15 ActionBar.Tab 以及保存fragment对象 代码案例

API 21弃用

values 中 string文件源码:

<?xml version="1.0" encoding="utf-8"?>
<resources>

<string name="app_name">Day15_Actionbar_demo4</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<!--
nums 对应网址
-->
<string-array name="paths">
<item>http://c.m.163.com/nc/article/headline/T1348647853363/0-20.html</item>
<item>http://c.m.163.com/nc/article/list/T1348648517839/0-20.html</item>
<item>http://c.m.163.com/nc/article/list/T1348649079062/0-20.html</item>
<item>http://c.m.163.com/nc/article/list/T1348648756099/0-20.html</item>
</string-array>
<!--由于地址返回json的根目录中只有这个名字 所以写死每个地址的根目录名 就可以只用一个解析了  -->
<string-array name="nums">
<item>T1348647853363</item>
<item>T1348648517839</item>
<item>T1348649079062</item>
<item>T1348648756099</item>
</string-array>

</resources>

activity_main.xml源码:

<!-- 直接作为fragment的容器 -->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/rl_fragment_id"
tools:context=".MainActivity" >

</RelativeLayout>

fragment填充对象源码:

<?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="vertical" >

<ListView
android:id="@+id/lv"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>

</LinearLayout>

MainActivity.java:

package com.qf.day15_actionbar_demo4;

import java.util.HashMap;
import java.util.Map;

import com.qf.day15_actionbar_demo4.fragment.MyFragment;

import android.os.Bundle;
import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.ActionBar.TabListener;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.util.Log;
import android.view.Menu;
import android.widget.Toast;

public class MainActivity extends Activity implements TabListener{

private Map<Integer, Fragment> fragmentMap;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//将集合实例化
fragmentMap = new HashMap<Integer, Fragment>();

//获取ActionBar
ActionBar actionBar = getActionBar();
//设置导航模式
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

ActionBar.Tab tab = actionBar.newTab();
tab.setIcon(android.R.drawable.ic_menu_add);
tab.setText("头条");
tab.setTabListener(this);
actionBar.addTab(tab, true);

tab = actionBar.newTab();
tab.setIcon(android.R.drawable.ic_menu_call);
tab.setText("娱乐");
tab.setTabListener(this);
actionBar.addTab(tab);

tab = actionBar.newTab();
tab.setIcon(android.R.drawable.ic_menu_camera);
tab.setText("财经");
tab.setTabListener(this);
actionBar.addTab(tab);

tab = actionBar.newTab();
tab.setIcon(android.R.drawable.ic_menu_crop);
tab.setText("体育");
tab.setTabListener(this);
actionBar.addTab(tab);
}

/**
* 选择Tab 事件监听
*/
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
//你点击的是那个Tab 位置获取出来
//      int pos = tab.getPosition();
//
//      MyFragment myFragment = new MyFragment();
//
//      Bundle bundle = new Bundle();
//      bundle.putInt("pos", pos);
//      myFragment.setArguments(bundle);
//
//
//      ft.replace(R.id.rl_fragment_id, myFragment);
//      //.commit();  不需要加提交  不需要 添加回退

Log.e("AAA", tab.getPosition()+"");

Fragment fragment = fragmentMap.get(tab.getPosition());

if(fragment==null){
fragment = new MyFragment();
Bundle bundle = new Bundle();
bundle.putInt("pos", tab.getPosition());
fragment.setArguments(bundle);
fragmentMap.put(tab.getPosition(), fragment);
ft.add(R.id.rl_fragment_id, fragment);

}else{
ft.show(fragment);
}
}

/**
* 重选Tab  双击
*/
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub

}

/**
* 用户选择另一个tab标签的时候触发
*/
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
//没有被选择的Tab
Fragment fragment = fragmentMap.get(tab.getPosition());
Toast.makeText(this, tab.getPosition()+"", 0).show();
if(fragment!=null){
ft.hide(fragment);
}
}

}

MyTask.java 一个异步任务 用于加载网络数据:

package com.qf.day15_actionbar_demo4.asynctask;

import java.util.List;

import com.qf.day15_actionbar_demo4.interface0.CallBackData;
import com.qf.day15_actionbar_demo4.utils.HttpUtils;
import com.qf.day15_actionbar_demo4.utils.ParseJson;

import android.os.AsyncTask;

public class MyTask extends AsyncTask<String, Void, List<String>>{

private String num;
private CallBackData callBackData;

public MyTask(String num,CallBackData callBackData){
this.num = num;
this.callBackData = callBackData;
}

@Override
protected List<String> doInBackground(String... params) {
// TODO Auto-generated method stub
String jsonStr = HttpUtils.getStr(params[0]);
//解析数据
return ParseJson.getData(num, jsonStr);
}

@Override
protected void onPostExecute(List<String> result) {
// TODO Auto-generated method stub
super.onPostExecute(result);

if(result!=null&&result.size()>0){
callBackData.sendData(result);
}

}

}

Fragment.java :

package com.qf.day15_actionbar_demo4.fragment;

import java.util.List;

import com.qf.day15_actionbar_demo4.R;
import com.qf.day15_actionbar_demo4.asynctask.MyTask;
import com.qf.day15_actionbar_demo4.interface0.CallBackData;

import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class MyFragment extends Fragment{

private ListView lv;

int pos ;

private String path,num;//请求地址 和请求数据的解析需要的对象

@Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);

pos = getArguments().getInt("pos");
String[] paths = getResources().getStringArray(R.array.paths);
String[] nums = getResources().getStringArray(R.array.nums);

path = paths[pos];
num = nums[pos];
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub

View view = inflater.inflate(R.layout.layout, container, false);

lv = (ListView) view.findViewById(R.id.lv);

return view;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onActivityCreated(savedInstanceState);
//开启异步任务  请求数据  展示数据

new MyTask(num, new CallBackData() {

@Override
public void sendData(List<String> list) {
// TODO Auto-generated method stub
Log.e("AAA", "===path=="+path);
Log.e("AAA", "===list=="+list.size());
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, list);

lv.setAdapter(adapter);
}
}).execute(path);

}

@Override
public void onHiddenChanged(boolean hidden) {

super.onHiddenChanged(hidden);
Log.e("AAA", "==onHiddenChanged==");
}

}

一个回调接口:

package com.qf.day15_actionbar_demo4.interface0;

import java.util.List;

public interface CallBackData {

public void sendData(List<String> list);

}

一个网络下载代码:

package com.qf.day15_actionbar_demo4.utils;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class HttpUtils {

public static String getStr(String path) {
// TODO Auto-generated method stub
HttpURLConnection connection = null;
InputStream is  = null;
try {
URL url = new URL(path);

connection= (HttpURLConnection) url.openConnection();

connection.setRequestMethod("GET");

connection.setConnectTimeout(5000);

connection.connect();

if(connection.getResponseCode()==200)
{
is = connection.getInputStream();

StringBuilder sBuilder = new StringBuilder();

byte[] buffer = new byte[1024];
int len = 0;

while ((len=is.read(buffer))!=-1) {

sBuilder.append(new String(buffer,0,len));

}

return sBuilder.toString();
}

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally
{
if(connection!=null)
{
connection.disconnect();
}
if (is!=null) {

try {
is.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return null;
}

}

解析json数据工具类:

package com.qf.day15_actionbar_demo4.utils;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class HttpUtils {

public static String getStr(String path) {
// TODO Auto-generated method stub
HttpURLConnection connection = null;
InputStream is  = null;
try {
URL url = new URL(path);

connection= (HttpURLConnection) url.openConnection();

connection.setRequestMethod("GET");

connection.setConnectTimeout(5000);

connection.connect();

if(connection.getResponseCode()==200)
{
is = connection.getInputStream();

StringBuilder sBuilder = new StringBuilder();

byte[] buffer = new byte[1024];
int len = 0;

while ((len=is.read(buffer))!=-1) {

sBuilder.append(new String(buffer,0,len));

}

return sBuilder.toString();
}

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally
{
if(connection!=null)
{
connection.disconnect();
}
if (is!=null) {

try {
is.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return null;
}

}