[android] 新闻客户端实现左侧导航点击切换

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设置主布局文件，为根布局设置一个id，作为内容区

给ListView的条目设置点击事件，setOnItemClickListener()方法，参数：上下文

当前的Fragment实现OnItemClickListener接口

实现onItemClick()方法

switch判断一下当前菜单的索引位置，根据索引来实例化不同的Fragment对象

调用getActivity()方法，得到宿主Activity对象，这个activity暴露一个方法，替换fragment

使用关键字instances of判断getActivity()得到的是MainActivity类的实例

调用宿主Activity对象的switchMenuFragment()方法，切换内容部分的fragment，参数：Fragment对象

宿主activity暴露方法switchMenuFragment()，切换内容区fragment，参数：Fragment对象

getSupportFragmentManager().beginTransaction().replace(R.id.ll_main_content, fragment).commit();

调用SlidingMenu对象的toggle()方法，关闭左侧菜单

设置默认，当app第一次打开时显示导航第一个的内容

MainActivity

package com.qingguow.news;

import android.os.Bundle;

import android.support.v4.app.Fragment;

import android.support.v4.app.FragmentTransaction;

import android.view.Window;

import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu;

import com.jeremyfeinstein.slidingmenu.lib.app.SlidingFragmentActivity;

import com.qingguow.news.fragment.IndexFragment;

import com.qingguow.news.fragment.MenuFragment;

public class MainActivity extends SlidingFragmentActivity {

    private SlidingMenu sm;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);

        //设置滑动菜单

        setBehindContentView(R.layout.menu);

        setContentView(R.layout.activity_main);

        sm=getSlidingMenu();

        sm.setMode(SlidingMenu.LEFT);

        sm.setBehindWidth(200);

        sm.setShadowDrawable(R.drawable.shape);

        sm.setShadowWidth(5);

        sm.setTouchModeAbove(SlidingMenu.TOUCHMODE_FULLSCREEN);

        FragmentTransaction ft=getSupportFragmentManager().beginTransaction();

        //替换导航fragemnt

        MenuFragment menuFragment=new MenuFragment();

        ft.replace(R.id.ll_left_menu, menuFragment);

        //替换内容fragment

        IndexFragment index=new IndexFragment();

        ft.replace(R.id.ll_main_content, index).commit();

    }

    /**

     * 暴露方法切换内容区

     * @param fragment

     */

    public void switchMenuFragment(Fragment fragment){

        getSupportFragmentManager().beginTransaction().replace(R.id.ll_main_content, fragment).commit();

        sm.toggle();

    }

}

MenuFragment.java

package com.qingguow.news.fragment;

import java.util.ArrayList;

import java.util.List;

import android.app.Activity;

import android.os.Bundle;

import android.support.annotation.Nullable;

import android.support.v4.app.Fragment;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.ArrayAdapter;

import android.widget.ListAdapter;

import android.widget.ListView;

import com.qingguow.news.MainActivity;

import com.qingguow.news.R;

public class MenuFragment extends Fragment implements OnItemClickListener {

    private View view;

    //加载布局文件

    @Override

    public View onCreateView(LayoutInflater inflater,

            @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        view = inflater.inflate(R.layout.list_view, null);

        return view;

    }

    //设置listview数据

    @Override

    public void onActivityCreated(@Nullable Bundle savedInstanceState) {

        super.onActivityCreated(savedInstanceState);

        ListView listview = (ListView) view.findViewById(R.id.lv_menu);

        List<String> data=new ArrayList<String>();

        data.add("新闻");

        data.add("发现");

        data.add("关注");

        ListAdapter adapter = new ArrayAdapter<>(getActivity(),

                android.R.layout.simple_list_item_1, android.R.id.text1,

                data);

        listview.setAdapter(adapter);

        listview.setOnItemClickListener(this);

    }

    /**

     * 导航点击

     */

    @Override

    public void onItemClick(AdapterView<?> parent, View view, int position,

            long id) {

        Fragment fragment=null;

        switch (position) {

        case 0:

            fragment=new IndexFragment();

            break;

        default:

            break;

        }

        if(fragment!=null){

            Activity activity=getActivity();

            if(activity instanceof MainActivity){

                ((MainActivity) activity).switchMenuFragment(fragment);

            }

        }

    }

}