无限轮播 viewpager

最新推荐文章于 2020-05-21 14:35:23 发布

Guiyide

最新推荐文章于 2020-05-21 14:35:23 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/Guiyide/article/details/78531587

本文介绍了一个基于Android的简单应用程序，该应用使用ViewPager实现图片轮播功能，并通过Handler和Timer进行自动切换。同时，利用RadioGroup来显示当前轮播的位置。

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package com.lbs.rikao13;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.RadioGroup;

import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity {
    int[] tu = {R.drawable.b, R.drawable.c, R.drawable.d};
    private ViewPager vp;


    Handler handler = new Handler() {
        int i = 0;

        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            vp.setCurrentItem(i % tu.length);
            i++;
        }
    };
    private RadioGroup rg;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        vp = findViewById(R.id.vp);
        rg = findViewById(R.id.rg);
        mypageada mp = new mypageada();
        vp.setAdapter(mp);
        timerdingshi();
        vp.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                switch (position) {
                    case 0:
                        RadioButton rb1 = (RadioButton) findViewById(R.id.rb1);
                        rb1.setChecked(true);
                        break;
                    case 1:
                        RadioButton rb2 = (RadioButton) findViewById(R.id.rb2);
                        rb2.setChecked(true);
                        break;
                    case 2:
                        RadioButton rb3 = (RadioButton) findViewById(R.id.rb3);
                        rb3.setChecked(true);
                        break;
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
    }

    private void timerdingshi() {
        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                handler.sendEmptyMessage(1);
            }
        }, 0, 1000);
    }

    class mypageada extends PagerAdapter {
        @Override
        public int getCount() {
            return tu.length;
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            ImageView iv = new ImageView(MainActivity.this);
            iv.setImageResource(tu[position]);
            container.addView(iv);
            return iv;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            container.removeView((View) object);
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }
    }
}









<?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"
    android:orientation="vertical"
    tools:context="com.lbs.rikao13.MainActivity">

    <android.support.v4.view.ViewPager
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:id="@+id/vp"
        />
    <RadioGroup
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/rg">
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/rb1"/>
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/rb2"/>
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/rb3"/>
    </RadioGroup>
</LinearLayout>