ViewPager（二）：Fragment+ViewPager实现页面滑动

效果图：



功能：点击标题栏可以切换页面，滑动可切换页面。

activity_main.xml布局文件代码：

<LinearLayout
android:id="@+id/layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">

<TextView
android:id="@+id/news"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="新闻"
android:textSize="20sp"
android:gravity="center"
android:clickable="true"/>

<TextView
android:id="@+id/sport"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="体育"
android:textSize="20sp"
android:gravity="center"
android:clickable="true"/>
<TextView
android:id="@+id/entertainment"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="娱乐"
android:textSize="20sp"
android:gravity="center"
android:clickable="true"/>
<TextView
android:id="@+id/weather"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="天气"
android:textSize="20sp"
android:gravity="center"
android:clickable="true"/>
</LinearLayout>
<android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/layout"
></android.support.v4.view.ViewPager>
fragment的布局文件fragment.xml中就存放了一个TextView
MainActivity.java的代码如下：

import java.util.ArrayList;
import java.util.List;

import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.LinearLayout;
import android.widget.TextView;

//要继承v4包的FragmentActivity
public class MainActivity extends FragmentActivity {
private ViewPager viewPager;
private List<Fragment> fragments; //集合存储每个页面的fragment
private TextView[] titles;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager=(ViewPager)findViewById(R.id.viewPager);
//创建集合，初始化页面的Fragment
initFragment();

MyAdapter adapter = new MyAdapter(getSupportFragmentManager());
viewPager.setAdapter(adapter);

//初始化标题
initTitle();
viewPager.setOnPageChangeListener(new OnPageChangeListener() {

@Override
public void onPageSelected(int arg0) {
// TODO Auto-generated method stub
for (int i = 0; i < titles.length; i++) {
titles[i].setBackgroundColor(Color.WHITE);
}
titles[arg0].setBackgroundColor(Color.GRAY);

}

@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

}
});
}

private void initTitle() {
// TODO Auto-generated method stub
titles=new TextView[fragments.size()];
LinearLayout layout = (LinearLayout)findViewById(R.id.layout);
for (int i = 0; i < titles.length; i++) {
titles[i]=(TextView) layout.getChildAt(i);
titles[i].setBackgroundColor(Color.WHITE);
titles[i].setTag(i);
titles[i].setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
viewPager.setCurrentItem((Integer)v.getTag());

}
});
}
//第一个默认选中
titles[0].setBackgroundColor(Color.GRAY);
}

//PagerAdapter适用于view,
//如果ViewPager加载Fragment，使用FragmentPagerAdapter
class MyAdapter extends FragmentPagerAdapter{

public MyAdapter(FragmentManager fm) {
super(fm);
// TODO Auto-generated constructor stub
}

@Override
public Fragment getItem(int arg0) {
// TODO Auto-generated method stub
return fragments.get(arg0);
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return fragments.size();
}

}

private void initFragment() {
// TODO Auto-generated method stub
fragments=new ArrayList<Fragment>();

//新闻
MyFragment mf1=new MyFragment();
Bundle bundle = new Bundle();
bundle.putInt("tabIndex", 0);
mf1.setArguments(bundle);
fragments.add(mf1);
//体育
MyFragment mf2=new MyFragment();
bundle = new Bundle();
bundle.putInt("tabIndex", 1);
mf2.setArguments(bundle);
fragments.add(mf2);
//娱乐
MyFragment mf3=new MyFragment();
bundle = new Bundle();
bundle.putInt("tabIndex", 2);
mf3.setArguments(bundle);
fragments.add(mf3);
//天气
MyFragment mf4=new MyFragment();
bundle = new Bundle();
bundle.putInt("tabIndex", 3);
mf4.setArguments(bundle);
fragments.add(mf4);

}

}


MyFragment.java的代码如下：
import android.graphics.Color;
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.TextView;

public class MyFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment, null);
TextView tv=(TextView)view.findViewById(R.id.tv);

Bundle bundle = getArguments();
int tabIndex=bundle.getInt("tabIndex");
switch (tabIndex) {
case 0:
tv.setText("刘云山访问朝鲜");
view.setBackgroundColor(Color.BLUE);
break;
case 1:
tv.setText("尼克斯获胜");
view.setBackgroundColor(Color.RED);
break;
case 2:
tv.setText("呼叫大黑牛");
view.setBackgroundColor(Color.GREEN);
break;
case 3:
tv.setText("今天天气好晴朗");
view.setBackgroundColor(Color.YELLOW);
break;

default:
break;
}
return view;
}
}