android:theme="@style/Theme.AppCompat.Light.NoActionBar">

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.listview_unit4_1.MainActivity"> <ListView  android:id="@+id/list_view"  android:layout_width="match_parent"  android:layout_height="match_parent"/> <android.support.v7.widget.Toolbar  android:id="@+id/toolbar"  android:layout_width="match_parent"  android:layout_height="?attr/actionBarSize"  android:background="@color/colorPrimary"/></RelativeLayout>

package com.example.listview_unit4_1;import android.animation.ObjectAnimator;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.support.v7.widget.Toolbar;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.view.ViewConfiguration;import android.widget.ArrayAdapter;import android.widget.ListView;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity { private ListView listView; private List<String> listViewData;//數(shù)據(jù)源 private ArrayAdapter<String> adapter; private Toolbar toolbar; private int mTouchSlop;//系統(tǒng)認(rèn)為的最小滑動(dòng)距離 private float mFirstY;//用戶首次觸摸的Y坐標(biāo) private float mLastY;//用戶滑動(dòng)結(jié)束時(shí)Y坐標(biāo) private ObjectAnimator mAnimator;//將控件與動(dòng)畫(huà)聯(lián)系起來(lái)的類(lèi)（可以使指定的控件，實(shí)現(xiàn)指定的動(dòng)畫(huà)效果） private boolean mShow;//toolbar是否顯示 @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  toolbar = (Toolbar) findViewById(R.id.toolbar);  setSupportActionBar(toolbar);  //初始化數(shù)據(jù)源  initData();  listView = (ListView) findViewById(R.id.list_view);  //為L(zhǎng)istView增加一個(gè)HeadView(避免第一個(gè)Item被toolbar遮擋)  //abc_action_bar_default_height_material屬性獲取系統(tǒng)actionBar的高度  View headView = new View(this);  headView.setLayoutParams(new ListView.LayoutParams(ListView.LayoutParams.MATCH_PARENT,    (int)getResources().getDimension(R.dimen.abc_action_bar_default_height_material)));  listView.addHeaderView(headView);  //獲取系統(tǒng)定義的最低滑動(dòng)距離  mTouchSlop = ViewConfiguration.get(this).getScaledTouchSlop();  adapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, listViewData);  listView.setAdapter(adapter);  //為L(zhǎng)istView設(shè)置觸摸事件監(jiān)聽(tīng)  listView.setOnTouchListener(new View.OnTouchListener() {   @Override   public boolean onTouch(View v, MotionEvent event) {    switch (event.getAction()){     case MotionEvent.ACTION_DOWN:      mFirstY = event.getY();//getY獲取的是相對(duì)于View的坐標(biāo)，getRawY獲取的是相對(duì)于屏幕的坐標(biāo)      break;     case MotionEvent.ACTION_MOVE:      mLastY = event.getY();      if(mLastY - mFirstY > mTouchSlop){//手指向下滑動(dòng)，顯示toolbar       if(!mShow){        Log.i("tag", "mLastY_手指下滑="+mLastY);        toolbarAnim(0);//顯示        mShow = !mShow;       }      }else if(mFirstY - mLastY > mTouchSlop){//手指向上滑動(dòng)，隱藏toolbar       if(mShow){        Log.i("tag", "mLastY_手指上滑="+mLastY);        toolbarAnim(1);//隱藏        mShow = !mShow;       }      }      break;     default:break;    }    return false;//一般返回false，提交給上級(jí)   }  }); } public void toolbarAnim(int flag){  if(mAnimator != null && mAnimator.isRunning()){   mAnimator.cancel();  }  if(flag == 0){   Log.i("tag", "手指下滑,》》》》》》》顯示");   mAnimator = ObjectAnimator.ofFloat(toolbar, "translationY", toolbar.getTranslationY(), 0);  }else if(flag == 1){   Log.i("tag", "手指上滑，》》》》》》》隱藏");   mAnimator = ObjectAnimator.ofFloat(toolbar, "translationY", toolbar.getTranslationY(),     -toolbar.getHeight());  }  mAnimator.start();//開(kāi)始動(dòng)畫(huà) } /**  * 初始化ListView的數(shù)據(jù)源  */ public void initData(){  listViewData = new ArrayList<>();  String s;  for(int i = 0; i < 20; i ++){   s = ""+i;   listViewData.add(s);  } }}

//第一個(gè)參數(shù)用于指定這個(gè)動(dòng)畫(huà)要操作的是哪個(gè)控件//第二個(gè)參數(shù)用于指定這個(gè)動(dòng)畫(huà)要操作這個(gè)控件的哪個(gè)屬性//第三個(gè)參數(shù)是可變長(zhǎng)參數(shù),指這個(gè)屬性值是從多少變到多少mAnimator = ObjectAnimator.ofFloat(toolbar, "translationY", toolbar.getTranslationY(), 0);mAnimator = ObjectAnimator.ofFloat(toolbar, "translationY", toolbar.getTranslationY(),     -toolbar.getHeight());