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：
/** *@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：
<"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。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持查字典教程网。
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