Android菜鸟的成长笔记（27）——ViewPager的使用-白红宇

ViewPager是Android 3.0以上能够使用的API。

一、ViewPager能干什么？

1、微信5.0中连带滑动用ViewPager能够轻松实现。

2、实现相似于新浪微博的导航引导界面。

3、实现其它导航或菜单。

二、ViewPager的使用

1、加入布局

2、载入要显示的布局文件（View）

LayoutInflater lf = getLayoutInflater().from(this);        view1 = lf.inflate(R.layout.layout_0, null);        view2 = lf.inflate(R.layout.layout_1, null);        view3 = lf.inflate(R.layout.layout_2, null);

3、创建View集合

mListViews = new ArrayList
    
     ();        mListViews.add(view1);        mListViews.add(view2);        mListViews.add(view3);

4、创建PagerAdapter

ViewPager的适配器是PagerAdapter，要实现PagerAdapter至少要实现以下方法：

（1）instantiateItem(ViewGroup, int) //加入

（2）destroyItem(ViewGroup, int, Object) //删除

（3）getCount()

（4）isViewFromObject(View, Object)

private class MyPageAdapter extends PagerAdapter {    	private List
    
      mListViews;    	    	public MyPageAdapter(List
     
       mListViews) {			this.mListViews = mListViews;		}    	    	/**    	 * 删除页卡    	 */    	@Override    	public void destroyItem(View container, int position, Object object) {    		((ViewPager) container).removeView(mListViews.get(position));    	}    	    	    	/**    	 * 实例化页卡    	 */    	@Override    	public Object instantiateItem(View container, int position) {    		((ViewPager)container).addView(mListViews.get(position));    		return mListViews.get(position);    	}    	    	/**    	 * 返回页卡的数量    	 */		@Override		public int getCount() {			return mListViews.size();		}		@Override		public boolean isViewFromObject(View arg0, Object arg1) {			return arg0 == arg1; //官方提示这样写		}    	    }

5、配置适配器

mViewPager.setAdapter(new MyPageAdapter(mListViews));

所有代码例如以下：

package com.example.viewpagetest;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.view.LayoutInflater;import android.view.View;public class MainActivity extends Activity {	private List
    
      mListViews;	private View view1;	private View view2;	private View view3;	private ViewPager mViewPager;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                mViewPager = (ViewPager) findViewById(R.id.viewpager);                //载入要显示的选项卡        LayoutInflater lf = getLayoutInflater().from(this);        view1 = lf.inflate(R.layout.layout_0, null);        view2 = lf.inflate(R.layout.layout_1, null);        view3 = lf.inflate(R.layout.layout_2, null);              mListViews = new ArrayList
     
      ();        mListViews.add(view1);        mListViews.add(view2);        mListViews.add(view3);                mViewPager.setAdapter(new MyPageAdapter(mListViews));            }        private class MyPageAdapter extends PagerAdapter {    	private List
      
        mListViews;    	    	public MyPageAdapter(List
       
         mListViews) {			this.mListViews = mListViews;		}    	    	/**    	 * 删除页卡    	 */    	@Override    	public void destroyItem(View container, int position, Object object) {    		((ViewPager) container).removeView(mListViews.get(position));    	}    	    	    	/**    	 * 实例化页卡    	 */    	@Override    	public Object instantiateItem(View container, int position) {    		((ViewPager)container).addView(mListViews.get(position));    		return mListViews.get(position);    	}    	    	/**    	 * 返回页卡的数量    	 */		@Override		public int getCount() {			return mListViews.size();		}		@Override		public boolean isViewFromObject(View arg0, Object arg1) {			return arg0 == arg1; //官方提示这样写		}    	    }}

各个页面代码：

执行效果：

三、实现微信的菜单联动

android.support.v4.view包中的接口和类例如以下：

从上面图片中我们能够看到PagerTabStrip和PagerTitleStrip

从字面意思上理解，PagerTabStrip是能够点击的导航选项卡，而PagerTitleStrip是不能互动的（点击）的导航选项卡。

以下我们改动布局文件例如以下：

layout_gravity能够设置Tab的位置

改动MainActvity

mTitleList = new ArrayList
    
     ();        mTitleList.add("聊天");        mTitleList.add("发现");        mTitleList.add("通讯录");

在PagerAdapter中加入以下代码：

@Overridepublic CharSequence getPageTitle(int position) {	return mTitleList.get(position);}

贴出所有代码，例如以下：

package com.example.viewpagetest;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.view.LayoutInflater;import android.view.View;public class MainActivity extends Activity {	private List
    
      mTitleList;	private List
     
       mListViews;   	private ViewPager mViewPager;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                mViewPager = (ViewPager) findViewById(R.id.viewpager);                //载入要显示的选项卡        LayoutInflater lf = getLayoutInflater().from(this);        View view1 = lf.inflate(R.layout.layout_0, null);        View view2 = lf.inflate(R.layout.layout_1, null);        View view3 = lf.inflate(R.layout.layout_2, null);              mListViews = new ArrayList
      
       ();        mListViews.add(view1);        mListViews.add(view2);        mListViews.add(view3);                mTitleList = new ArrayList
       
        ();        mTitleList.add("聊天");        mTitleList.add("发现");        mTitleList.add("通讯录");                        mViewPager.setAdapter(new MyPageAdapter(mListViews));            }        private class MyPageAdapter extends PagerAdapter {    	private List
        
          mListViews;    	    	public MyPageAdapter(List
         
           mListViews) { this.mListViews = mListViews; } /** * 删除页卡 */ @Override public void destroyItem(View container, int position, Object object) { ((ViewPager) container).removeView(mListViews.get(position)); } /** * 实例化页卡 */ @Override public Object instantiateItem(View container, int position) { ((ViewPager)container).addView(mListViews.get(position)); return mListViews.get(position); } /** * 返回页卡的数量 */ @Override public int getCount() { return mListViews.size(); } @Override public boolean isViewFromObject(View arg0, Object arg1) { return arg0 == arg1; //官方提示这样写 } /** * 设置Tab */ @Override public CharSequence getPageTitle(int position) { return mTitleList.get(position); } }}

执行效果：

上面尽管有了Tab，并能随着页面的切换改变，可是这个并非我们要达到的效果。以下我们自己做一个静态的Tab底部和一个动画来实现。

package com.example.wuye001;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.graphics.BitmapFactory;import android.graphics.Matrix;import android.os.Bundle;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.support.v4.view.ViewPager.OnPageChangeListener;import android.util.DisplayMetrics;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.view.animation.Animation;import android.view.animation.TranslateAnimation;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity {	private ViewPager viewPager;//页卡内容	private ImageView imageView;// 动绘图片	private TextView textView1,textView2,textView3;	private List
    
      views;// Tab页面列表	private int offset = 0;// 动绘图片偏移量	private int currIndex = 0;// 当前页卡编号	private int bmpW;// 动绘图片宽度	private View view1,view2,view3;//各个页卡	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		InitImageView();		InitTextView();		InitViewPager();	}	private void InitViewPager() {		viewPager=(ViewPager) findViewById(R.id.vPager);		views=new ArrayList
     
      ();		LayoutInflater inflater=getLayoutInflater();		view1=inflater.inflate(R.layout.layout_0, null);		view2=inflater.inflate(R.layout.layout_1, null);		view3=inflater.inflate(R.layout.layout_2, null);		views.add(view1);		views.add(view2);		views.add(view3);		viewPager.setAdapter(new MyViewPagerAdapter(views));		viewPager.setCurrentItem(0);		viewPager.setOnPageChangeListener(new MyOnPageChangeListener());	}	 /**	  *  初始化头标	  */	private void InitTextView() {		textView1 = (TextView) findViewById(R.id.text1);		textView2 = (TextView) findViewById(R.id.text2);		textView3 = (TextView) findViewById(R.id.text3);		textView1.setOnClickListener(new MyOnClickListener(0));		textView2.setOnClickListener(new MyOnClickListener(1));		textView3.setOnClickListener(new MyOnClickListener(2));	}	/**	 * 初始化动画，这个就是页卡滑动时。以下的横线也滑动的效果，在这里须要计算一些数据	 */	private void InitImageView() {		imageView= (ImageView) findViewById(R.id.cursor);		bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.a).getWidth();// 获取图片宽度		DisplayMetrics dm = new DisplayMetrics();		getWindowManager().getDefaultDisplay().getMetrics(dm);		int screenW = dm.widthPixels;// 获取分辨率宽度		offset = (screenW / 3 - bmpW) / 2;// 计算偏移量		Matrix matrix = new Matrix();		matrix.postTranslate(offset, 0);		imageView.setImageMatrix(matrix);// 设置动画初始位置	}	/** 	 *     	 * 头标点击监听 3 */	private class MyOnClickListener implements OnClickListener{        private int index=0;        public MyOnClickListener(int i){        	index=i;        }		public void onClick(View v) {			viewPager.setCurrentItem(index);					}			}		public class MyViewPagerAdapter extends PagerAdapter{		private List
      
        mListViews;				public MyViewPagerAdapter(List
       
         mListViews) {			this.mListViews = mListViews;		}		@Override		public void destroyItem(ViewGroup container, int position, Object object) 	{				container.removeView(mListViews.get(position));		}		@Override		public Object instantiateItem(ViewGroup container, int position) {						 container.addView(mListViews.get(position), 0);			 return mListViews.get(position);		}		@Override		public int getCount() {						return  mListViews.size();		}				@Override		public boolean isViewFromObject(View arg0, Object arg1) {						return arg0==arg1;		}	}    public class MyOnPageChangeListener implements OnPageChangeListener{    	int one = offset * 2 + bmpW;// 页卡1 -> 页卡2 偏移量		int two = one * 2;// 页卡1 -> 页卡3 偏移量		public void onPageScrollStateChanged(int arg0) {								}		public void onPageScrolled(int arg0, float arg1, int arg2) {								}		public void onPageSelected(int arg0) {			/*两种方法。这个是一种，以下另一种。显然这个比較麻烦			Animation animation = null;			switch (arg0) {			case 0:				if (currIndex == 1) {					animation = new TranslateAnimation(one, 0, 0, 0);				} else if (currIndex == 2) {					animation = new TranslateAnimation(two, 0, 0, 0);				}				break;			case 1:				if (currIndex == 0) {					animation = new TranslateAnimation(offset, one, 0, 0);				} else if (currIndex == 2) {					animation = new TranslateAnimation(two, one, 0, 0);				}				break;			case 2:				if (currIndex == 0) {					animation = new TranslateAnimation(offset, two, 0, 0);				} else if (currIndex == 1) {					animation = new TranslateAnimation(one, two, 0, 0);				}				break;							}			*/			Animation animation = new TranslateAnimation(one*currIndex, one*arg0, 0, 0);//显然这个比較简洁，仅仅有一行代码。

currIndex = arg0; animation.setFillAfter(true);// True:图片停在动画结束位置 animation.setDuration(300); imageView.startAnimation(animation); } } }

执行效果：

本文转自mfrbuaa博客园博客，原文链接：http://www.cnblogs.com/mfrbuaa/p/5094697.html，如需转载请自行联系原作者