页面拖动到最后一页 再向下滑动回复到 第一页，第一页向前滑动回到 最后一页
同时，底部红色小圆点随着页面的滑动距离比例随时改变位置
布局：
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<?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" android:paddingbottom="@dimen/activity_vertical_margin" android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" tools:context="com.lian.viewpagertest.mainactivity"> <android.support.v4.view.viewpager android:id="@+id/viewpager" android:layout_width="match_parent" android:layout_height="match_parent" > </android.support.v4.view.viewpager> <textview android:id="@+id/tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="内容" android:textsize="25sp" android:layout_alignparentbottom="true" android:layout_centerhorizontal="true" /> <relativelayout android:id="@+id/rl_bottom" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignparentbottom="true" android:layout_centerhorizontal="true" android:layout_marginbottom="45dip" > <linearlayout android:id="@+id/ll_points" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" > </linearlayout> <view android:id="@+id/v_redpoint" android:layout_width="10dip" android:layout_height="10dip" android:background="@drawable/red_circle" /> </relativelayout> </relativelayout> |
其中red_circle是用shape绘制的红色小圆点
最后的linearlayout实际上是灰色小圆点的容器，在代码中根据数据的长度动态确定数目
代码：
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package com.lian.viewpagertest; import android.os.bundle; import android.support.v4.view.pageradapter; import android.support.v4.view.viewpager; import android.support.v7.app.appcompatactivity; import android.util.log; import android.view.view; import android.view.viewgroup; import android.view.viewtreeobserver; import android.widget.imageview; import android.widget.linearlayout; import android.widget.relativelayout; import android.widget.textview; import java.util.arraylist; import java.util.list; public class mainactivity extends appcompatactivity { private viewpager mviewpager; private textview mtextview; private linearlayout mlinearlayout; private view mview; private list<imageview> mdatalist; private int diatance; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); initview(); initdata(); initevent(); } /** * 初始化数据 */ private void initdata() { int[] sorce = new int[]{r.drawable.a,r.drawable.b,r.drawable.c,r.drawable.d,r.drawable.e}; mdatalist = new arraylist<imageview>(); for (int i = 0;i < sorce.length;i ++){ imageview img = new imageview(getapplicationcontext()); img.setimageresource(sorce[i]); mdatalist.add(img); //添加底部灰点 view v = new view(getapplicationcontext()); v.setbackgroundresource(r.drawable.gray_circle); //指定其大小 linearlayout.layoutparams params = new linearlayout.layoutparams(20,20); if (i != 0) params.leftmargin = 20; v.setlayoutparams(params); mlinearlayout.addview(v); } mviewpager.setadapter(new myadapter()); //设置每次加载时第一页在max_value / 2 - extra 页，造成用户无限轮播的错觉 int startpage = integer.max_value / 2; int extra = startpage % mdatalist.size(); startpage = startpage - extra; mviewpager.setcurrentitem(startpage); } /** * viewpager的容器 */ public class myadapter extends pageradapter{ @override public int getcount() { //告诉容器我们的数据长度为integer.max_value，这样就可以一直滚动 return integer.max_value; } @override public boolean isviewfromobject(view view, object object) { return view == object; } @override public object instantiateitem(viewgroup container, int position) { //若position超过mdatalist.size()，会发生越界异常，所以这里每次超过size又从0开始计算位置 position = position % mdatalist.size(); imageview img = mdatalist.get(position); container.addview(img); return img; } @override public void destroyitem(viewgroup container, int position, object object) { position = position % mdatalist.size(); container.removeview((view)object); // super.destroyitem(container, position, object); } } private void initevent() { /** * 当底部红色小圆点加载完成时测出两个小灰点的距离，便于计算后面小红点动态移动的距离 */ mview.getviewtreeobserver().addongloballayoutlistener(new viewtreeobserver.ongloballayoutlistener() { @override public void ongloballayout() { diatance = mlinearlayout.getchildat(1).getleft() - mlinearlayout.getchildat(0).getleft(); log.d("两点间距",diatance + "测出来了"); } }); mviewpager.setonpagechangelistener(new viewpager.onpagechangelistener() { @override public void onpagescrolled(int position, float positionoffset, int positionoffsetpixels) { //测出页面滚动时小红点移动的距离，并通过setlayoutparams(params)不断更新其位置 position = position % mdatalist.size(); float leftmargin = diatance * (position + positionoffset); relativelayout.layoutparams params = (relativelayout.layoutparams) mview.getlayoutparams(); params.leftmargin = math.round(leftmargin); mview.setlayoutparams(params); log.d("红点在这",leftmargin + ""); } @override public void onpageselected(int position) { } @override public void onpagescrollstatechanged(int state) { } }); } private void initview() { setcontentview(r.layout.activity_main); mviewpager = (viewpager) findviewbyid(r.id.viewpager); mtextview = (textview) findviewbyid(r.id.tv); mlinearlayout = (linearlayout) findviewbyid(r.id.ll_points); mview = findviewbyid(r.id.v_redpoint); } } |
以上就是本文的全部内容，希望对大家的学习有所帮助。
