本文实例为大家分享了Android实现ViewPager无限循环的具体代码，供大家参考，具体内容如下
方式一：
实现原理：
假设有3张图片，分别是1,2,3，那么就创建5张图片，这5张图片的顺序为：3,1,2,3,1，其中1,2,3为我们要实现滑动的图片，最左面的3和最右面的1是我们另外添加的图片，开始时，显示图片1，当图片向左滑动依次为1,2,3，当从第3张图片继续向左滑动，会出现我们多添加的图片1，这时，将当前的index设置为真正的图片1所在的位置。
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package com.xiaomai.myproject.demo;import android.os.Bundle;import android.os.Handler;import android.support.v4.view.ViewPager;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.LinearLayout;import com.xiaomai.myproject.R;import com.xiaomai.myproject.adapter.LoopViewPagerAdapter;import com.xiaomai.myproject.base.BaseActivity;import com.xiaomai.myproject.utils.Utils;import java.util.ArrayList;import java.util.List;/** * Created by XiaoMai on 2016/10/7 17:19. * */public class LoopViewPagerDemoActivity extends BaseActivity { /** * 更新图片的时间 */ private static final int UPDATE_TIME = 3 * 1000; private ViewPager mViewPager; private LoopViewPagerAdapter mLoopViewPager; /** * 图片资源集合 */ private int[] mImageIds; /** * 图片集合 */ private List<ImageView> mImageList; /** * 当前广告的index */ private int mCurrentPageIndex; /** * 指示Point */ private LinearLayout mLinearLayoutPoints; private Handler mHandler = new Handler(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override protected void onResume() { super.onResume(); mHandler.postDelayed(myRunnable, UPDATE_TIME); } @Override protected void onPause() { super.onPause(); mHandler.removeCallbacks(myRunnable); } Runnable myRunnable = new Runnable() { @Override public void run() { mViewPager.setCurrentItem(mCurrentPageIndex + 1); } }; @Override protected void initVariables() { super.initVariables(); } @Override protected void initViews() { mLinearLayoutPoints = (LinearLayout) findViewById(R.id.activity_ll_container); mViewPager = (ViewPager) findViewById(R.id.activity_loop_viewpager); } @Override protected void loadData() { super.loadData(); mHandler.postDelayed(new Runnable() { @Override public void run() { /** * 初始化图片的资源id */ mImageIds = new int[]{ R.mipmap.ic_launcher, R.mipmap.ic_launcher, R.drawable.my_toast, R.drawable.my_toast}; /** * 添加ImageView */ mImageList = new ArrayList<>(); //额外添加两张图片 int pagerCount = mImageIds.length + 2; ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams( ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); for (int i = 0; i < pagerCount; i++) { ImageView imageView = new ImageView(mContext); imageView.setLayoutParams(layoutParams); mImageList.add(imageView); } //圆点的直径 int diameter = Utils.dip2px(mContext,10f); LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(diameter, diameter); int margin = Utils.dip2px(mContext,5f); params.setMargins(margin,margin,margin,margin); mLinearLayoutPoints.removeAllViews(); for (int i = 0; i < mImageList.size(); i++) { View view = new View(mContext); view.setLayoutParams(params); if (i != 0 && i != mImageList.size() - 1) { view.setBackgroundResource(R.drawable.circle_normal); } mLinearLayoutPoints.addView(view); } mLinearLayoutPoints.setVisibility(View.VISIBLE); mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { mHandler.removeCallbacks(myRunnable); mHandler.postDelayed(myRunnable, UPDATE_TIME); mCurrentPageIndex = position; if (position == 0) { // 当视图在第一个时，将页面号设置为图片的最后一张。 mCurrentPageIndex = mImageIds.length; } else if (position == mImageIds.length + 1) { // 当视图在最后一个时,将页面号设置为图片的第一张。 mCurrentPageIndex = 1; } else { } /** * 当视图在第一个或者最后一个时，pageIndex和position的值不相等， * 所以要改变viewPager的当前item。 */ if (position != mCurrentPageIndex) { /** * 第二参数必须设置为false，意思是立即过渡，不给用户视觉上的效果。 */ mViewPager.setCurrentItem(mCurrentPageIndex, false); return; } for (int i = 1; i < mLinearLayoutPoints.getChildCount() - 1; i++) { if (i != mCurrentPageIndex){ mLinearLayoutPoints.getChildAt(i).setBackgroundResource(R.drawable.circle_normal); }else { mLinearLayoutPoints.getChildAt(mCurrentPageIndex).setBackgroundResource( R.drawable.circle_select); } } } @Override public void onPageScrollStateChanged(int state) { } }); /** * 当ViewPager被按下的时候，取消自动滚动 * 反之开启自动滑动。 */ mViewPager.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { if(event.getAction() == MotionEvent.ACTION_DOWN){ mHandler.removeCallbacks(myRunnable); }else if (event.getAction() == MotionEvent.ACTION_UP){ mHandler.postDelayed(myRunnable, UPDATE_TIME); } return false; } }); mLoopViewPager = new LoopViewPagerAdapter(mImageList, mImageIds); mViewPager.setAdapter(mLoopViewPager); /** * 因为第0个item是另外添加的那张图片，所以初始化时要把当前item设置为1。 */ mViewPager.setCurrentItem(1); dissMissProgressDialog(); } }, 3 * 1000); } @Override protected int getContentLayout() { return R.layout.act_loopviewpager; }} |
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package com.xiaomai.myproject.adapter;import android.support.v4.view.PagerAdapter;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import java.util.List;/** * Created by XiaoMai on 2016/10/7 17:23. */public class LoopViewPagerAdapter extends PagerAdapter { private List<ImageView> mImageList; private int[] mImageIds; public LoopViewPagerAdapter(List<ImageView> mImageList, int[] mImageIds) { this.mImageList = mImageList; this.mImageIds = mImageIds; } @Override public int getCount() { return mImageList == null ? 0 : mImageList.size(); } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } @Override public Object instantiateItem(ViewGroup container, int position) { if (position == 0) { // 如果是第0个item就设置它的图片内容为最后一个图片的内容 mImageList.get(position).setImageResource(mImageIds[mImageIds.length-1]); } else if (position == (mImageList.size() - 1)) { // 如果是最后一个item就设置它的图片内容为第一个图片的内容 mImageList.get(position).setImageResource(mImageIds[0]); } else { // 这是正常的图片 mImageList.get(position).setImageResource(mImageIds[position - 1]); } container.addView(mImageList.get(position)); return mImageList.get(position); } @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView(mImageList.get(position)); }} |
布局文件
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<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <include android:id="@+id/titleBar" layout="@layout/my_app_bar" /> <android.support.v4.view.ViewPager android:id="@+id/activity_loop_viewpager" android:layout_width="match_parent" android:layout_height="200dp" android:layout_below="@id/titleBar" /> <LinearLayout android:id="@+id/activity_ll_container" android:layout_width="match_parent" android:orientation="horizontal" android:gravity="center" android:background="@color/toast" android:layout_alignBottom="@id/activity_loop_viewpager" android:visibility="gone" android:layout_height="40dp"/></RelativeLayout> |
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/xiaomai949804781/article/details/52779339
