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高仿优酷Android客户端图片左右滑动(自动切换)

2012-11-13 09:19 489 查看
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

然后是具体的布局文件及代码实现: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" ><RelativeLayoutandroid:layout_width="fill_parent"android:layout_height="40dip"android:background="@drawable/title_bk" ><ImageButtonandroid: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" /><Viewandroid:id="@+id/line0"android:layout_width="1px"android:layout_height="fill_parent"android:layout_toRightOf="@id/btn_back"android:background="#aa11264f" /><Viewandroid:layout_width="1px"android:layout_height="fill_parent"android:layout_toRightOf="@id/line0"android:background="#009ad6" /><TextViewandroid: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><FrameLayoutandroid:layout_width="fill_parent"android:layout_height="140dip" ><android.support.v4.view.ViewPagerandroid:id="@+id/vp"android:layout_width="fill_parent"android:layout_height="fill_parent" /><LinearLayoutandroid:layout_width="fill_parent"android:layout_height="35dip"android:layout_gravity="bottom"android:background="#33000000"android:gravity="center"android:orientation="vertical" ><TextViewandroid: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" /><LinearLayoutandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginTop="3dip"android:gravity="center" ><Viewandroid:id="@+id/v_dot0"style="@style/dot_style"android:background="@drawable/dot_focused" /><Viewandroid:id="@+id/v_dot1"style="@style/dot_style" /><Viewandroid:id="@+id/v_dot2"style="@style/dot_style" /><Viewandroid:id="@+id/v_dot3"style="@style/dot_style" /><Viewandroid: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IDprivate 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};};@Overridepublic 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());}@Overrideprotected 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();}@Overrideprotected 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 {@Overridepublic int getCount() {return imageResId.length;}@Overridepublic Object instantiateItem(View arg0, int arg1) {((ViewPager) arg0).addView(imageViews.get(arg1));return imageViews.get(arg1);}@Overridepublic void destroyItem(View arg0, int arg1, Object arg2) {((ViewPager) arg0).removeView((View) arg2);}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {return arg0 == arg1;}@Overridepublic void restoreState(Parcelable arg0, ClassLoader arg1) {}@Overridepublic Parcelable saveState() {return null;}@Overridepublic void startUpdate(View arg0) {}@Overridepublic void finishUpdate(View arg0) {}}}


Drawable目录下

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" ><gradientandroid: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>
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