自己的View工具类---ViewUtil

最新推荐文章于 2020-07-20 10:40:54 发布

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本文介绍了一种用于动态调整Android中ListView及其子类ExpandableListView高度的方法。通过计算子项的总高度来实现ListView自适应布局的需求，并提供了处理ListView展开与收起时高度变化的解决方案。

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package com.app.util;

import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ListAdapter;
import android.widget.ListView;

/**
 * 解决view高度之类的问题
 * @author Wonghoman
 */
public class ViewUtil {
	
	private final String TAG = "ViewUtil";
	
	/** 
	 * 动态改变listView的高度 
	 * 计算ExpandableListView的group项的高度的方法（即计算listview合并时的高度的方法）
	 * 备注：ExpandableListView是listview的子类所以，listview的方法它同样可以使用
	 * 
	 * maxHeight：最大高度，不作限制的话用“非正数”表示
	 */
	public static void setListViewHeightBasedOnChildren(ListView listView, int maxHeight) {  
        // 获取ListView对应的Adapter  
        ListAdapter listAdapter = listView.getAdapter();  
        if(listAdapter == null) {  
            return;  
        }  
        int totalHeight = 0;  
        for(int i = 0, len = listAdapter.getCount(); i < len; i++) {
            View listItem = listAdapter.getView(i, null, listView);
            if(listItem == null)
            	return;
            listItem.measure(0, 0); // 计算子项View 的宽高  
            totalHeight += listItem.getMeasuredHeight(); // 统计所有子项的总高度  
        }  
        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = totalHeight  
                + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
        // listView.getDividerHeight()获取子项间分隔符占用的高度  
        if(maxHeight > 0){
        	params.height = params.height > maxHeight ? maxHeight : params.height;
        }
        listView.setLayoutParams(params);
    }
	
	/**
     * 可扩展listview展开时调用
     * 计算ExpandableListView展开时group下的子view列表的高度的方法
     * @param listView
     * @param groupPosition
     */
    public static void setExpandedListViewHeightBasedOnChildren(
            ExpandableListView listView, int groupPosition) {
        ExpandableListAdapter listAdapter = listView.getExpandableListAdapter();
        if (listAdapter == null) {
            return;
        }
        View listItem = listAdapter.getChildView(groupPosition, 0, true, null,
                listView);
        listItem.measure(0, 0);
        int appendHeight = 0;
        for (int i = 0; i < listAdapter.getChildrenCount(groupPosition); i++) {
            appendHeight += listItem.getMeasuredHeight();
        }
        ViewGroup.LayoutParams params = listView.getLayoutParams();
//        Log.d(TAG, "Expand params.height" + params.height);
        params.height += appendHeight;
        listView.setLayoutParams(params);
    }
    
    /**
     * 可扩展listview收起时调用
     * 计算ExpandableListView合并时消除group下的子view列表的高度的方法
     * @param listView
     * @param groupPosition
     */
    public static void setCollapseListViewHeightBasedOnChildren(
            ExpandableListView listView, int groupPosition) {
        ExpandableListAdapter listAdapter = listView.getExpandableListAdapter();
        if (listAdapter == null) {
            return;
        }
        View listItem = listAdapter.getChildView(groupPosition, 0, true, null,
                listView);
        listItem.measure(0, 0);
        int appendHeight = 0;
        for (int i = 0; i < listAdapter.getChildrenCount(groupPosition); i++) {
            appendHeight += listItem.getMeasuredHeight();
        }
        /*Log.d(TAG,
                "Collapse childCount="
                        + listAdapter.getChildrenCount(groupPosition));*/
        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height -= appendHeight;
        listView.setLayoutParams(params);
    }
    
    /**
     *  判断点击屏幕的位置是不是在指定的view上
     * @param view 
     * @param ev
     * @return
     */
    public static boolean inRangeOfView(View view, MotionEvent ev) {
		int[] location = new int[2];
		view.getLocationOnScreen(location);
		int x = location[0];
		int y = location[1];
		if (ev.getX() < x || ev.getX() > (x + view.getWidth()) || ev.getY() < y
				|| ev.getY() > (y + view.getHeight())) {
			return false;
		}
		return true;
	}
}