Fragment在Activity中的应用指南

Fragment在Activity中的应用1创建一个空的Activity我们首先创建一个空的Activity，水平排列。如下所示res/layour/main.xml：<?xmlversion="1.0"encoding="utf-8"?><LinearLayoutxmlns:android="/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="horizontal"></LinearLayout>com/fragment/FragmentDemoActivity.java：packagecom.fragment;importandroid.app.Activity;importandroid.os.Bundle;publicclassFragmentDemoActivityextendsActivity{/**Calledwhentheactivityisfirstcreated.*/@OverridepublicvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);}}

2创建Fragment我们创建两个Fragment，一个是目录TitlesFragment，一个是详情DetailsFragment。TitlesFragment集成ListFragment，实现目录列表。com/fragment/TitlesFragment.java：packagecom.fragment;importandroid.app.Activity;importandroid.app.AlertDialog;importandroid.app.FragmentTransaction;importandroid.app.ListFragment;importandroid.os.Bundle;importandroid.view.LayoutInflater;importandroid.view.View;importandroid.view.ViewGroup;importandroid.widget.ArrayAdapter;importandroid.widget.ListView;publicclassTitlesFragmentextendsListFragment{staticString[]array;booleanmDualPane;intmCurCheckPosition=0;@OverridepublicvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);}@OverridepublicViewonCreateView(LayoutInflaterinflater,ViewGroupcontainer,BundlesavedInstanceState){returnsuper.onCreateView(inflater,container,savedInstanceState);}@OverridepublicvoidonPause(){super.onPause();}@OverridepublicvoidonStop(){super.onStop();}@OverridepublicvoidonAttach(Activityactivity){super.onAttach(activity);}@OverridepublicvoidonStart(){super.onStart();}@OverridepublicvoidonResume(){super.onResume();}@OverridepublicvoidonDestroy(){super.onDestroy();}@OverridepublicvoidonActivityCreated(BundlesavedInstanceState){super.onActivityCreated(savedInstanceState);array=getResources().getStringArray(R.array.countries_array);setListAdapter(newArrayAdapter<String>(getActivity(),android.R.layout.simple_list_item_1,array));ViewdetailsFrame=getActivity().findViewById(R.id.details);mDualPane=detailsFrame!=null&&detailsFrame.getVisibility()==View.VISIBLE;if(savedInstanceState!=null){mCurCheckPosition=savedInstanceState.getInt("curChoice",0);//从保存的状态中取出数据}if(mDualPane){getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);showDetails(mCurCheckPosition);}}@OverridepublicvoidonSaveInstanceState(BundleoutState){super.onSaveInstanceState(outState);outState.putInt("curChoice",mCurCheckPosition);}@OverridepublicvoidonListItemClick(ListViewl,Viewv,intposition,longid){super.onListItemClick(l,v,position,id);showDetails(mCurCheckPosition);}voidshowDetails(intindex){mCurCheckPosition=index;if(mDualPane){getListView().setItemChecked(index,true);DetailsFragmentdetails=(DetailsFragment)getFragmentManager().findFragmentById(R.id.details);if(details==null||details.getShownIndex()!=index){details=DetailsFragment.newInstance(mCurCheckPosition);//得到一个fragment事务（类似sqlite的操作）FragmentTransactionft=getFragmentManager().beginTransaction();ft.replace(R.id.details,details);ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);mit();//提交}}else{newAlertDialog.Builder(getActivity()).setTitle(android.R.string.dialog_alert_title).setMessage(array[index]).setPositiveButton(android.R.string.ok,null).show();}}}DetailsFragment显示点击某个目录的详情，com/fragment/DetailsFragment.java：packagecom.fragment;importandroid.app.Fragment;importandroid.os.Bundle;importandroid.util.TypedValue;importandroid.view.LayoutInflater;importandroid.view.View;importandroid.view.ViewGroup;importandroid.widget.ScrollView;importandroid.widget.TextView;publicclassDetailsFragmentextendsFragment{staticString[]array;@OverridepublicvoidonCreate(BundlesavedInstanceState){//TODOAuto-generatedmethodstubsuper.onCreate(savedInstanceState);setHasOptionsMenu(true);}publicstaticDetailsFragmentnewInstance(intindex){DetailsFragmentdetails=newDetailsFragment();Bundleargs=newBundle();args.putInt("index",index);details.setArguments(args);returndetails;}publicintgetShownIndex(){returngetArguments().getInt("index",0);}@OverridepublicViewonCreateView(LayoutInflaterinflater,ViewGroupcontainer,BundlesavedInstanceState){//TODOAuto-generatedmethodstubif(container==null)returnnull;array=getResources().getStringArray(R.array.countries_array);ScrollViewscroller=newScrollView(getActivity());/*GridViewgridview=(GridView)getActivity().findViewById(R.id.gridview);gridview.setAdapter(newImageAdapter(getActivity()));gridview.setOnItemClickListener(newOnItemClickListener(){publicvoidonItemClick(AdapterView<?>parent,Viewv,intposition,longid){Toast.makeText(DetailsFragment.this.getActivity(),""+position,Toast.LENGTH_SHORT).show();}});*//*//定义UI组件finalImageViewiv=(ImageView)getActivity().findViewById(R.id.ImageView01);Galleryg=(Gallery)getActivity().findViewById(R.id.Gallery01);//设置图片匹配器g.setAdapter(newImageAdapter(getActivity()));//设置AdapterView点击监听器，Gallery是AdapterView的子类g.setOnItemClickListener(newOnItemClickListener(){@OverridepublicvoidonItemClick(AdapterView<?>parent,Viewview,intposition,longid){//显示点击的是第几张图片Toast.makeText(DetailsFragment.this.getActivity(),""+position,Toast.LENGTH_LONG).show();//设置背景部分的ImageView显示当前Item的图片iv.setImageResource(((ImageView)view).getId());}});*/TextViewtext=newTextView(getActivity());intpadding=(int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,4,getActivity().getResources().getDisplayMetrics());text.setPadding(padding,padding,padding,padding);scroller.addView(text);text.setText(array[getShownIndex()]);/*ButtonbtnContact=(Button)getActivity().findViewById(R.id.bt1);btnContact.setOnClickListener(newView.OnClickListener(){@OverridepublicvoidonClick(Viewv){//TODOAuto-generatedmethodstubIntentintent=newIntent(getActivity(),MainHelloGallery.class);startActivity(intent);}});*/returnscroller;}/*@OverridepublicvoidonCreateOptionsMenu(Menumenu,MenuInflaterinflater){//TODOAuto-generatedmethodstubsuper.onCreateOptionsMenu(menu,inflater);menu.add("Menu1a").setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);menu.add("Menu1b").setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);}@OverridepublicbooleanonOptionsItemSelected(MenuItemitem){//TODOAuto-generatedmethodstubToast.makeText(getActivity(),"indexis"+getShownIndex()+"&&menutextis"+item.getTitle(),1000).show();returnsuper.onOptionsItemSelected(item);}*/}

3将Fragment添加至Activity中此时，已经实现了Activity和两个Fragment，将Fragment添加至Activity有两种方式。3.1在activity的layout文件中声明fragment<?xmlversion="1.0"encoding="utf-8"?><LinearLayoutxmlns:android="/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="horizontal"><fragmentandroid:id="@+id/titles"android:layout_width="0px"