FrameLayout和Fragment处理Android应用UI布局实例
将Fragment与Layout结合使用,一般都是主Activity以frame填充Activity的方式交互管理Fragment :
1.由于用到getSupportFragmentManager()之类,所以主Activity的extends需为FragmentActivity:
public class MainActivity extends FragmentActivity{ .......... }
2.主Activity的layout(xml文件)中建立多个Frame并定义其Android:id="@+id/XXX"
3.主Activity内操作函数中,由查找id来对这些FrameLayout进行Activity填充:
添加语句如下
getSupportFragmentManager().beginTransaction().add(R.id.fragment_container2,new NullFrag()).commit();
取得支持Fragment管理()->开始交易()->添加(frame的id , Fragment).交付();
替换语句如下
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container2,new NullFrag()).commit();
取得支持Fragment管理()->开始交易()->替代(frame的id , Fragment).交付();
例:
public void click_btn_flag02(View view){
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container2,new MidFrag()).commit();
}
注:函数参数要用View
下面我们来看实例:
效果图的左边是一个列表,右边是列表item的详情。
先看一下布局文件(layout):
<?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="match_parent"> <fragment class="com.fragment.main.TitlesFragment" android:id="@+id/titles" android:layout_weight="1" android:layout_width="0px" android:layout_height="match_parent" /> <FrameLayout android:id="@+id/details" android:layout_weight="1" android:layout_width="0px" android:layout_height="match_parent" android:background="?android:attr/detailsElementBackground" /> </LinearLayout>
布局文件中使用了fragment标签和FrameLayout标签。Android Fragment使用 中介绍了2中嵌入Fragment的方法,这个实例中都用到,从布局文件看到有了fragment标签,这是一种使用方法,FrameLayout标签将会成为第二种加载fragment的载体view。
看一下程序实现(com.fragment.main.TitlesFragment):
public class TitlesFragment extends ListFragment { int mCurCheckPosition = 0; int mShownCheckPosition = -1; @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); setListAdapter(new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_activated_1, Shakespeare.TITLES)); //使用静态数组填充列表 if (savedInstanceState != null) { mCurCheckPosition = savedInstanceState.getInt("curChoice", 0); mShownCheckPosition = savedInstanceState.getInt("shownChoice", -1); } getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE); showDetails(mCurCheckPosition); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt("curChoice", mCurCheckPosition); outState.putInt("shownChoice", mShownCheckPosition); } @Override public void onListItemClick(ListView l, View v, int position, long id) { showDetails(position); } /** *显示listview item 详情 */ void showDetails(int index) { mCurCheckPosition = index; getListView().setItemChecked(index, true); if (mShownCheckPosition != mCurCheckPosition) { DetailsFragment df = DetailsFragment.newInstance(index); FragmentTransaction ft = getFragmentManager() .beginTransaction(); ft.replace(R.id.details, df); ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE); ft.commit(); mShownCheckPosition = index; } } }
TitlesFragment
TitlesFragment继承自Fragment的子类ListFragment,使用了一个静态数组填充列表,重写了onListItemClick方法,showDetails方法展示ListView item的详情。
DetailsFragment df = DetailsFragment.newInstance(index);//获取详情Fragment的实例 FragmentTransaction ft = getFragmentManager().beginTransaction();//获取FragmentTransaction 实例 ft.replace(R.id.details, df); //使用DetailsFragment 的实例 ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE); ft.commit();//提交
看一下DetailsFragment :
public class DetailsFragment extends Fragment { /** * Create a new instance of DetailsFragment, initialized to * show the text at 'index'. */ public static DetailsFragment newInstance(int index) { DetailsFragment f = new DetailsFragment(); // Supply index input as an argument. Bundle args = new Bundle(); args.putInt("index", index); f.setArguments(args); return f; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { if (container == null) { return null; } ScrollView scroller = new ScrollView(getActivity()); TextView text = new TextView(getActivity()); int padding = (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_DIP, 4, getActivity().getResources() .getDisplayMetrics()); text.setPadding(padding, padding, padding, padding); scroller.addView(text); text.setText(Shakespeare.DIALOGUE[getArguments().getInt("index", 0)]); return scroller; } }
DetailsFragment 中使用newInstance(int index)方法产生DetailsFragment 实例并接受整型参数,重载了onCreateView方法创建view。