15 ActionBar.Tab 以及保存fragment对象 代码案例

2023-07-20 12:30:22

  • 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;
    
    }

}
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