[android] 新聞客戶端實現左側導航點擊切換

設置主佈局文件，為根佈局設置一個id，作為內容區

給ListView的條目設置點擊事件，setOnItemClickListener()方法，參數：上下文

當前的Fragment實現OnItemClickListener介面

實現onItemClick()方法

switch判斷一下當前菜單的索引位置，根據索引來實例化不同的Fragment對象

調用getActivity()方法，得到宿主Activity對象，這個activity暴露一個方法，替換fragment

使用關鍵字instances of判斷getActivity()得到的是MainActivity類的實例

調用宿主Activity對象的switchMenuFragment()方法，切換內容部分的fragment，參數：Fragment對象

宿主activity暴露方法switchMenuFragment()，切換內容區fragment，參數：Fragment對象

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

調用SlidingMenu對象的toggle()方法，關閉左側菜單

設置預設，當app第一次打開時顯示導航第一個的內容

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);
        //設置滑動菜單
        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();
        //替換導航fragemnt
        MenuFragment menuFragment=new MenuFragment();
        ft.replace(R.id.ll_left_menu, menuFragment);
        //替換內容fragment
        IndexFragment index=new IndexFragment();
        ft.replace(R.id.ll_main_content, index).commit();
        
    }
    /**
     * 暴露方法切換內容區
     * @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;
    //載入佈局文件
    @Override
    public View onCreateView(LayoutInflater inflater,
            @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.list_view, null);
        return view;
    }
    //設置listview數據
    @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("新聞");
        data.add("發現");
        data.add("關註");
        ListAdapter adapter = new ArrayAdapter<>(getActivity(),
                android.R.layout.simple_list_item_1, android.R.id.text1,
                data);
        listview.setAdapter(adapter);
        listview.setOnItemClickListener(this);
        
    }
    /**
     * 導航點擊
     */
    @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);
            }
        }
    }
}