高仿优酷Android客户端图片左右滑动（自动切换）

本例是用ViewPager去做的实现，支持自动滑动和手动滑动，不仅优酷网，实际上有很多商城和门户网站都有类似的实现:

具体思路：

1. 工程中需要添加android-support-v4.jar,才能使用ViewPager控件.

2. 图片的自动切换: 可使用Timer或者ScheduledExecutorService,这个有多重方式可以实现.

同时要切换底部的dots（园点）

3.Handler+Message机制更新UI,这个相信大家都很熟练，不再描述

4. 实现的一些细节:注意本例中的优化：图片的自动切换启动了其他的线程，要在Activity在可见到不可见的状态,也就是在onStop()方法中将线程停止，在onStart()方法中开启线程。否则，Timer没有停止，或者反复开启，会引起较大的内存消耗，时间一长就程序就会崩掉。 还有，就是在跳转到其他Activity的过程中会出现画面的卡顿

下面看一下效果图和具体代码:





工程结构如下图所示：

main.xml:



[java] view plaincopyprint?

然后是具体的布局文件及代码实现:

<?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:background="#FFFFFF"

android:orientation="vertical" >

<RelativeLayout

android:layout_width="fill_parent"

android:layout_height="40dip"

android:background="@drawable/title_bk" >

<ImageButton

android:id="@+id/btn_back"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:background="@drawable/btn_back_selector"

android:src="@drawable/btn_back" />

<View

android:id="@+id/line0"

android:layout_width="1px"

android:layout_height="fill_parent"

android:layout_toRightOf="@id/btn_back"

android:background="#aa11264f" />

<View

android:layout_width="1px"

android:layout_height="fill_parent"

android:layout_toRightOf="@id/line0"

android:background="#009ad6" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerInParent="true"

android:text="优酷客户端"

android:textColor="#FFFFFF"

android:textSize="20sp" />

</RelativeLayout>

<FrameLayout

android:layout_width="fill_parent"

android:layout_height="140dip" >

<android.support.v4.view.ViewPager

android:id="@+id/vp"

android:layout_width="fill_parent"

android:layout_height="fill_parent" />

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="35dip"

android:layout_gravity="bottom"

android:background="#33000000"

android:gravity="center"

android:orientation="vertical" >

<TextView

android:id="@+id/tv_title"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="中国家庭院校园区域名字体现"

android:textColor="#ffffff" />

<LinearLayout

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="3dip"

android:gravity="center" >

<View

android:id="@+id/v_dot0"

style="@style/dot_style"

android:background="@drawable/dot_focused" />

<View

android:id="@+id/v_dot1"

style="@style/dot_style" />

<View

android:id="@+id/v_dot2"

style="@style/dot_style" />

<View

android:id="@+id/v_dot3"

style="@style/dot_style" />

<View

android:id="@+id/v_dot4"

style="@style/dot_style" />

</LinearLayout>

</LinearLayout>

</FrameLayout>

</LinearLayout>

MyViewPagerActivity:

[java] view plaincopyprint?

package com.tony.viewpager;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.Executors;

import java.util.concurrent.ScheduledExecutorService;

import java.util.concurrent.TimeUnit;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

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.View;

import android.widget.ImageView;

import android.widget.ImageView.ScaleType;

import android.widget.TextView;

/**

* 仿优酷Android客户端图片左右滑动

*

*/

public class MyViewPagerActivity extends Activity {

private ViewPager viewPager; // android-support-v4中的滑动组件

private List<ImageView> imageViews; // 滑动的图片集合

private String[] titles; // 图片标题

private int[] imageResId; // 图片ID

private List<View> dots; // 图片标题正文的那些点

private TextView tv_title;

private int currentItem = 0; // 当前图片的索引号

// An ExecutorService that can schedule commands to run after a given delay,

// or to execute periodically.

private ScheduledExecutorService scheduledExecutorService;

// 切换当前显示的图片

private Handler handler = new Handler() {

public void handleMessage(android.os.Message msg) {

viewPager.setCurrentItem(currentItem);// 切换当前显示的图片

};

};

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

imageResId = new int[] { R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d, R.drawable.e };

titles = new String[imageResId.length];

titles[0] = "巩俐不低俗，我就不能低俗";

titles[1] = "扑树又回来啦！再唱经典老歌引万人大合唱";

titles[2] = "揭秘北京电影如何升级";

titles[3] = "乐视网TV版大派送";

titles[4] = "热血屌丝的反杀";

imageViews = new ArrayList<ImageView>();

// 初始化图片资源

for (int i = 0; i < imageResId.length; i++) {

ImageView imageView = new ImageView(this);

imageView.setImageResource(imageResId[i]);

imageView.setScaleType(ScaleType.CENTER_CROP);

imageViews.add(imageView);

}

dots = new ArrayList<View>();

dots.add(findViewById(R.id.v_dot0));

dots.add(findViewById(R.id.v_dot1));

dots.add(findViewById(R.id.v_dot2));

dots.add(findViewById(R.id.v_dot3));

dots.add(findViewById(R.id.v_dot4));

tv_title = (TextView) findViewById(R.id.tv_title);

tv_title.setText(titles[0]);//

viewPager = (ViewPager) findViewById(R.id.vp);

viewPager.setAdapter(new MyAdapter());// 设置填充ViewPager页面的适配器

// 设置一个监听器，当ViewPager中的页面改变时调用

viewPager.setOnPageChangeListener(new MyPageChangeListener());

}

@Override

protected void onStart() {

scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();

// 当Activity显示出来后，每两秒钟切换一次图片显示

scheduledExecutorService.scheduleAtFixedRate(new ScrollTask(), 1, 2, TimeUnit.SECONDS);

super.onStart();

}

@Override

protected void onStop() {

// 当Activity不可见的时候停止切换

scheduledExecutorService.shutdown();

super.onStop();

}

/**

* 换行切换任务

*

* @author Administrator

*

*/

private class ScrollTask implements Runnable {

public void run() {

synchronized (viewPager) {

System.out.println("currentItem: " + currentItem);

currentItem = (currentItem + 1) % imageViews.size();

handler.obtainMessage().sendToTarget(); // 通过Handler切换图片

}

}

}

/**

* 当ViewPager中页面的状态发生改变时调用

*

* @author Administrator

*

*/

private class MyPageChangeListener implements OnPageChangeListener {

private int oldPosition = 0;

/**

* This method will be invoked when a new page becomes selected.

* position: Position index of the new selected page.

*/

public void onPageSelected(int position) {

currentItem = position;

tv_title.setText(titles[position]);

dots.get(oldPosition).setBackgroundResource(R.drawable.dot_normal);

dots.get(position).setBackgroundResource(R.drawable.dot_focused);

oldPosition = position;

}

public void onPageScrollStateChanged(int arg0) {

}

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

}

}

/**

* 填充ViewPager页面的适配器

*

* @author Administrator

*

*/

private class MyAdapter extends PagerAdapter {

@Override

public int getCount() {

return imageResId.length;

}

@Override

public Object instantiateItem(View arg0, int arg1) {

((ViewPager) arg0).addView(imageViews.get(arg1));

return imageViews.get(arg1);

}

@Override

public void destroyItem(View arg0, int arg1, Object arg2) {

((ViewPager) arg0).removeView((View) arg2);

}

@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) {

}

@Override

public void finishUpdate(View arg0) {

}

}

}

Drawable目录下 btn_back_selector.xml:

[java] view plaincopyprint?

<?xml version="1.0" encoding="utf-8"?>

<selector xmlns:android="http://schemas.android.com/apk/res/android">

<item android:drawable="@drawable/btn_top_pressed" android:state_focused="true"></item>

<item android:drawable="@drawable/btn_top_pressed" android:state_pressed="true"></item>

<item android:drawable="@drawable/btn_top_pressed" android:state_selected="true"></item>

<item android:drawable="@drawable/title_bk"></item>

</selector>

btn_top_pressed.xml:

[java] view plaincopyprint?

<?xml version="1.0" encoding="utf-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

android:shape="rectangle" >

<gradient

android:angle="270"

android:endColor="#009ad6"

android:startColor="#11264f" />

</shape>

dot_focused.xml:

[java] view plaincopyprint?

<?xml version="1.0" encoding="utf-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

android:shape="oval" >

<solid android:color="#aaFFFFFF" />

<corners android:radius="5dip" />

</shape>

dot_normal.xml:

[java] view plaincopyprint?

<?xml version="1.0" encoding="utf-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

android:shape="oval" >

<solid android:color="#33000000" />

<corners android:radius="5dip" />

</shape>

title_bk.xml:

[java] view plaincopyprint?

<?xml version="1.0" encoding="utf-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

android:shape="rectangle" >

<gradient

android:angle="270"

android:endColor="#11264f"

android:startColor="#009ad6" />

</shape>