Android ViewPager+Handler实现无限轮播和监听处理事件时轮播速度越来越快的问题解决

本文主要是介绍Android ViewPager+Handler实现无限轮播和监听处理事件时轮播速度越来越快的问题解决，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

大家都知道android的无限轮播实现的方法有很多，我们先来看看ViewPager+Handler吧：

一.ViewPager+Handler实现无限轮播    点击下载源码

package com.demo.sb.main;import java.util.ArrayList;
import com.demo.sb.utils.DensityUtil;
import com.demo.suibian.R;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;public class MActivity_Luenbo extends Activity {private ViewPager viewPager;private LinearLayout group;private int[] images = { R.drawable.a, R.drawable.c, R.drawable.d,R.drawable.guide_1, R.drawable.guide_2 };private ArrayList<ImageView> mImageViewList;private ImageView[] diandian;// ViewPager上的点点private int selectedItem = 0;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.mactivity_luenbo);viewPager = (ViewPager) findViewById(R.id.vp_viewPager);group = (LinearLayout) findViewById(R.id.ll_viewGroup);init();}@SuppressLint("HandlerLeak")private Handler mHandler = new Handler() {public void handleMessage(android.os.Message msg) {viewPager.setCurrentItem(selectedItem + 1);mHandler.sendEmptyMessageDelayed(0, 3000);};};private void init() {// TODO Auto-generated method stub// 引导3个ViewPagermImageViewList = new ArrayList<ImageView>();for (int i = 0; i < images.length; i++) {ImageView imageView = new ImageView(this);imageView.setBackgroundResource(images[i]);mImageViewList.add(imageView);}// 将点点加入到ViewGroup中diandian = new ImageView[images.length];for (int i = 0; i < images.length; i++) {// 循环加入点点图片组diandian[i] = new ImageView(this);if (i == 0) {diandian[i].setImageResource(R.drawable.page_indicator_focused);} else {diandian[i].setImageResource(R.drawable.page_indicator_unfocused);}diandian[i].setPadding(8, 8, 8, 8);group.addView(diandian[i]);}viewPager.setAdapter(new GuideAdapter());// 设置监听，主要是设置点点的背景viewPager.setOnPageChangeListener(new GuidePagerListener());// 设置ViewPager的默认项，设置为长度的1000倍，这样开始就能向左滑动了viewPager.setCurrentItem((images.length) * 1000);}/*** 每次当onResume有焦点时发送个空消息开始轮播*/@Overrideprotected void onResume() {// TODO Auto-generated method stubsuper.onResume();mHandler.sendEmptyMessageDelayed(0, 2000);}/*** 当暂停时停止轮播*/@Overrideprotected void onPause() {// TODO Auto-generated method stubsuper.onPause();mHandler.removeCallbacksAndMessages(null);}/*** ViewPager的适配器* */private class GuideAdapter extends PagerAdapter {@Overridepublic int getCount() {// TODO Auto-generated method stubreturn Integer.MAX_VALUE;}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {// TODO Auto-generated method stubreturn arg0 == arg1;}// @Override// public void destroyItem(View container, int position, Object object)// {// // TODO Auto-generated method stub// ((ViewGroup) container).removeView(images[position// % images.length]);// }@Overridepublic void destroyItem(ViewGroup container, int position, Object object) {// TODO Auto-generated method stubcontainer.removeView((View) object);}/*** 加载图片进去，用当前的position除以图片数组长度取余数是关键*/@Overridepublic Object instantiateItem(ViewGroup container, int position) {// TODO Auto-generated method stubfinal int currentIten = position % images.length;ImageView iView = mImageViewList.get(currentIten);try {if (iView.getParent() == null) {container.addView(iView);}iView.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubDensityUtil.showToast(MActivity_Luenbo.this,currentIten + "");}});iView.setOnTouchListener(new NewTouchListener());} catch (Exception e) {// TODO: handle exception}return iView;}}/*** ViewPager 的滑动监听* * @author Administrator* */private class GuidePagerListener implements OnPageChangeListener {@Overridepublic void onPageScrollStateChanged(int arg0) {// TODO Auto-generated method stub}@Overridepublic void onPageScrolled(int arg0, float arg1, int arg2) {// TODO Auto-generated method stubSystem.out.println(arg0 + "  dd " + arg1 + "  dddd  " + arg2);}@Overridepublic void onPageSelected(int position) {// TODO Auto-generated method stubselectedItem = position;System.out.println("第几个页面" + position + "  " + position% mImageViewList.size());for (int i = 0; i < diandian.length; i++) {if (i == position % images.length) {diandian[i].setImageResource(R.drawable.page_indicator_focused);} else {diandian[i].setImageResource(R.drawable.page_indicator_unfocused);}}}}/*** ViewPager的触摸事件当按下图片停止轮播* * @author Administrator* */private class NewTouchListener implements OnTouchListener {@Overridepublic boolean onTouch(View arg0, MotionEvent arg1) {// TODO Auto-generated method stubswitch (arg1.getAction()) {case MotionEvent.ACTION_DOWN:mHandler.removeCallbacksAndMessages(null);break;case MotionEvent.ACTION_CANCEL:mHandler.sendEmptyMessageDelayed(0, 3000);break;case MotionEvent.ACTION_UP:mHandler.sendEmptyMessageDelayed(0, 3000);break;default:break;}return true;}}}

1 .在ViewPager的适配器中的getCount()长度设置无限大Integer.MAX_VALUE
2 . 明白当前currentIten 为position % images.length;
3 . 设置一开始ViewPager的位置 viewPager.setCurrentItem((images.length) * 1000);这样刚开始就可以向左滑动了
4 . 在OnPageChangeListener ViewPager的滑动监听中设置小点的位置
5 . 设置Handler 定时滑动开启滑动
6 . 在onResume中发送空消息，在onPause中移除消息将所有的Callbacks和Messages全部清除掉，避免内存泄露。

上面这种的无限轮播要注意一个问题，那就是轮播图在滑动的后会越来越快，这要注意下面的触摸监听了：

  /*** ViewPager的触摸事件当按下图片停止轮播* * @author Administrator* */private class NewTouchListener implements OnTouchListener {@Overridepublic boolean onTouch(View arg0, MotionEvent arg1) {// TODO Auto-generated method stubswitch (arg1.getAction()) {case MotionEvent.ACTION_DOWN:mHandler.removeCallbacksAndMessages(null);break;case MotionEvent.ACTION_CANCEL:mHandler.sendEmptyMessageDelayed(0, 3000);break;case MotionEvent.ACTION_UP:mHandler.sendEmptyMessageDelayed(0, 3000);break;default:break;}return true;}}

在按下的时候加入下面的一行代码：

mHandler.removeCallbacksAndMessages(null);

二.UltraViewPager来实现，用UltraViewPager可以很简单的实现无限轮播      点击下载源码

1.布局：

<?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:layout_width="match_parent"android:layout_height="match_parent"tools:context="com.xieer.citybike.app.activity.guide.GuideActivity"><com.tmall.ultraviewpager.UltraViewPagerandroid:id="@+id/ultra_viewpager"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@android:color/darker_gray" /><Buttonandroid:id="@+id/guide_start"android:layout_width="90dp"android:layout_height="40dp"android:background="#FCCCC7"android:textSize="12sp"android:textColor="#D0525D"android:layout_alignParentBottom="true"android:layout_centerHorizontal="true"android:layout_marginBottom="50dp"android:text="开始"android:visibility="gone" />
</RelativeLayout>

2.代码:

import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;import com.tmall.ultraviewpager.UltraViewPager;
import com.xieer.citybike.app.MainActivity;
import com.xieer.citybike.app.R;
import com.xieer.citybike.app.adapter.PageMyAdapter;
import com.xieer.citybike.app.utils.common.ToastUtils;import java.util.ArrayList;/*** 引导页面* 使用UltraViewPager 来实现的轮播效果* */
public class GuideActivity extends AppCompatActivity {private SharedPreferences sPreferences;private ArrayList<ImageView> mdata;private static final int[] mImageIds = new int[]{R.drawable.guide_1,R.drawable.guide_2,R.drawable.guide_3};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_guide);mdata = new ArrayList<>();for(int i=0;i<mImageIds.length;i++){ImageView imageView = new ImageView(this);imageView.setBackgroundResource(mImageIds[i]);mdata.add(imageView);}sPreferences = getSharedPreferences("info",MODE_PRIVATE);final Button btn_start = (Button)findViewById(R.id.guide_start);UltraViewPager ultraViewPager = (UltraViewPager)findViewById(R.id.ultra_viewpager);ultraViewPager.setScrollMode(UltraViewPager.ScrollMode.HORIZONTAL);PagerAdapter adapter = new PageMyAdapter(this,mdata);ultraViewPager.setAdapter(adapter);//设置indicator样式ultraViewPager.initIndicator();ultraViewPager.getIndicator().setOrientation(UltraViewPager.Orientation.HORIZONTAL).setFocusColor(Color.GREEN).setNormalColor(Color.WHITE).setMargin(0,0,0, ToastUtils.dp2px(this,10)).setRadius((int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,ToastUtils.dp2px(this,4),this.getResources().getDisplayMetrics()));ultraViewPager.getIndicator().setGravity(Gravity.CENTER_HORIZONTAL | Gravity.BOTTOM);ultraViewPager.getIndicator().build();ultraViewPager.setInfiniteLoop(false);ultraViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){@Overridepublic void onPageSelected(int position) {super.onPageSelected(position);if(position == mdata.size() - 1){btn_start.setVisibility(View.VISIBLE);}else {btn_start.setVisibility(View.GONE);}}});btn_start.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {sPreferences.edit().putBoolean("isLoad",false).commit();startActivity(new Intent(GuideActivity.this, MainActivity.class));finish();}});}
}

三. RollViewPager无限轮播点击，代码就不贴了，需要的可以私聊，直接发你    点击下载源码

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