ViewPager大图轮播

Posted 2022-12-06 猫叔聊技术

首先我们需要一个主布局文件activity_main.xml：

<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.support.v4.view.ViewPager
        android:id="@+id/vp_ad"
        android:layout_width="match_parent"
        android:layout_height="200dp" >
    </android.support.v4.view.ViewPager>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@id/vp_ad"
        android:background="#77000000"
        android:orientation="vertical"
        android:padding="8dp" >

        <TextView
            android:id="@+id/tv_ad"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:ellipsize="end"
            android:singleLine="true"
            android:text="我是文本"
            android:textColor="#fff" />

        <LinearLayout
            android:id="@+id/dot_layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="3dp"
            android:orientation="horizontal" >
        </LinearLayout>
    </LinearLayout>

</RelativeLayout>

创建了一个类 Ad.java

package com.xuhao.ad;

public class Ad 
	private int icon;
	private String desc;

	public Ad(int icon, String desc) 
		super();
		this.icon = icon;
		this.desc = desc;
	

	public int getIcon() 
		return icon;
	

	public void setIcon(int icon) 
		this.icon = icon;
	

	public String getDesc() 
		return desc;
	

	public void setDesc(String desc) 
		this.desc = desc;
	

接着就是mainactivity里面主要的功能实现了:

package com.xuhao.ad;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;

public class MainActivity extends Activity 
	private ViewPager vpad;
	private TextView tv;
	private List<Ad> list = new ArrayList<Ad>();
	private LinearLayout dot_layout;

	@Override
	protected void onCreate(Bundle savedInstanceState) 
		super.onCreate(savedInstanceState);
		initView();
		initListener();
		initData();

	

	private void initView() 
		setContentView(R.layout.activity_main);
		vpad = (ViewPager) findViewById(R.id.vp_ad);
		tv = (TextView) findViewById(R.id.tv_ad);
		dot_layout = (LinearLayout) findViewById(R.id.dot_layout);

	

	private void initListener() 
		vpad.setOnPageChangeListener(new OnPageChangeListener() 

			@Override
			public void onPageSelected(int arg0) 
				updateDocInfo();
			

			@Override
			public void onPageScrolled(int arg0, float arg1, int arg2) 
			

			@Override
			public void onPageScrollStateChanged(int arg0) 

			
		);
	

	private void initData() 
		list.add(new Ad(R.drawable.a, "巩俐不低俗，我就不能低俗"));
		list.add(new Ad(R.drawable.b, "朴树又回来了，再唱经典老歌引百万人同唱啊"));
		list.add(new Ad(R.drawable.c, "揭秘北京电影如何升级"));
		list.add(new Ad(R.drawable.d, "乐视网TV版大放送"));
		list.add(new Ad(R.drawable.e, "热血屌丝的反杀"));

		initDots();		
		vpad.setAdapter(new MyPagerAdapter());
		int c=(Integer.MAX_VALUE/2)%list.size();
		vpad.setCurrentItem(Integer.MAX_VALUE/2-c);
		updateDocInfo();
	

	/**
	 * 初始化点
	 */
	private void initDots() 
		for (int i = 0; i < list.size(); i++) 
			View view = new View(this);
			LayoutParams layoutParams = new LayoutParams(8, 8);
			if (i != 0) 
				layoutParams.leftMargin = 5;
			
			view.setLayoutParams(layoutParams);
			view.setBackgroundResource(R.drawable.selector_dot);
			dot_layout.addView(view);

		
	

	/**
	 * 更新文本以及点
	 */

	private void updateDocInfo() 
		int currentItem = vpad.getCurrentItem();
		int value=currentItem%list.size();
		tv.setText(list.get(value).getDesc());
		for (int i = 0; i < dot_layout.getChildCount(); i++) 
			dot_layout.getChildAt(i).setEnabled(i==value);
		

	

	private class MyPagerAdapter extends PagerAdapter 

		@Override
		public int getCount() 
			return Integer.MAX_VALUE;
		

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

		/**
		 * 相当于baseadpater中的getview()
		 */
		@Override
		public Object instantiateItem(ViewGroup container, int position) 
			View view = View.inflate(MainActivity.this, R.layout.activity_ad,
					null);
			ImageView im = (ImageView) view.findViewById(R.id.iv);

			Ad ad = list.get(position%list.size());

			im.setImageResource(ad.getIcon());

			container.addView(view);

			return view;
		

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

	

viewpager添加的一个视图activity_ad.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/iv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="fitXY"
        android:src="@drawable/a" />

</LinearLayout>

项目下载地址:https://github.com/xh2015/viewpager.git