Android应用中利用ViewPager实现多页面滑动切换效果示例

2020-01-02 06:59:04

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1、添加android support包
因为上面的几个类都是在android support包中才提供，我们先添加包。
在Eclipse->Window->Android SDK Manager，选择列表中Extras->Android Support Library进行安装。下载完后在android-sdk/extras/android/support目录下，这里我们选择v4版本，进入v4目录，拷贝其中的android-support-v4.jar文件到工程的libs目录(若没有新建)下即可，编译时ADT会自动将其导入项目中。

2、新建ViewPager的layout，内容如下

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="match_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" >    <android.support.v4.view.PagerTabStrip        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="top" />  </android.support.v4.view.ViewPager></LinearLayout>

ViewPager用来管理layout并可以左右滑动显示各个页面数据，PagerTabStrip用来显示页面title，android:layout_gravity="top"表示title在顶部，可设置bottom等。

3、新建FragmentActivity页面
FragmentActivity页面含有ViewPager元素，可以用来显示Fragment，定义如下：

public class ViewPagerDemo extends FragmentActivity {  /** 页面list **/  List<Fragment> fragmentList = new ArrayList<Fragment>();  /** 页面title list **/  List<String>  titleList  = new ArrayList<String>();  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.view_pager_demo);    ViewPager vp = (ViewPager)findViewById(R.id.viewPager);    fragmentList.add(new ViewPagerFragment1("页面1"));    fragmentList.add(new ViewPagerFragment1("页面2"));    fragmentList.add(new ViewPagerFragment1("页面3"));    titleList.add("title 1 ");    titleList.add("title 2 ");    titleList.add("title 3 ");    vp.setAdapter(new myPagerAdapter(getSupportFragmentManager(), fragmentList, titleList));  }  /**   * 定义适配器   */  class myPagerAdapter extends FragmentPagerAdapter {    private List<Fragment> fragmentList;    private List<String>  titleList;    public myPagerAdapter(FragmentManager fm, List<Fragment> fragmentList, List<String> titleList){      super(fm);      this.fragmentList = fragmentList;      this.titleList = titleList;    }    /**     * 得到每个页面     */    @Override    public Fragment getItem(int arg0) {      return (fragmentList == null || fragmentList.size() == 0) ? null : fragmentList.get(arg0);    }    /**     * 每个页面的title     */    @Override    public CharSequence getPageTitle(int position) {      return (titleList.size() > position) ? titleList.get(position) : "";    }    /**     * 页面的总个数     */    @Override    public int getCount() {      return fragmentList == null ? 0 : fragmentList.size();    }  }}

其中的myPagerAdapter集成自ragmentPagerAdapter，为ViewPager提供数据源。

onCreate函数得到ViewPager实例并设置数据源，getSupportFragmentManager表示得到Fragment管理器。ViewPagerFragment1表示具体的页面，见下面介绍。

4、新建Fragment页面
Fragment页面即为左右滑动需要显示的页面，新建类集成Fragment，并重写onCreateView函数即可。onCreateView函数相当于Activity的onCreate函数。如下：

public class ViewPagerFragment1 extends Fragment {  private String  text;  private TextView tv = null;  public ViewPagerFragment1(String text){    super();    this.text = text;  }  /**   * 覆盖此函数，先通过inflater inflate函数得到view最后返回   */  @Override  public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {    View v = inflater.inflate(R.layout.view_pager_fragment_demo1, container, false);    tv = (TextView)v.findViewById(R.id.viewPagerText);    tv.setText(text);    return v;  }}

5、示例工程代码：

package cn.trinea.android.demo;import java.util.ArrayList;import java.util.List;import android.os.Bundle;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentPagerAdapter;import android.support.v4.view.ViewPager;public class ViewPagerDemo extends BaseFragmentActivity {  private static int TOTAL_COUNT = 3;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState, R.layout.view_pager_demo);    ViewPager vp = (ViewPager)findViewById(R.id.view_pager);    List<Fragment> fragmentList = new ArrayList<Fragment>();    List<String> titleList = new ArrayList<String>();    for (int i = 0; i < TOTAL_COUNT; i++) {      ViewPagerFragment viewPagerFragment1 = new ViewPagerFragment();      Bundle bundle = new Bundle();      bundle.putInt("upImageId", 0);      bundle.putString("text", "Page " + i);      viewPagerFragment1.setArguments(bundle);      titleList.add("title " + i);      fragmentList.add(viewPagerFragment1);    }    vp.setAdapter(new myPagerAdapter(getSupportFragmentManager(), fragmentList, titleList));  }  class myPagerAdapter extends FragmentPagerAdapter {    private List<Fragment> fragmentList;    private List<String>  titleList;    public myPagerAdapter(FragmentManager fm, List<Fragment> fragmentList, List<String> titleList) {      super(fm);      this.fragmentList = fragmentList;      this.titleList = titleList;    }    @Override    public Fragment getItem(int arg0) {      return (fragmentList == null || fragmentList.size() == 0) ? null : fragmentList.get(arg0);    }    @Override    public CharSequence getPageTitle(int position) {      return (titleList.size() > position) ? titleList.get(position) : "";    }    @Override    public int getCount() {      return fragmentList == null ? 0 : fragmentList.size();    }  }}

简单效果如下：

2016323102800943.jpg (476×204)