学习Android app 的TAB页面切换

FragmentActivity+ ViewPager + FragmentManager实现

废话少说，直接上我今晚的成果：

package com.itfanr.viewpagertab;

import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.support.v4.app.FragmentTransaction  ;
import android.support.v4.app.FragmentManager;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView.FindListener;
import android.widget.TextView;

public class MainActivity extends FragmentActivity {
private FragmentManager fragmentManager;
private ViewPager viewPager;
private Context context;

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fragmentManager = this.getSupportFragmentManager();		;
this.viewPager = (ViewPager) findViewById(R.id.mainViewPager);
this.viewPager.setAdapter(new MainFragmentAdapter(fragmentManager));
this.viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener(){

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

}

@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub

}

@Override
public void onPageSelected(int arg0) {
FragmentManager fragmentManager = MainActivity.this.fragmentManager ;
List<Fragment> list = fragmentManager.getFragments() ;
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction() ;
fragmentTransaction.show(list.get(arg0)) ;
fragmentTransaction.commit() ;
}

}) ;
}

public static class PlaceholderFragment extends Fragment {
private String text;
private TextView textView;

public PlaceholderFragment(String text) {
this.text = text;
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
return rootView;
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
this.textView = (TextView) getView().findViewById(R.id.textView);
textView.setText(this.text);
}

}

}

package com.itfanr.viewpagertab;

import java.util.ArrayList;
import java.util.List;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentPagerAdapter;

import com.itfanr.viewpagertab.MainActivity.PlaceholderFragment;

public class MainFragmentAdapter extends FragmentPagerAdapter {

private List<Fragment> mainFragment;

public MainFragmentAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
this.mainFragment = new ArrayList<Fragment>();
this.mainFragment.add(new PlaceholderFragment("第一个fragment"));
this.mainFragment.add(new PlaceholderFragment("第二个fragment"));
}

@Override
public Fragment getItem(int arg0) {

return this.mainFragment.get(arg0);
}

@Override
public int getCount() {
return this.mainFragment.size();
}

}

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/mainViewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical"
tools:context=".MainActivity" >

</android.support.v4.view.ViewPager>

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.placeholder.MainActivity$PlaceholderFragment" >

<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>

</RelativeLayout>

后面这两个分别是布局文件activity_main.xml和fragment_main.xml。