Android之Fragment案例解析

创建工程fragmentdamel


第一步创建Data.java

package com.example.fragmentdamel;


public final class Data {
	//标题
	public static final String[] TITLES={
		"线性布局",
		"表格布局",
		"帧布局",
		"相对布局",
	};
	//详细内容
	public static final String[] DETAIL = {
		"线性布局",
		"表格布局",
		"帧布局",
		"相对布局"
	};
}

第二步：
创建DetailFragment

package com.example.fragmentdamel;


import android.app.Fragment;
import android.os.Bundle;


import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ScrollView;
import android.widget.TextView;


public class DetailFragment extends Fragment {
	public static DetailFragment newInstance(int index){
		DetailFragment f = new DetailFragment();


		Bundle bundle = new Bundle();
		bundle.putInt("index", index);//将索引值添加到Bundle对象中
		f.setArguments(bundle);//将bundle对象作为Fragment的参数保存
		return f;
	}


	public int getShownIndex(){
		return getArguments().getInt("index",0);//获取要显示的列表项的索引
	}
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		//return super.onCreateView(inflater, container, savedInstanceState);
		if(container == null){
			return null;
		}
		ScrollView scroller = new ScrollView(getActivity());//创建一个滚动视图


		TextView text = new TextView(getActivity());//创建一个文本框对象
		text.setPadding(10, 10, 10, 10);//设置内边框
		scroller.addView(text);//将文本框添加到滚动视图中
		text.setText(Data.DETAIL[getShownIndex()]);//设置文本框要显示的内容
		return scroller;
	}
}

第三步
创建ListFragment

package com.example.fragmentdamel;


import android.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;






import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;


public class ListFragment extends android.app.ListFragment{
	boolean dualPane;
	int curCheckPosition = 0;
	@Override
	public void onActivityCreated(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onActivityCreated(savedInstanceState);
		//为列表设置适配器
		setListAdapter(new ArrayAdapter<String>(getActivity(), 


android.R.layout.simple_list_item_checked,Data.TITLES));
		//获取布局文件添加的FragmentLayout帧布局管理器
		View detailFrame = getActivity().findViewById(R.id.detail);
		//判断是否在一屏上同时显示列表和详细内容
		dualPane = detailFrame != null && detailFrame.getVisibility() 


==View.VISIBLE;
		//更新当前选择的索引位置
		if(savedInstanceState != null){
			curCheckPosition = savedInstanceState.getInt("curChoice",0);


		}
		//如果在一屏上同时显示列表和详细内容
		if(dualPane){
			//设置列表为单选模式
			getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
			showDetails(curCheckPosition);//显示详细内容
		}
	}
	//重写方法
	@Override
	public void onSaveInstanceState(Bundle outState) {
		// TODO Auto-generated method stub
		super.onSaveInstanceState(outState);
		outState.putInt("curChoice", curCheckPosition);
	}


	@Override
	public void onListItemClick(ListView l, View v, int position, long id) {
		// TODO Auto-generated method stub
		showDetails(position);//显示详细内容
	}


	void showDetails(int index){
		curCheckPosition = index;//更新保存当前索引位置的变量的值为当前选中值
		if(dualPane){//当在一屏上同时显示列表和详细内容时
			getListView().setItemChecked(index, true);//设置选中列表为选中


状态
			DetailFragment details = (DetailFragment) getFragmentManager


().findFragmentById(R.id.detail);//获取用于显示详细内容的Fragment
			if(details == null || details.getShownIndex()!=index){
				//创建一个新的DetailFragment实例用于显示当前选择项对应


的详细内容
				details = DetailFragment.newInstance(index);
				//要在activity中管理fragment 需要使用FragmentManager
				FragmentTransaction ft = getFragmentManager


().beginTransaction();//获得一个FragmentTransaction的实例
				ft.replace(R.id.detail, details);//替换原来显示的详细


内容
				ft.addToBackStack(null);
				ft.setTransition


(FragmentTransaction.TRANSIT_FRAGMENT_FADE);//设置转换效果
				ft.commit();//提交事务


			}
			else {//在一屏上只能显示列表或一个详细内容时
				Intent intent = new Intent(getActivity(), 


MainActivity.DetailActivity.class);
				intent.putExtra("index", index);
				startActivity(intent);
			}


		}
	}
}

第五步创建MainActivity

package com.example.fragmentdamel;


import android.os.Bundle;
import android.app.Activity;
import android.content.res.Configuration;
import android.view.Menu;


public class MainActivity extends Activity {


	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}
	//创建一个继承Activity的内部类，用于在手机界面中通过Activity显示详细内容
	public static  class DetailActivity extends Activity{
		@Override
		protected void onCreate(Bundle savedInstanceState) {
			// TODO Auto-generated method stub
			super.onCreate(savedInstanceState);
			//判断是否为横屏如果为横屏，结束当前的Activity，准备使用


Fragment显示详细内容


			if(getResources().getConfiguration().orientation == 


Configuration.ORIENTATION_LANDSCAPE){
				finish();
				return ;
			}
			if(savedInstanceState == null){
				//在初始化时插入一个显示详细内容的Fragment
				DetailFragment details = new DetailFragment();
				details.setArguments(getIntent().getExtras());//设置要


传递的参数
				getFragmentManager().beginTransaction().add


(android.R.id.content, details).commit();//添加一个显示详细内容的Fragment
			}
		}
	}






}

创建main_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >


    <fragment
        android:id="@+id/titles"
        android:layout_width="0px"
        android:layout_height="match_parent"
        android:layout_weight="1"
        class="com.example.fragmentdamel.ListFragment" />


    <FrameLayout
        android:id="@+id/detail"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="2"
        android:background="?android:attr/detailsElementBackground" >
    </FrameLayout>


</LinearLayout>