTitle;
    }

    private static class ChildViewHolder {
        TextView textViewTitle;
    }
}

/MainNavigationBean.java

/**
 * 本程序首页的 ExpandableListView 数据源的实体类
 */

package com.webabcd.androiddemo;

import com.google.gson.annotations.SerializedName;

import java.util.List;

public class MainNavigationBean {
    @SerializedName("title")
    private String mTitle; // 父节点 title
    @SerializedName("node")
    private List<NodeBean> mNodeList; // 子节点列表

    public String getTitle() {
        return mTitle;
    }

    public void setTitle(String title) {
        this.mTitle = title;
    }

    public List<NodeBean> getNodeList() {
        return mNodeList;
    }

    public void setNodeList(List<NodeBean> nodeList) {
        this.mNodeList = nodeList;
    }



    // 注：可以安装一个名为 GsonFormat 的插件（安装后可通过快捷键 alt + s 调出），其用于将 json 字符串解析为实体类
    public static class NodeBean {
        @SerializedName("title")
        private String mTitle; // 子节点 title
        @SerializedName("url")
        private String mUrl; // 子节点 url

        public String getTitle() {
            return mTitle;
        }

        public void setTitle(String title) {
            this.mTitle = title;
        }

        public String getUrl() {
            return mUrl;
        }

        public void setUrl(String url) {
            this.mUrl = url;
        }
    }
}

/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!--
        divider - 父分隔线（不需要的话可以设置为 @null）
        childDivider - 子分隔线（不需要的话可以设置为 @null）
        dividerHeight - 分隔线的高度（包括父和子）
        groupIndicator - 组图标（可以分别指定组收缩状态和组展开状态的图标）
    -->
    <ExpandableListView
        android:id="@+id/expandableListView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:divider="@color/orange"
        android:childDivider="@color/gray"
        android:dividerHeight="2dp"
        android:groupIndicator="@drawable/selector_expand_group"/>

</LinearLayout>

项目地址 https://github.com/webabcd/AndroidDemo
作者 webabcd