高仿優酷Android客戶端圖片左右滑動（自動切換）

本例是用ViewPager去做的實現，支持自動滑動和手動滑動，不僅優酷網，實際上有很多商城和門戶網站都有類似的實現:

具體思路：

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

2. 圖片的自動切換: 可使用Timer或者ScheduledExecutorService,這個有多重方式可以實現.

    同時要切換底部的dots（園點）

3.Handler+Message機制更新UI,這個相信大家都很熟練，不再描述

4. 實現的一些細節:注意本例中的優化：圖片的自動切換啓動了其他的線程，要在Activity在可見到不可見的狀態,也就是在onStop()方法中將線程停止，在onStart()方法中開啓線程。否則，Timer沒有停止，或者反覆開啓，會引起較大的內存消耗，時間一長就程序就會崩掉。 還有，就是在跳轉到其他Activity的過程中會出現畫面的卡頓

下面看一下效果圖和具體代碼:

            

工程結構如下圖所示：

main.xml:

然後是具體的佈局文件及代碼實現:

main.xml:

<?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="優酷客戶端" 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="中國家庭院校園區域名字體現" 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:

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;

/**
 * 仿優酷Android客戶端圖片左右滑動
 *
 */
public class MyViewPagerActivity extends Activity {
    private ViewPager viewPager; // android-support-v4中的滑動組件
    private List<ImageView> imageViews; // 滑動的圖片集合

    private String[] titles; // 圖片標題
    private int[] imageResId; // 圖片ID
    private List<View> dots; // 圖片標題正文的那些點

    private TextView tv_title;
    private int currentItem = 0; // 當前圖片的索引號

    // An ExecutorService that can schedule commands to run after a given delay,
    // or to execute periodically.
    private ScheduledExecutorService scheduledExecutorService;

    // 切換當前顯示的圖片
    private Handler handler = new Handler() {
        public void handleMessage(android.os.Message msg) {
            viewPager.setCurrentItem(currentItem);// 切換當前顯示的圖片
        };
    };

    @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] = "鞏俐不低俗，我就不能低俗";
        titles[1] = "撲樹又回來啦！再唱經典老歌引萬人大合唱";
        titles[2] = "揭祕北京電影如何升級";
        titles[3] = "樂視網TV版大派送";
        titles[4] = "熱血屌絲的反殺";

        imageViews = new ArrayList<ImageView>();

        // 初始化圖片資源
        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());// 設置填充ViewPager頁面的適配器
        // 設置一個監聽器，當ViewPager中的頁面改變時調用
        viewPager.setOnPageChangeListener(new MyPageChangeListener());

    }

    @Override
    protected void onStart() {
        scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
        // 當Activity顯示出來後，每兩秒鐘切換一次圖片顯示
        scheduledExecutorService.scheduleAtFixedRate(new ScrollTask(), 1, 2, TimeUnit.SECONDS);
        super.onStart();
    }

    @Override
    protected void onStop() {
        // 當Activity不可見的時候停止切換
        scheduledExecutorService.shutdown();
        super.onStop();
    }

    /**
     * 換行切換任務
     *
     * @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(); // 通過Handler切換圖片
            }
        }

    }

    /**
     * 當ViewPager中頁面的狀態發生改變時調用
     *
     * @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頁面的適配器
     *
     * @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目錄下
btn_back_selector.xml:

<?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:

<?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:

<?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:

<?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:

<?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>

源碼下載地址:

http://download.csdn.net/detail/t12x3456/4751688