工具篇——ExpandableListViewForScrollView（解决ScrollView嵌套ExpandableListView，ExpandableListView显示不全的问题）

 

写代码的四点：

     1.明确需求。要做什么？

     2.分析思路。要怎么做？（1,2,3……）

     3.确定步骤。每一个思路要用到哪些语句、方法和对象。

     4.代码实现。用具体的语言代码将思路实现出来。

 

学习新技术的四点：

     1.该技术是什么？

     2.该技术有什么特点？（使用需注意的方面）

     3.该技术怎么使用？（写Demo）

     4.该技术什么时候用？（在Project中的使用场景 ）

 

----------------------早计划，早准备，早完成。-------------------------

代码如下：

 

package com.gzqol.fjsharedlibrary.customview;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ExpandableListView;
import android.widget.ListView;

/**
 * 解决ScrollView嵌套ExpandableListView，ExpandableListView显示不全的问题
 * 注意：ScrollView嵌套ExpandableListView时，ExpandableListView很长超出了屏幕的高度，那么ScrollView会自动滚动到底部，
 * 但是我们需要默认在顶部，所以在初始化的时候就让ScrollView获得焦点，滚动条自然就显示到顶部了。
 * scrollView.setFocusable(true);
 * scrollView.setFocusableInTouchMode(true);
 * scrollView.requestFocus();
 */
public class ExpandableListViewForScrollView extends ExpandableListView {

    public ExpandableListViewForScrollView(Context context) {
        super(context);
    }

    public ExpandableListViewForScrollView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public ExpandableListViewForScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    /**
     * 重写onMeasure方法，重新计算高度，达到使ExpandableListView适应ScrollView的效果
     *
     * @param widthMeasureSpec  宽度测量规则
     * @param heightMeasureSpec 高度测量规则
     */
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        //Integer.MAX_VALUE:表示int类型能够表示的最大值，值为2的31次方-1
        //>>2:右移N位相当于除以2的N的幂
        //MeasureSpec.AT_MOST：子布局可以根据自己的大小选择任意大小的模式
        int newHeightMeasureSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, newHeightMeasureSpec);
    }
}

 

 

 

在项目中的应用：

1.在xml布局文件中直接使用；

 

2.注意：ScrollView嵌套ExpandableListViewForScrollView时，

             如果ExpandableListViewForScrollView很长超出了屏幕的高度，

             那么ScrollView会自动滚动到ExpandableListViewForScrollView的顶部，

             但是我们需要默认在整体页面顶部，所以在初始化的时候就让ScrollView获得焦点，

             滚动条自然就显示到顶部了。

scrollView.setFocusable(true);
scrollView.setFocusableInTouchMode(true);
scrollView.requestFocus();

3.创建adapter处理数据及逻辑

 

/**
 * 初始化listview
 */
private void initListView() {
    BorrowQueryBrowseAdapter borrowQueryBrowseAdapter = new BorrowQueryBrowseAdapter(context);
    elv.setAdapter(borrowQueryBrowseAdapter);

    //展开所有组
    for (int i = 0; i < borrowQueryBrowseAdapter.getGroupCount(); i++) {
        elv.expandGroup(i);
    }

    //组点击无效果
    elv.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {

        @Override
        public boolean onGroupClick(ExpandableListView parent, View v,
                                    int groupPosition, long id) {
            return true;
        }
    });
}

3.1数据适配器adapter的代码

 

package com.gzqol.fjsharedlibrary.adapter;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.gzqol.fjsharedlibrary.R;

import butterknife.ButterKnife;
import butterknife.InjectView;

/**
 */
public class BorrowQueryBrowseAdapter extends BaseExpandableListAdapter {
    private final Context context;

    public BorrowQueryBrowseAdapter(Context context) {
        this.context = context;
    }

    @Override
    public int getGroupCount() {
        return 5;
    }

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

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

    @Override
    public View getGroupView(final int groupPosition, final boolean isExpanded, View convertView, ViewGroup parent) {
        GroupViewHolder groupViewHolder;
        if (convertView == null) {
            convertView = View.inflate(context, R.layout.item_borrow_query_browse_group, null);

            groupViewHolder = new GroupViewHolder(convertView);
            convertView.setTag(groupViewHolder);
        } else {
            groupViewHolder = (GroupViewHolder) convertView.getTag();
        }

        if (groupPosition == 0){
            groupViewHolder.viewFirst.setVisibility(View.GONE);
        }else {
            groupViewHolder.viewFirst.setVisibility(View.VISIBLE);
        }

        return convertView;
    }

    static class GroupViewHolder {
        @InjectView(R.id.view_first)
        View viewFirst;
        @InjectView(R.id.tv_jieshudanhao)
        TextView tvJieshudanhao;
        @InjectView(R.id.tv_zongceshu)
        TextView tvZongceshu;
        @InjectView(R.id.tv_zongmayang)
        TextView tvZongmayang;

        GroupViewHolder(View view) {
            ButterKnife.inject(this, view);
        }
    }

    //------------------------------------------------------------------------------------------------
    @Override
    public int getChildrenCount(int groupPosition) {
        return 2;
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return childPosition;
    }

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

    @Override
    public View getChildView(final int groupPosition, final int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
        ChildViewHolder childViewHolder;
        if (convertView == null) {
            convertView = View.inflate(context, R.layout.item_borrow_query_browse_child, null);

            childViewHolder = new ChildViewHolder(convertView);
            convertView.setTag(childViewHolder);
        } else {
            childViewHolder = (ChildViewHolder) convertView.getTag();
        }

        if (childPosition == 1){
            childViewHolder.viewLast.setVisibility(View.GONE);
        }else {
            childViewHolder.viewLast.setVisibility(View.VISIBLE);
        }
        return convertView;
    }

    static class ChildViewHolder {
        @InjectView(R.id.iv_photo)
        ImageView ivPhoto;
        @InjectView(R.id.tv_title)
        TextView tvTitle;
        @InjectView(R.id.tv_author)
        TextView tvAuthor;
        @InjectView(R.id.tv_price)
        TextView tvPrice;
        @InjectView(R.id.tv_jiechushijian)
        TextView tvJiechushijian;
        @InjectView(R.id.tv_yinghuanshijian)
        TextView tvYinghuanshijian;
        @InjectView(R.id.tv_jieshumendian)
        TextView tvJieshumendian;
        @InjectView(R.id.tv_number)
        TextView tvNumber;
        @InjectView(R.id.view_last)
        View viewLast;

        ChildViewHolder(View view) {
            ButterKnife.inject(this, view);
        }
    }

    //-----------------------------------------------------------------------------------------------

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

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

附：

详细使用Demo（https://blog.csdn.net/qq941263013/article/details/80901277）

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简书：https://www.jianshu.com/u/e5e733d79b96