浅谈ListView滑动隐藏显示ToolBar

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <RelativeLayout
 3     xmlns:android="http://schemas.android.com/apk/res/android"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent">
 6 
 7     <ListView
 8         android:layout_width="match_parent"
 9         android:layout_height="match_parent"
10         android:background="#f2f2f2"
11         android:divider="#abcdee"
12         android:dividerHeight="1px"
13         android:id="@+id/listView">
14         
15     </ListView>
16 
17     <!--ToolBar-->
18     <android.support.v7.widget.Toolbar
19         android:layout_width="match_parent"
20         android:layout_height="wrap_content"
21         android:background="#4097e6"
22         android:id="@+id/toolBar">
23         
24     </android.support.v7.widget.Toolbar>
25     
26 </RelativeLayout>

  1 package com.research.gong.android_view_research;
  2 
  3 import android.animation.ObjectAnimator;
  4 import android.app.Activity;
  5 import android.os.Bundle;
  6 import android.support.v7.widget.Toolbar;
  7 import android.view.MotionEvent;
  8 import android.view.View;
  9 import android.view.ViewConfiguration;
 10 import android.widget.AbsListView;
 11 import android.widget.ArrayAdapter;
 12 import android.widget.ListView;
 13 
 14 public class MainActivity extends Activity {
 15 
 16     private ListView listView;
 17     String[] datas = {"A1", "A2", "A3", "A4", "A5", "A6", "A7", "A8", "A9", "A10",
 18             "A11", "A12", "A13", "A14", "A15", "A16", "A17", "A18", "A19", "A20"};
 19     private float scaledTouchSlop;
 20     private float firstY = 0;
 21     private Toolbar toolbar;
 22     private ObjectAnimator animtor;
 23 
 24     @Override
 25     protected void onCreate(Bundle savedInstanceState) {
 26         super.onCreate(savedInstanceState);
 27         setContentView(R.layout.activity_main);
 28         toolbar = (Toolbar) findViewById(R.id.toolBar);
 29         listView = (ListView) findViewById(R.id.listView);
 30         /**
 31          * 添加一个HeadView避免第一个Item被ToolBar遮挡
 32          * 必须在setAdapter之前进行设置
 33          */
 34         initHeadView();
 35         listView.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, datas));
 36         //判断认为是滑动的最小距离(乘以系数调整滑动灵敏度)
 37         scaledTouchSlop = ViewConfiguration.get(this).getScaledTouchSlop()*3.0f;
 38         /**
 39          * 设置触摸事件
 40          */
 41         listView.setOnTouchListener(new View.OnTouchListener() {
 42             private float currentY;
 43             private int direction=-1;
 44             private boolean mShow = true;
 45 
 46             @Override
 47             public boolean onTouch(View v, MotionEvent event) {
 48                 switch (event.getAction()) {
 49                     case MotionEvent.ACTION_DOWN:
 50                         firstY = event.getY();
 51                         break;
 52                     case MotionEvent.ACTION_MOVE:
 53                         currentY = event.getY();
 54                         //向下滑动
 55                         if (currentY - firstY > scaledTouchSlop) {
 56                             direction = 0;
 57                         }
 58                         //向上滑动
 59                         else if (firstY - currentY > scaledTouchSlop) {
 60                             direction = 1;
 61                         }
 62                         //如果是向上滑动，并且ToolBar是显示的，就隐藏ToolBar
 63                         if (direction == 1) {
 64                             if (mShow) {
 65                                 toobarAnim(1);
 66                                 mShow = !mShow;
 67                             }
 68                         } else if (direction == 0) {
 69                             if (!mShow) {
 70                                 toobarAnim(0);
 71                                 mShow = !mShow;
 72                             }
 73                         }
 74                         break;
 75                     case MotionEvent.ACTION_UP:
 76                         break;
 77                 }
 78                 return false;//注意此处不能返回true，因为如果返回true,onTouchEvent就无法执行，导致的后果是ListView无法滑动
 79             }
 80         });
 81     }
 82 
 83 
 84     /**
 85      * 设置头布局，注意：这个头布局的高度要和ToolBar的高度一致
 86      */
 87     public void initHeadView() {
 88         View view = new View(this);
 89         //abc_action_bar_default_height_material获取系统ActionBar的高度
 90         AbsListView.LayoutParams params = new AbsListView.LayoutParams
 91                 (AbsListView.LayoutParams.MATCH_PARENT,
 92                         (int) getResources().getDimension(R.dimen.abc_action_bar_default_height_material));
 93         view.setLayoutParams(params);
 94         listView.addHeaderView(view);
 95     }
 96 
 97     /**
 98      * ToolBar显示隐藏动画
 99      * @param direction
100      */
101     public void toobarAnim(int direction) {
102         //开始新的动画之前要先取消以前的动画
103         if (animtor != null && animtor.isRunning()) {
104             animtor.cancel();
105         }
106         //toolbar.getTranslationY()获取的是Toolbar距离自己顶部的距离
107         float translationY=toolbar.getTranslationY();
108         if (direction == 0) {
109             animtor = ObjectAnimator.ofFloat(toolbar, "translationY", translationY, 0);
110         } else if (direction == 1) {
111             animtor = ObjectAnimator.ofFloat(toolbar, "translationY", translationY, -toolbar.getHeight());
112         }
113         animtor.start();
114     }
115 }