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>
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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);
}
}
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以上就是本文的全部内容，希望对大家的学习有所帮助。