ViewPager左右轮滑

Posted 2020-08-22

1. package com.example.viewpagerdemo;  
2.   
3. import android.app.Activity;  
4. import android.os.Bundle;  
5. import android.support.v4.view.PagerAdapter;  
6. import android.support.v4.view.ViewPager;  
7. import android.support.v4.view.ViewPager.OnPageChangeListener;  
8. import android.view.View;  
9. import android.view.ViewGroup;  
10. import android.view.ViewGroup.LayoutParams;  
11. import android.widget.ImageView;  
12. import android.widget.LinearLayout;  
13.   
14. public class TwoActivity extends Activity implements OnPageChangeListener{  
15.     /** 
16.      * ViewPager 
17.      */  
18.     private ViewPager viewPager;  
19.       
20.     /** 
21.      * 装点点的ImageView数组 
22.      */  
23.     private ImageView[] tips;  
24.       
25.     /** 
26.      * 装ImageView数组 
27.      */  
28.     private ImageView[] mImageViews;  
29.       
30.     /** 
31.      * 图片资源id 
32.      */  
33.     private int[] imgIdArray ;  
34.   
35.     @Override  
36.     protected void onCreate(Bundle savedInstanceState) {  
37.         super.onCreate(savedInstanceState);  
38.         setContentView(R.layout.activity_main);  
39.         ViewGroup group = (ViewGroup)findViewById(R.id.viewGroup);  
40.         viewPager = (ViewPager) findViewById(R.id.viewPager);  
41.           
42.         //载入图片资源ID  
43.         imgIdArray = new int[]{R.drawable.item01, R.drawable.item02, R.drawable.item03, R.drawable.item04,  
44.                 R.drawable.item05,R.drawable.item06, R.drawable.item07, R.drawable.item08};  
45.           
46.           
47.         //将点点加入到ViewGroup中  
48.         tips = new ImageView[imgIdArray.length];  
49.         for(int i=0; i<tips.length; i++){  
50.             ImageView imageView = new ImageView(this);  
51.             imageView.setLayoutParams(new LayoutParams(10,10));  
52.             tips[i] = imageView;  
53.             if(i == 0){  
54.                 tips[i].setBackgroundResource(R.drawable.page_indicator_focused);  
55.             }else{  
56.                 tips[i].setBackgroundResource(R.drawable.page_indicator_unfocused);  
57.             }  
58.               
59.             LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT,    
60.                     LayoutParams.WRAP_CONTENT));  
61.             layoutParams.leftMargin = 5;  
62.             layoutParams.rightMargin = 5;  
63.             group.addView(imageView, layoutParams);  
64.         }  
65.           
66.           
67.         //将图片装载到数组中  
68.         mImageViews = new ImageView[imgIdArray.length];  
69.         for(int i=0; i<mImageViews.length; i++){  
70.             ImageView imageView = new ImageView(this);  
71.             mImageViews[i] = imageView;  
72.             imageView.setBackgroundResource(imgIdArray[i]);  
73.         }  
74.           
75.         //设置Adapter  
76.         viewPager.setAdapter(new MyAdapter());  
77.         //设置监听，主要是设置点点的背景  
78.         viewPager.setOnPageChangeListener(this);  
79.         //设置ViewPager的默认项, 设置为长度的100倍，这样子开始就能往左滑动  
80.         viewPager.setCurrentItem((mImageViews.length) * 100);  
81.           
82.     }  
83.       
84.     /** 
85.      *  
86.      * @author xiaanming 
87.      * 
88.      */  
89.     public class MyAdapter extends PagerAdapter{  
90.   
91.         @Override  
92.         public int getCount() {  
93.             return Integer.MAX_VALUE;  
94.         }  
95.   
96.         @Override  
97.         public boolean isViewFromObject(View arg0, Object arg1) {  
98.             return arg0 == arg1;  
99.         }  
100.   
101.         @Override  
102.         public void destroyItem(View container, int position, Object object) {  
103.             ((ViewPager)container).removeView(mImageViews[position % mImageViews.length]);  
104.               
105.         }  
106.   
107.         /** 
108.          * 载入图片进去，用当前的position 除以 图片数组长度取余数是关键 
109.          */  
110.         @Override  
111.         public Object instantiateItem(View container, int position) {  
112.             ((ViewPager)container).addView(mImageViews[position % mImageViews.length], 0);  
113.             return mImageViews[position % mImageViews.length];  
114.         }  
115.           
116.           
117.           
118.     }  
119.   
120.     @Override  
121.     public void onPageScrollStateChanged(int arg0) {  
122.           
123.     }  
124.   
125.     @Override  
126.     public void onPageScrolled(int arg0, float arg1, int arg2) {  
127.           
128.     }  
129.   
130.     @Override  
131.     public void onPageSelected(int arg0) {  
132.         setImageBackground(arg0 % mImageViews.length);  
133.     }  
134.       
135.     /** 
136.      * 设置选中的tip的背景 
137.      * @param selectItems 
138.      */  
139.     private void setImageBackground(int selectItems){  
140.         for(int i=0; i<tips.length; i++){  
141.             if(i == selectItems){  
142.                 tips[i].setBackgroundResource(R.drawable.page_indicator_focused);  
143.             }else{  
144.                 tips[i].setBackgroundResource(R.drawable.page_indicator_unfocused);  
145.             }  
146.         }  
147.     }  
148.   
149. }
153. ViewPageAdapter

154. package com.tree.schoollife.adapter;
     
     import android.support.v4.view.PagerAdapter;
     import android.view.View;
     import android.view.ViewGroup;
     import android.view.ViewParent;
     import android.widget.ImageView;
     
     import java.util.List;
     
     /**
      * Created by tree on 2016/11/10.
      */
     public class ViewPagerAdapter extends PagerAdapter {
     
         private List<ImageView> mData;
     
         public ViewPagerAdapter(List<ImageView> mData) {
             this.mData = mData;
         }
     
         
         @Override
         public int getCount() {
             return Integer.MAX_VALUE;
         }
     
         @Override
         public Object instantiateItem(ViewGroup container, int position) {
             //对ViewPager页号求模取出View列表中要显示的项
             position %= mData.size();
             if (position<0){
                 position = mData.size()+position;
             }
             ImageView view = mData.get(position);
             //如果View已经在之前添加到了一个父组件，则必须先remove，否则会抛出IllegalStateException。
             ViewParent vp =view.getParent();
             if (vp!=null){
                 ViewGroup parent = (ViewGroup)vp;
                 parent.removeView(view);
             }
             container.addView(view);
             //add listeners here if necessary
             return view;
     
     
         }
     
         
         @Override
         public void destroyItem(ViewGroup container, int position, Object object) {
             //Warning：不要在这里调用removeView
         }
     
        
         @Override
         public boolean isViewFromObject(View view, Object object) {
             return view==object;
         }
     
     
     }