ViewPager + Fragment实现滑动标签页

ViewPager 结合Fragment实现一个Activity里包含多个可滑动的标签页，每个标签页可以有独立的布局及响应。

activity_main.xml

MainActivity.java

package com.example.viewpagernfragment;

import java.util.ArrayList;

import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.DisplayMetrics;
import android.view.Menu;
import android.view.View;
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 mPager;
	private ArrayList fragmentList;
	private ImageView image;
	private TextView view1, view2, view3, view4;
	private int currIndex;//当前页卡编号
	private int bmpW;//横线图片宽度
	private int offset;//图片移动的偏移量

	
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		InitTextView();
		InitImage();
		InitViewPager();
	}
	
	
	/*
	 * 初始化标签名
	 */
	public void InitTextView(){
		view1 = (TextView)findViewById(R.id.tv_guid1);
		view2 = (TextView)findViewById(R.id.tv_guid2);
		view3 = (TextView)findViewById(R.id.tv_guid3);
		view4 = (TextView)findViewById(R.id.tv_guid4);
		
		view1.setOnClickListener(new txListener(0));
		view2.setOnClickListener(new txListener(1));
		view3.setOnClickListener(new txListener(2));
		view4.setOnClickListener(new txListener(3));
	}
	
	
	public class txListener implements View.OnClickListener{
		private int index=0;
		
		public txListener(int i) {
			index =i;
		}
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			mPager.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.cursor).getWidth();
		DisplayMetrics dm = new DisplayMetrics();
		getWindowManager().getDefaultDisplay().getMetrics(dm);
		int screenW = dm.widthPixels;
		offset = (screenW/4 - bmpW)/2;
		
		//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);
	}
	
	/*
	 * 初始化ViewPager
	 */
	public void InitViewPager(){
		mPager = (ViewPager)findViewById(R.id.viewpager);
		fragmentList = new ArrayList();
		Fragment btFragment= new ButtonFragment();
		Fragment secondFragment = TestFragment.newInstance("this is second fragment");
		Fragment thirdFragment = TestFragment.newInstance("this is third fragment");
		Fragment fourthFragment = TestFragment.newInstance("this is fourth fragment");
		fragmentList.add(btFragment);
		fragmentList.add(secondFragment);
		fragmentList.add(thirdFragment);
		fragmentList.add(fourthFragment);
		
		//给ViewPager设置适配器
		mPager.setAdapter(new MyFragmentPagerAdapter(getSupportFragmentManager(), fragmentList));
		mPager.setCurrentItem(0);//设置当前显示标签页为第一页
		mPager.setOnPageChangeListener(new MyOnPageChangeListener());//页面变化时的监听器
	}

	
	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) {
			// TODO Auto-generated method stub
			
		}
		
		@Override
		public void onPageScrollStateChanged(int arg0) {
			// TODO Auto-generated method stub
			
		}
		
		@Override
		public void onPageSelected(int arg0) {
			// TODO Auto-generated method stub
			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();
		}
	}
	
	
	@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;
	}

}

谷歌官方认为，ViewPager应该和Fragment一起使用时，此时ViewPager的适配器是FragmentPagerAdapter，当你实现一个FragmentPagerAdapter,你必须至少覆盖以下方法:

getCount()

getItem()

如果ViewPager没有和Fragment一起，ViewPager的适配器是PagerAdapter，它是基类提供适配器来填充页面ViewPager内部，当你实现一个PagerAdapter,你必须至少覆盖以下方法:

• instantiateItem(ViewGroup, int)
• destroyItem(ViewGroup, int, Object)
• getCount()
• isViewFromObject(View, Object)

package com.example.viewpagernfragment;

import java.util.ArrayList;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

public class MyFragmentPagerAdapter extends FragmentPagerAdapter{
	ArrayList list;
	public MyFragmentPagerAdapter(FragmentManager fm,ArrayList list) {
		super(fm);
		this.list = list;
		
	}
	
	
	@Override
	public int getCount() {
		return list.size();
	}
	
	@Override
	public Fragment getItem(int arg0) {
		return list.get(arg0);
	}
	
	
	
	
}

package com.example.viewpagernfragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

public class ButtonFragment extends Fragment{
	Button myButton;
	
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View rootView = inflater.inflate(R.layout.guide_1, container, false);//关联布局文件
		
		myButton = (Button)rootView.findViewById(R.id.mybutton);//根据rootView找到button
		
		//设置按键监听事件
		myButton.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Toast.makeText(ButtonFragment.this.getActivity(), "button is click!", Toast.LENGTH_SHORT).show();
			}
		});
		
		
		return rootView;
	}
}

package com.example.viewpagernfragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class TestFragment extends Fragment {
    private static final String TAG = "TestFragment";
    private String hello;// = "hello android";
    private String defaultHello = "default value";

    static TestFragment newInstance(String s) {
        TestFragment newFragment = new TestFragment();
        Bundle bundle = new Bundle();
        bundle.putString("hello", s);
        newFragment.setArguments(bundle);
        
        //bundle还可以在每个标签里传送数据
        
        
        return newFragment;

    }



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        Log.d(TAG, "TestFragment-----onCreateView");
        Bundle args = getArguments();
        hello = args != null ? args.getString("hello") : defaultHello;
        View view = inflater.inflate(R.layout.guide_2, container, false);
        TextView viewhello = (TextView) view.findViewById(R.id.tv);
        viewhello.setText(hello);
        return view;

    }

   

}