• 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:

     

    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" >
    
        <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:

    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:

     
    <?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>
    

    源码下载地址:

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

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  • 原文地址:https://www.cnblogs.com/navy-wang/p/3275347.html
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