Android利用ViewPager实现滑动广告板

•android-support-v4.jar,这是谷歌官方给我们提供的一个兼容低版本Android设备的软件包，里面包囊了只有在Android3.0以上可以使用的api。而ViewPager就是其中之一,利用它我们可以做很多事情，从最简单的导航，到页面切换菜单等等。

•ViewPager的功能就是可以使视图滑动，就像Lanucher左右滑动那样。

•本Demo向大家演示ViewPager的使用，并在用户未滑动View时，每隔5s钟自动切换到下一个View(循环切换)，而当用户有Touch到View时取消5s自动切换功能。并有指示器指示当前处于哪一个View。

下面是运行的截图：

这个是非常常见的应用

下面给出实现的代码：

1.源文件

package com.eyeandroid.viewpager;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;

@SuppressLint("HandlerLeak")
public class MainActivity extends Activity {
	private ImageView[] imageViews = null;
	private ImageView imageView = null;
	private ViewPager advPager = null;
	private AtomicInteger what = new AtomicInteger(0);
	private boolean isContinue = true;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		initViewPager();
	}


	private void initViewPager() {
		advPager = (ViewPager) findViewById(R.id.adv_pager);
		ViewGroup group = (ViewGroup) findViewById(R.id.viewGroup);

//		这里存放的是四张广告背景
		List<View> advPics = new ArrayList<View>();

		ImageView img1 = new ImageView(this);
		img1.setBackgroundResource(R.drawable.advertising_default_1);
		advPics.add(img1);

		ImageView img2 = new ImageView(this);
		img2.setBackgroundResource(R.drawable.advertising_default_2);
		advPics.add(img2);

		ImageView img3 = new ImageView(this);
		img3.setBackgroundResource(R.drawable.advertising_default_3);
		advPics.add(img3);

		ImageView img4 = new ImageView(this);
		img4.setBackgroundResource(R.drawable.advertising_default);
		advPics.add(img4);
		
//		对imageviews进行填充
		imageViews = new ImageView[advPics.size()];
//小图标
		for (int i = 0; i < advPics.size(); i++) {
			imageView = new ImageView(this);
			imageView.setLayoutParams(new LayoutParams(20, 20));
			imageView.setPadding(5, 5, 5, 5);
			imageViews[i] = imageView;
			if (i == 0) {
				imageViews[i]
						.setBackgroundResource(R.drawable.banner_dian_focus);
			} else {
				imageViews[i]
						.setBackgroundResource(R.drawable.banner_dian_blur);
			}
			group.addView(imageViews[i]);
		}

		advPager.setAdapter(new AdvAdapter(advPics));
		advPager.setOnPageChangeListener(new GuidePageChangeListener());
		advPager.setOnTouchListener(new OnTouchListener() {
			
			@Override
			public boolean onTouch(View v, MotionEvent event) {
				switch (event.getAction()) {
				case MotionEvent.ACTION_DOWN:
				case MotionEvent.ACTION_MOVE:
					isContinue = false;
					break;
				case MotionEvent.ACTION_UP:
					isContinue = true;
					break;
				default:
					isContinue = true;
					break;
				}
				return false;
			}
		});
		new Thread(new Runnable() {

			@Override
			public void run() {
				while (true) {
					if (isContinue) {
						viewHandler.sendEmptyMessage(what.get());
						whatOption();
					}
				}
			}

		}).start();
	}

	
	private void whatOption() {
		what.incrementAndGet();
		if (what.get() > imageViews.length - 1) {
			what.getAndAdd(-4);
		}
		try {
			Thread.sleep(5000);
		} catch (InterruptedException e) {
			
		}
	}

	private final Handler viewHandler = new Handler() {

		@Override
		public void handleMessage(Message msg) {
			advPager.setCurrentItem(msg.what);
			super.handleMessage(msg);
		}

	};

	private final class GuidePageChangeListener implements OnPageChangeListener {

		@Override
		public void onPageScrollStateChanged(int arg0) {

		}

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

		}

		@Override
		public void onPageSelected(int arg0) {
			what.getAndSet(arg0);
			for (int i = 0; i < imageViews.length; i++) {
				imageViews[arg0]
						.setBackgroundResource(R.drawable.banner_dian_focus);
				if (arg0 != i) {
					imageViews[i]
							.setBackgroundResource(R.drawable.banner_dian_blur);
				}
			}

		}

	}

	private final class AdvAdapter extends PagerAdapter {
		private List<View> views = null;

		public AdvAdapter(List<View> views) {
			this.views = views;
		}

		@Override
		public void destroyItem(View arg0, int arg1, Object arg2) {
			((ViewPager) arg0).removeView(views.get(arg1));
		}

		@Override
		public void finishUpdate(View arg0) {

		}

		@Override
		public int getCount() {
			return views.size();
		}

		@Override
		public Object instantiateItem(View arg0, int arg1) {
			((ViewPager) arg0).addView(views.get(arg1), 0);
			return views.get(arg1);
		}

		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			return arg0 == arg1;
		}

		@Override
		public void restoreState(Parcelable arg0, ClassLoader arg1) {

		}

		@Override
		public Parcelable saveState() {
			return null;
		}

		@Override
		public void startUpdate(View arg0) {

		}

	}

}

2.布局文件

这个文件在屏幕上的图片显示具有至关重要的作用

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

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical" >
        <!-- ViewPager是一个控件 -->
        <android.support.v4.view.ViewPager
            android:id="@+id/adv_pager"
            android:layout_width="fill_parent"
            android:layout_height="160dp" >
            
        </android.support.v4.view.ViewPager>
        <LinearLayout
            android:id="@+id/viewGroup"
            android:layout_below="@id/adv_pager"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="-25px"
            android:gravity="right"
            android:orientation="horizontal" >
        </LinearLayout>
    </RelativeLayout>

</LinearLayout>