android 应用架构随笔五（ActionBar与侧滑菜单DrawerLayout）

ActionBar（V7）的添加非常简单，只需要在AndroidManifest.xml中指定Application或Activity的theme是Theme.Holo或其子类就可以了，在Android 3.0及更高的版本中，Activity中都默认包含有ActionBar组件。

drawerLayout（V4）是Support Library包中实现了侧滑菜单效果的控件，可以说drawerLayout是因为第三方控件如MenuDrawer等的出现之后，google借鉴而出现的产物。drawerLayout分为侧边菜单和主内容区两部分，侧边菜单可以根据手势展开与隐藏（drawerLayout自身特性），主内容区的内容可以随着菜单的点击而变化（这需要使用者自己实现）。

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
                                        android:id="@+id/drawer_layout"
                                        xmlns:tools="http://schemas.android.com/tools"
                                        android:layout_width="match_parent"
                                        android:layout_height="match_parent">

    <RelativeLayout
            android:id="@+id/content_frame"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        <com.heima.googleplay.widget.PagerTab
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="42dip"
                android:background="@drawable/bg_tab"/>

        <android.support.v4.view.ViewPager
                android:id="@+id/pager"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_below="@+id/tabs"
                tools:context=".MainActivity"/>
    </RelativeLayout>

    <FrameLayout
            android:id="@+id/start_drawer"
            android:layout_width="250dp"
            android:layout_height="match_parent"
            android:layout_gravity="start"
            android:background="@drawable/bg_tab"></FrameLayout>
</android.support.v4.widget.DrawerLayout>

分主页和侧滑页两个页面，侧滑页为：

<FrameLayout
android:id="@+id/start_drawer"
android:layout_width="250dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="@drawable/bg_tab"></FrameLayout>

start从左到右滑动，end从右到左滑动

继承ActionBarActivity 

import android.app.Application;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;

public abstract class BaseActivity extends ActionBarActivity {

    private static BaseActivity mForegroundActivity;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        initView();
    }
    
    protected abstract void initView() ;

    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();
        this.mForegroundActivity = this;
    }
    
    
    public static BaseActivity getForegroundActivity(){
        return mForegroundActivity;
    }
}

setContentView(R.layout.activity_main);

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.Menu;

import com.heima.googleplay.fragment.AppFragment;
import com.heima.googleplay.fragment.BaseFragment;
import com.heima.googleplay.fragment.FragmentFactory;
import com.heima.googleplay.fragment.GameFragment;
import com.heima.googleplay.fragment.HomeFragment;
import com.heima.googleplay.utils.UIUtils;
import com.heima.googleplay.widget.PagerTab;

public class MainActivity extends BaseActivity implements OnPageChangeListener {


    private PagerTab mTabs;
    private ViewPager mPager;


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

     private class MainAdapter extends FragmentStatePagerAdapter{

        private String[] tab_names;
        private BaseFragment fragment;

        public MainAdapter(FragmentManager fm) {
            super(fm);
            tab_names = UIUtils.getStringArray(R.array.tab_names);
        }

        @Override
        public CharSequence getPageTitle(int position) {
            // TODO Auto-generated method stub
            return tab_names[position];
        }
        
        @Override
        public Fragment getItem(int position) {
            
            return FragmentFactory.createFragment(position);
        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return tab_names.length;
        }
         
     }

    @Override
    protected void initView() {
        setContentView(R.layout.activity_main);
        mTabs = (PagerTab) findViewById(R.id.tabs);
        mPager = (ViewPager) findViewById(R.id.pager);
        MainAdapter adapter = new MainAdapter(getSupportFragmentManager());
        mPager.setAdapter(adapter);
        //绑定到一起
        mTabs.setViewPager(mPager);
        mTabs.setOnPageChangeListener(this);
    }

    @Override
    public void onPageScrollStateChanged(int arg0) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void onPageScrolled(int arg0, float arg1, int arg2) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void onPageSelected(int arg0) {
        BaseFragment fragment = FragmentFactory.createFragment(arg0);
        fragment.show();
    }

}