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| 一、问题描述 |
双导航tab切换（底部区块+区域内头部导航），实现方案底部区域使用FragmentTabHost+Fragment, 区域内头部导航使用ViewPager+Fragment，可在之前博客Android典型界面设计2（FragmentTabHost+Fragment实现底部tab切换）基础之上和Android典型界面设计1（ViewPage+Fragment实现区域顶部tab滑动切换）整合应用实现。查看两篇博客请点击：http://www.cnblogs.com/jerehedu/p/4607599.html#dxjmsj。效果如图所示：
| 二、案例主要组件 |
1、首先实现底部区块的tab切换，这部分请参考博客：Android典型界面设计2（FragmentTabHost+Fragment实现底部tab切换）
2、底部tab各自对应Fragment组件，共5个Fragment为NewsFragment、ReadFragment、FoundFragment、OwnerFragment、VideoFragment,根据不同板块各自设计界面，接下下来在之前基础上实现NewsFragment界面的设计，该界面实现新闻各个频道之间的切换，即区域内头部导航
先看一下NewsFragment的布局文件：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<RelativeLayout android:layout_width="match_parent"
android:layout_height="wrap_content">
<HorizontalScrollView
android:id="@+id/hvChannel"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toLeftOf="@+id/ivShowChannel"
android:scrollbars="none">
<RadioGroup
android:id="@+id/rgChannel"
android:layout_width="wrap_content"
android:layout_height="wrap_content" android:orientation="horizontal">
</RadioGroup>
</HorizontalScrollView>
<ImageView android:layout_width="40dp"
android:layout_height="40dp"
android:id="@+id/ivShowChannel"
android:layout_alignParentRight="true"
android:src="@drawable/channel_down_narrow"
android:scaleType="fitXY"
/>
</RelativeLayout>
<android.support.v4.view.ViewPager
android:id="@+id/vpNewsList"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
</android.support.v4.view.ViewPager>
</LinearLayout>
NewsFragment代码如下：
public class NewsFragment extends Fragment implements OnPageChangeListener {
private View view=null;
private RadioGroup rgChannel=null;
private ViewPager viewPager;
private HorizontalScrollView hvChannel=null;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if(view==null){
view=inflater.inflate(R.layout.news_fragment_layout, null);
rgChannel=(RadioGroup)view.findViewById(R.id.rgChannel);
viewPager=(ViewPager)view.findViewById(R.id.vpNewsList);
hvChannel=(HorizontalScrollView)view.findViewById(R.id.hvChannel);
rgChannel.setOnCheckedChangeListener(
new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group,
int checkedId) {
viewPager.setCurrentItem(checkedId);
}
});
initTab(inflater);
initViewPager();
}
ViewGroup parent=(ViewGroup)view.getParent();
if(parent!=null){
parent.removeView(view);
}
return view;
}
private List<Fragment> newsChannelList=new ArrayList<Fragment>();
private NewsPageFragmentAdapter adapter;
private void initViewPager(){
List<Channel> channelList=ChannelDb.getSelectedChannel();
for(int i=0;i<channelList.size();i++){
NewsChannelFragment fragment=new NewsChannelFragment();
Bundle bundle=new Bundle();
bundle.putString("cname", channelList.get(i).getName());
fragment.setArguments(bundle);
newsChannelList.add(fragment);
}
adapter=new NewsPageFragmentAdapter(super.getActivity().getSupportFragmentManager(), newsChannelList);
viewPager.setAdapter(adapter);
viewPager.setOffscreenPageLimit(2);
viewPager.setCurrentItem(0);
viewPager.setOnPageChangeListener(this);
}
private void initTab(LayoutInflater inflater){
List<Channel> channelList=ChannelDb.getSelectedChannel();
for(int i=0;i<channelList.size();i++){
RadioButton rb=(RadioButton)inflater.
inflate(R.layout.tab_rb, null);
rb.setId(i);
rb.setText(channelList.get(i).getName());
RadioGroup.LayoutParams params=new
RadioGroup.LayoutParams(RadioGroup.LayoutParams.WRAP_CONTENT,
RadioGroup.LayoutParams.WRAP_CONTENT);
rgChannel.addView(rb,params);
}
rgChannel.check(0);
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageSelected(int idx) {
setTab(idx);
}
private void setTab(int idx){
RadioButton rb=(RadioButton)rgChannel.getChildAt(idx);
rb.setChecked(true);
int left=rb.getLeft();
int width=rb.getMeasuredWidth();
DisplayMetrics metrics=new DisplayMetrics();
super.getActivity().getWindowManager().getDefaultDisplay().getMetrics(metrics);
int screenWidth=metrics.widthPixels;
int len=left+width/2-screenWidth/2;
hvChannel.smoothScrollTo(len, 0);
}
}
3、NewsChannelFragment 组件代码：
public class NewsChannelFragment extends Fragment {
private String channelName;
@Override
public void setArguments(Bundle args) {
channelName=args.getString("cname");
}
@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
}
private TextView view;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if(view==null){
view=new TextView(super.getActivity());
view.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
view.setGravity(Gravity.CENTER);
view.setTextSize(30);
view.setText(channelName);
}
ViewGroup parent=(ViewGroup)view.getParent();
if(parent!=null){
parent.removeView(view);
}
return view;
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
}
}
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原文地址：http://www.cnblogs.com/likeju/p/4700636.html
