本文實例講述了Android開發實現高仿優酷的客戶端圖片左右滑動切換功能。分享給大家供大家參考,具體如下:
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:圖片的自動切換啟動了其他的線程,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()方法中開啟線程。否則,Timer沒有停止,或者反復開啟,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:
	
然后是具體的布局文件及代碼實現:
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] = "揭秘北京電影如何升級";    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顯示出來后,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>
完整源碼點擊此處本站下載。
希望本文所述對大家Android程序設計有所幫助。
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