ViewPager是Android 3.0以上可以使用的API。
一、ViewPager能干什么?
1、微信5.0中连带滑动用ViewPager可以轻松实现。
2、实现类似于新浪微博的导航引导界面。
3、实现其他导航或菜单。
二、ViewPager的使用
1、添加布局
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <android.support.v4.view.ViewPager android:id="@+id/viewpager" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center"/> </LinearLayout>2、加载要显示的布局文件(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<View>(); 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) //添加
(2)destroyItem(ViewGroup, int, Object) //删除
(3)getCount()
(4)isViewFromObject(View, Object)
private class MyPageAdapter extends PagerAdapter { private List<View> mListViews; public MyPageAdapter(List<View> 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));
全部代码如下:
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<View> 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); //加载要显示的选项卡 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<View>(); mListViews.add(view1); mListViews.add(view2); mListViews.add(view3); mViewPager.setAdapter(new MyPageAdapter(mListViews)); } private class MyPageAdapter extends PagerAdapter { private List<View> mListViews; public MyPageAdapter(List<View> 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:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:text="1" android:gravity="center" android:textSize="120sp" android:textColor="#33b5e5" /> </LinearLayout>运行效果: