利用fragment实现tab选项卡效果：
将radiogroup与fragment集合，实现tab选项卡效果，这里面最关键的几个文件：
1.fragmenttabadapter类：
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/**
*@description:
*@author:nate robinson
*@since:2015-2-12
*/
public class fragmenttabadapter implements radiogroup.oncheckedchangelistener
{
private list<fragment> fragments; // 一个tab页面对应一个fragment
private radiogroup rgs; // 用于切换tab
private activity activity; // fragment所属的activity
private int fragmentcontentid; // activity中所要被替换的区域的id
private int currenttab; // 当前tab页面索引
private onrgsextracheckedchangedlistener onrgsextracheckedchangedlistener; // 用于让调用者在切换tab时候增加新的功能
public fragmenttabadapter(activity activity, list<fragment> fragments, int fragmentcontentid, radiogroup rgs)
{
this.fragments = fragments;
this.rgs = rgs;
this.activity = activity;
this.fragmentcontentid = fragmentcontentid;
// 默认显示第一页
android.app.fragmenttransaction ft = activity.getfragmentmanager().begintransaction();
ft.add(fragmentcontentid, fragments.get(0));
ft.commit();
rgs.setoncheckedchangelistener(this);
}
@override
public void oncheckedchanged(radiogroup radiogroup, int checkedid)
{
for(int i = 0; i < rgs.getchildcount(); i++)
{
if(rgs.getchildat(i).getid() == (checkedid))
{
fragment fragment = fragments.get(i);
fragmenttransaction ft = activity.getfragmentmanager().begintransaction();
getcurrentfragment().onpause(); // 暂停当前tab
// getcurrentfragment().onstop(); // 暂停当前tab
if(fragment.isadded())
{
// fragment.onstart(); // 启动目标tab的onstart()
fragment.onresume(); // 启动目标tab的onresume()
}
else
{
ft.add(fragmentcontentid, fragment);
}
showtab(i); // 显示目标tab
ft.commit();
// 如果设置了切换tab额外功能功能接口
if(null != onrgsextracheckedchangedlistener)
{
onrgsextracheckedchangedlistener.onrgsextracheckedchanged(radiogroup, checkedid, i);
}
}
}
}
/**
* 切换tab
* @param idx
*/
private void showtab(int idx)
{
for(int i = 0; i < fragments.size(); i++)
{
fragment fragment = fragments.get(i);
fragmenttransaction ft = activity.getfragmentmanager().begintransaction();
if(idx == i)
{
ft.show(fragment);
}
else
{
ft.hide(fragment);
}
ft.commit();
}
currenttab = idx; // 更新目标tab为当前tab
}
public int getcurrenttab()
{
return currenttab;
}
public fragment getcurrentfragment()
{
return fragments.get(currenttab);
}
public onrgsextracheckedchangedlistener getonrgsextracheckedchangedlistener()
{
return onrgsextracheckedchangedlistener;
}
public void setonrgsextracheckedchangedlistener(onrgsextracheckedchangedlistener onrgsextracheckedchangedlistener)
{
this.onrgsextracheckedchangedlistener = onrgsextracheckedchangedlistener;
}
/**
* 切换tab额外功能功能接口
*/
public interface onrgsextracheckedchangedlistener
{
void onrgsextracheckedchanged(radiogroup radiogroup, int checkedid, int index);
}
}
2.activity_main.xml布局文件：
<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@android:color/white"
android:orientation="vertical" >
<linearlayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<framelayout
android:id="@+id/tab_content"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1.0"
android:background="#77557799" />
<radiogroup
android:id="@+id/tabs_rg"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="horizontal"
android:paddingbottom="7dp"
android:paddingtop="7dp" >
<radiobutton
android:id="@+id/tab_rb_a"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:background="@drawable/selector_tab"
android:button="@null"
android:checked="true"
android:drawabletop="@drawable/tablatestalert"
android:gravity="center"
android:singleline="true"
android:text="tab1"
android:textcolor="#000000"
android:textsize="13sp" />
<radiobutton
android:id="@+id/tab_rb_b"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:background="@drawable/selector_tab"
android:button="@null"
android:drawabletop="@drawable/tabsearch"
android:gravity="center"
android:singleline="true"
android:text="tab2"
android:textcolor="#000000"
android:textsize="13sp" />
<radiobutton
android:id="@+id/tab_rb_c"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:background="@drawable/selector_tab"
android:button="@null"
android:drawabletop="@drawable/tabrecommd"
android:gravity="center"
android:singleline="true"
android:text="tab3"
android:textcolor="#000000"
android:textsize="13sp" />
</radiogroup>
</linearlayout>
</linearlayout>
3.mainactivity类：
/**
*@description:
*@author:nate robinson
*@since:2015-2-12
*/
public class mainactivity extends activity
{
private radiogroup rgs;
private list<fragment> fragments = new arraylist<fragment>();
private int index;
private static boolean isexit = false;
private static boolean hastask = false;
private radiobutton button;
private timer texit = new timer();
private timertask task = new timertask()
{
@override
public void run()
{
isexit = false;
hastask = true;
}
};
private fragmenttabadapter tabadapter;
@override
public void oncreate(bundle savedinstancestate)
{
super.oncreate(savedinstancestate);
setcontentview(r.layout.activity_main);
fragments.add(new fragmentone());
fragments.add(new fragmenttwo());
fragments.add(new fragmentthree());
rgs = (radiogroup) findviewbyid(r.id.tabs_rg);
button = (radiobutton) findviewbyid(r.id.tab_rb_a);
tabadapter = new fragmenttabadapter(this, fragments, r.id.tab_content, rgs);
tabadapter.setonrgsextracheckedchangedlistener(new fragmenttabadapter.onrgsextracheckedchangedlistener()
{
@override
public void onrgsextracheckedchanged(radiogroup radiogroup, int checkedid, int index)
{
// 利用这个index可以实现，如果不是在主页，按第一遍让它先跳转到第一个fragment
system.out.println("extra---- " + index + " checked!!! ");
mainactivity.this.index = index;
}
});
}
@override
public boolean onkeydown(int keycode, keyevent event)
{
if(keycode == keyevent.keycode_back)
{
if(index == 0)
{
if(isexit == false)
{
isexit = true;
toast.maketext(mainactivity.this, "再按一次退出程序", toast.length_short).show();
if(!hastask)
{
texit.schedule(task, 1000);
}
}
else
{
finish();
system.exit(0);
}
}
else
{
// 如果不是在主页，按第一遍让它先跳转到第一个fragment
// 利用上面的check方法会导致oncheckedchanged方法被执行多次
// rgs.check(button.getid());
button.setchecked(true);
}
}
return false;
}
}
为了能同时学习fragment生命周期，我在fragment每个生命周期方法中加入了log打印，一个有三个这样的fragment，我只贴出其中一个代码，其余和这个一样：
/**
*@description:
*@author:nate robinson
*@since:2015-2-12
*/
public class fragmentone extends basefragment
{
private view view;
@override
public void onattach(activity activity)
{
super.onattach(activity);
log.d(tag, "1==>fragmentone=>onattach");
}
@override
public void oncreate(bundle savedinstancestate)
{
log.d(tag, "2==>fragmentone==>oncreate");
super.oncreate(savedinstancestate);
}
@override
public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate)
{
log.d(tag, "3==>fragmentone==>oncreateview");
view = inflater.inflate(r.layout.fragment1, container, false);
textview tv = (textview) view.findviewbyid(r.id.tv);
tv.settext("fragmentone");
return view;
}
@override
public void onactivitycreated(bundle savedinstancestate)
{
log.d(tag, "4==>fragmentone==>onactivitycreated");
super.onactivitycreated(savedinstancestate);
}
@override
public void onstart()
{
log.d(tag, "5==>fragmentone==>onstart");
super.onstart();
}
@override
public void onresume()
{
log.d(tag, "6==>fragmentone==>onresume");
super.onresume();
}
@override
public void onpause()
{
log.d(tag, "7==>fragmentone==>onpause");
super.onpause();
}
@override
public void onstop()
{
log.d(tag, "8==>fragmentone==>onstop");
super.onstop();
}
@override
public void ondestroyview()
{
log.d(tag, "9==>fragmentone==>ondestroyview");
super.ondestroyview();
}
@override
public void ondestroy()
{
log.d(tag, "10==>fragmentone==>ondestroy");
super.ondestroy();
}
@override
public void ondetach()
{
log.d(tag, "11==>fragmentone==>ondetach");
super.ondetach();
}
@override
public void onviewcreated(view view, bundle savedinstancestate)
{
log.d(tag, "fragmentone==>onviewcreated");
super.onviewcreated(view, savedinstancestate);
}
}
在编写过程中，我为了实现如果不是在主页，按第一遍让它先跳转到第一个fragment这个效果，一开始使用了rgs.check(button.getid());这个方法，结果发现，这样的话oncheckedchanged监听事件会执行两次，后来改为button.setchecked(true);这个方法之后，成功解决了这个问题。
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