Android实现背景图片轮播

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context=".main2activity"
  android:orientation="vertical"
  android:gravity="center">
 
  <linearlayout
    android:layout_width="match_parent"
    android:layout_height="350dp">
 
    <android.support.v7.widget.appcompatimageview
      android:id="@+id/img1"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:src="@mipmap/img1" />
 
    <android.support.v7.widget.appcompatimageview
      android:id="@+id/img2"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:src="@mipmap/img2" />
 
    <android.support.v7.widget.appcompatimageview
      android:id="@+id/img3"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:src="@mipmap/img3" />
  </linearlayout>
 
  <linearlayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">
 
    <button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="切换图片" />
 
    <button
      android:id="@+id/button2"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="返回主页" />
 
  </linearlayout>
 
</linearlayout>

package com.example.administrator.demo2;
 
import android.content.intent;
import android.media.image;
import android.support.v7.app.appcompatactivity;
import android.os.bundle;
import android.view.view;
import android.widget.button;
import android.widget.imageview;
 
public class main2activity extends appcompatactivity {
  //定义所有的轮播图片
  int[] image = new int[]{
      r.mipmap.img1,
      r.mipmap.img2,
      r.mipmap.img3
  };
  //定义初始下标为0
  int index = 0;
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main2);
    //获取imageview
    final imageview img = (imageview) findviewbyid(r.id.img1);
    img.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view v) {
        if (index>=2){
          index=-1;
        }
        //改变imageview中的src属性值
        img.setimageresource(image[++index]);
      }
    });
 
    button button = (button) findviewbyid(r.id.button);
    button.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view v) {
        if (index>=2)
          index=-1;
        //改变imageview中的src属性值
        img.setimageresource(image[++index]);
      }
    });
 
    button ubt1 = (button) findviewbyid(r.id.button2);
    ubt1.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view v) {
        intent it = new intent();
        it.setclass(main2activity.this,mainactivity.class);
        startactivity(it);
      }
    });
 
  }
}