Android-实现切换Fragment页功能
場景:使用Fragment實現切頁。
類結構:
一:Activity
Activity中使用getSupportFragmentManager().beginTransaction()來填充一個Fragment(管理用的FragmentA)
Activity部分代碼:
FragmentA fragment = FragmentA.newInstant(null); getSupportFragmentManager().beginTransaction().add(R.id.f_tab_fragment,fragment).commit();XML:
<FrameLayoutandroid:id="@+id/fl_container"android:layout_width="match_parent"android:layout_above="@+id/f_tab_fragment"android:layout_height="match_parent"/><FrameLayoutandroid:id="@+id/f_tab_fragment"android:layout_width="match_parent"android:layout_height="52dp"android:layout_alignParentBottom="true"/>?
二:FragmentA
加載一個主FragmentA,作為管理其它子葉片FragmentX。
現在比如有兩個子葉片FragmentB、FragmentC.
FragmentA 使用FragmentManager和FragmentTransaction管理FragmentB、FragmentC的切換?
FragmentA代碼:
public class FragmentA extends BaseFragment {private static final String TAB_HOME = com.timediffproject.module.home.MyMainFragment.class.getName();private static final String TAB_TEST = com.timediffproject.module.home.TestFragment.class.getName();private BaseFragment mLastShowFragment;private static TabFragment fragment;public static TabFragment newInstant(Bundle bundle){if (fragment == null){fragment = new TabFragment();fragment.setArguments(bundle);}return fragment;}@Overridepublic void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);initTabInfo();}private void initTabInfo(){FragmentManager fm = getFragmentManager();if (fm == null){return;}FragmentTransaction ft = fm.beginTransaction();BaseFragment home = (BaseFragment) fm.findFragmentByTag(TAB_HOME);if (home != null){ft.hide(home);}BaseFragment test = (BaseFragment) fm.findFragmentByTag(TAB_TEST);if (test != null){ft.hide(test);}ft.commit();}@Nullable@Overridepublic View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {return inflater.inflate(R.layout.fragment_tab,container,false);}@Overridepublic void onViewCreated(View view, @Nullable Bundle savedInstanceState) {super.onViewCreated(view, savedInstanceState);view.findViewById(R.id.btn_change_home).setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {switchTo(TAB_HOME,null);}});view.findViewById(R.id.btn_change_test).setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {switchTo(TAB_TEST,null);}});switchTo(TAB_HOME,null);}//切換Fragment的方式(FragmentB、FragmentC)//tab為Fragment的類名(如:FragmentB.class.getName())//R.id.fl_container是在Activity的布局里,不是在FragmentA的布局里private void switchTo(String tab, Bundle bundle){//初始化管理Fragment的類FragmentManager fm = getFragmentManager();if (fm == null){return;}FragmentTransaction ft = fm.beginTransaction();//從FragmentManager里尋找類名為tab的FragmentBaseFragment fragment = (BaseFragment)fm.findFragmentByTag(tab);if (fragment == null){fragment = (BaseFragment) Fragment.instantiate(getActivity(),tab);fragment.setArguments(bundle);ft.add(R.id.fl_container,fragment,tab);}else{ft.show(fragment);}//隱藏現在正顯示的Fragmentif (mLastShowFragment != null) {ft.hide(mLastShowFragment);}//記錄最后點擊的FragmentmLastShowFragment = fragment;ft.commitAllowingStateLoss();}}?
XML:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="horizontal" android:layout_width="match_parent"android:layout_height="52dp"><Buttonandroid:id="@+id/btn_change_home"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="切換home"/><Buttonandroid:id="@+id/btn_change_test"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="切換test"/></LinearLayout>?
?三:FragmentX(FragmentB、FragmentC)
子頁的邏輯根據具體業務自己定義,實現與一般Fragmeng一樣
例如:
public class TestFragment extends BaseFragment {@Nullable@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {return inflater.inflate(R.layout.fragment_test,container,false);}@Overridepublic void onViewCreated(View view, Bundle savedInstanceState) {super.onViewCreated(view, savedInstanceState);}}?
到這里,就可以簡單的實現-用底部Tab切換Fragment實現切頁的功能
?附圖:
? ?
?
PS:實現過程中出現的錯誤?
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
正確方式: 有關的fragment的初始化布局應該加上false,與父類布局建立關系。
原因:不加的話這個inflater出來的view系統會綁定一個未知父類,這時候當你把這個fragment又作為子頁綁定給Activity或者另一個fragment時,就會出現以上錯誤。
@Nullable@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {//這里正確的寫法是://return inflater.inflate(R.layout.fragment_test,container,false);return inflater.inflate(R.layout.fragment_test,container);}?
轉載于:https://www.cnblogs.com/Sweet-Candy/p/6411105.html
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