使用ViewPager+Fragment实现选项卡切换效果

实现效果

本实例主要实现用ViewPage和Fragment实现选项卡切换效果，选项卡个数为3个，点击选项卡或滑动屏幕会切换Fragment并实现选项卡下方下边框条跟随移动效果。

本程序用android4.2.2真机调试，为方便部署，我使用adbWireless做为部署工具，电脑和手机接入同一局域网，在PC端输入名称adb connect 手机端ip 默认连接5555端口。之后再Eclipse的Devices中即可看到介入设备。前提是android系统需要Root。如下图：

设计实现

• 创建项目（此过程不做赘述）
  

• 在activity_main.xml中设置布局。xml内容如下：

  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:orientation="vertical"
      tools:context="com.example.fengzhengapp.MainActivity" >
      <LinearLayout
          android:layout_width="match_parent"
          android:layout_height="48dp"
          android:orientation="horizontal" >
          <TextView
              android:id="@+id/tv_hot"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:layout_weight="1.0"
              android:background="#ffEAEAEA"
              android:gravity="center"
              android:text="@string/tab_hot"
              android:textSize="18sp" />
          <TextView
              android:id="@+id/tv_news"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:layout_weight="1.0"
              android:background="#ffEAEAEA"
              android:gravity="center"
              android:text="@string/tab_news"
              android:textSize="18sp" />
          <TextView
              android:id="@+id/tv_fav"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:layout_weight="1.0"
              android:background="#ffEAEAEA"
              android:gravity="center"
              android:text="@string/tab_favorite"
              android:textSize="18sp" />
      </LinearLayout>
      <ImageView
          android:id="@+id/cursor"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:scaleType="matrix"
          android:src="@drawable/bgborder" />
      <android.support.v4.view.ViewPager
          android:id="@+id/myViewPager"
          android:layout_width="match_parent"
          android:layout_height="0dp"
          android:layout_weight="1"
          android:flipInterval="30" >
      </android.support.v4.view.ViewPager>
  </LinearLayout>

  上面布局页实现的效果如下：
  

• 接下来，增加3个Fragment布局页 ，分别在里面填充简单的内容
  第一个：

  <?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" >
      <TextView
          android:id="@+id/txtHot"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:layout_weight="1"
          android:text="this is the hot tab" >
      </TextView>
  </LinearLayout>

  第二个：

  <?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" >
      <TextView
          android:id="@+id/txtNews"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:layout_weight="1"
          android:text="this is the news tab" >
      </TextView>
  </LinearLayout>

  第三个:

  <?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" >
      <TextView
          android:id="@+id/txtFav"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:layout_weight="1"
          android:text="this is the Fav tab" >
      </TextView>
  </LinearLayout>

  以上3个Fragment的布局文件已创建完毕，每个文件中只显示简单的文本内容，用做演示。
  

• 加载3个Fragment到Activity中。

首先实现3个Fragment对应的后台类

热点布局页对应的类：

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class FragmentHot extends Fragment {
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View view = inflater.inflate(R.layout.fragmenthot, container, false);
		return view;
	}
}

news布局页对应的类：

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class FragmentNews extends Fragment {
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View view = inflater.inflate(R.layout.fragmentnews, container, false);
		return view;
	}
}

收藏布局页对应的类：

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class FragmentFavorite extends Fragment {
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View view = inflater.inflate(R.layout.fragmentfav, container, false);
		return view;
	}
}

• 之后再activity中初始化这3个Fragment

  注意要点：
  Activity继承自FragmentActivity
  要实现一个FragmentPagerAdapter，内容如下：

  import java.util.ArrayList;
  import android.support.v4.app.Fragment;
  import android.support.v4.app.FragmentManager;
  import android.support.v4.app.FragmentPagerAdapter;
  public class MyFragmentAdapter extends FragmentPagerAdapter {
  	ArrayList<Fragment> list;
  	public MyFragmentAdapter(FragmentManager fm,ArrayList<Fragment> list){
  		super(fm);
  		this.list = list;
  	}
  	@Override
  	public Fragment getItem(int arg0) {
  		// TODO Auto-generated method stub
  		return list.get(arg0);
  	}
  	@Override
  	public int getCount() {
  		// TODO Auto-generated method stub
  		return list.size();
  	}
  }

  然后在Activity中实现切换和动画效果，代码如下：

  import java.util.ArrayList;
  import android.app.Activity;
  import android.graphics.BitmapFactory;
  import android.graphics.Matrix;
  import android.os.Bundle;
  import android.support.v4.app.Fragment;
  import android.support.v4.view.ViewPager;
  import android.support.v4.view.ViewPager.OnPageChangeListener;
  import android.util.DisplayMetrics;
  import android.util.Log;
  import android.view.Menu;
  import android.view.View;
  import android.support.v4.app.FragmentActivity;
  import android.view.MenuItem;
  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 FragmentActivity {
  	private ViewPager mViewPager;
  	private ArrayList fragments;
  	private TextView view1, view2, view3;  
      private int currIndex;
      private ImageView image;
      private static int bmpW;//横线图片宽度  
      private static int offset;//图片移动的偏移量  
  	@Override
  	protected void onCreate(Bundle savedInstanceState) {
  		super.onCreate(savedInstanceState);
  		setContentView(R.layout.activity_main);
  		initViewPager();
  		InitTextView();
  		InitImage();
  	}
  	@Override
  	public boolean onCreateOptionsMenu(Menu menu) {
  		// Inflate the menu; this adds items to the action bar if it is present.
  		getMenuInflater().inflate(R.menu.main, menu);
  		return true;
  	}
  	@Override
  	public boolean onOptionsItemSelected(MenuItem item) {
  		// Handle action bar item clicks here. The action bar will
  		// automatically handle clicks on the Home/Up button, so long
  		// as you specify a parent activity in AndroidManifest.xml.
  		int id = item.getItemId();
  		if (id == R.id.action_settings) {
  			return true;
  		}
  		return super.onOptionsItemSelected(item);
  	}
  	private void InitTextView(){
  		view1 = (TextView) findViewById(R.id.tv_hot);
  		view2 = (TextView) findViewById(R.id.tv_news);
  		view3 = (TextView) findViewById(R.id.tv_fav);
  		view1.setOnClickListener(new txtListener(0));
  		view2.setOnClickListener(new txtListener(1));
  		view3.setOnClickListener(new txtListener(2));
  	}
  	//内部类 重写TextView点击事件
  	public class txtListener implements View.OnClickListener{
  		private int index = 0;
  		public txtListener(int i){
  			index = i;
  		}
  		@Override
  		public void onClick(View v){
  			mViewPager.setCurrentItem(index);
  		}
  	}
  	/* 
   * 初始化图片的位移像素 
   */  
  public void InitImage(){  
      image = (ImageView)findViewById(R.id.cursor);  
      bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.bgborder).getWidth();  
      DisplayMetrics dm = new DisplayMetrics();  
      getWindowManager().getDefaultDisplay().getMetrics(dm);  
      int screenW = dm.widthPixels;  
      offset = (screenW/3 - bmpW)/2;  
      Log.i("screenW",String.valueOf(screenW));
      Log.i("bmpW",String.valueOf(bmpW));
      Log.i("offset",String.valueOf(offset));
      //imgageview设置平移，使下划线平移到初始位置（平移一个offset）  
      Matrix matrix = new Matrix();  
      matrix.postTranslate(offset, 0);  
      image.setImageMatrix(matrix);  
  }  
  private void initViewPager(){
  	mViewPager = (ViewPager)findViewById(R.id.myViewPager);
  	fragments = new ArrayList<Fragment>();
  	Fragment fragmentHot = new FragmentHot();
  	Fragment fragmentNews = new FragmentNews();
  	Fragment fragmentFav = new FragmentFavorite();
  	fragments.add(fragmentHot);
  	fragments.add(fragmentNews);
  	fragments.add(fragmentFav);
  	mViewPager.setAdapter(new MyFragmentAdapter(getSupportFragmentManager(), fragments));
  	mViewPager.setCurrentItem(0);
  	mViewPager.setOnPageChangeListener(new myOnPageChangeListener());
  }
  public class myOnPageChangeListener implements OnPageChangeListener {
  	private int one = offset*2 +bmpW;//两个相邻页面的偏移量   
  	@Override
  	public void onPageScrolled(int arg0, float arg1, int arg2) {
  	}
  	@Override
  	public void onPageScrollStateChanged(int arg0) {
  		// TODO Auto-generated method stub
  	}
  	@Override  
      public void onPageSelected(int arg0) {  
          // TODO Auto-generated method stub  
  		Log.i("aaaaaaaaaaaaa",String.valueOf(arg0));
  		Log.i("one",String.valueOf(one));
          Animation animation = new TranslateAnimation(currIndex*one,arg0*one,0,0);//平移动画  
          currIndex = arg0; 
          animation.setFillAfter(true);//动画终止时停留在最后一帧，不然会回到没有执行前的状态  
          animation.setDuration(200);//动画持续时间0.2秒  
          image.startAnimation(animation);//是用ImageView来显示动画的  
          //int i = currIndex + 1;  
         // Toast.makeText(MainActivity.this, "您选择了第"+i+"个页卡", Toast.LENGTH_SHORT).show();  
      }  
  }  
  }

  源代码地址请访问这里：源码