2.抽取代码(BaseActivity)

知识点

• 俩种退出程序的方法
• 复制集合
• 同步的用法
• 字符数组
• 工厂模式，生产fatgment，解决了碎片重复创建的问题
• 全局上下文
• actionbar用法
• fargmentadapter，当viewpager里是fargment的话更方便

1.抽取BaseActivity   管理所有activity 方便退出

1. public class BaseActivity extends ActionBarActivity {
   	// 管理运行的所有的activity
   	public final static List<BaseActivity> mActivities = new LinkedList<BaseActivity>();//增删快
   	//使用广播也可以，如果当前Activity想退出可以，sendReceiver
   //	private KillAllReceiver receiver;
   //	private class KillAllReceiver extends BroadcastReceiver{
   //
   //		@Override
   //		public void onReceive(Context context, Intent intent) {
   //			finish();
   //		}
   //	}
   
   	@Override
   	protected void onCreate(Bundle savedInstanceState) {
   		super.onCreate(savedInstanceState);
   //		receiver=new KillAllReceiver();
   //		IntentFilter filter=new IntentFilter("com.itheima.google.killall");
   //		registerReceiver(receiver, filter);
   
   		//解决同步问题，不可以添加的时候删除
   		synchronized (mActivities) {
   			mActivities.add(this);
   		}
   		init();//定义几个方法子类去实现，代码不臃肿，这个是初始化view前的操作
   		initView();
   		initActionBar();
   	}
   	@Override
   	protected void onDestroy() {
   		super.onDestroy();
   		synchronized (mActivities) {
   			mActivities.remove(this);
   		}
   //		if(receiver!=null){
   //			unregisterReceiver(receiver);
   //			receiver=null;
   //		}
   	}
   	public void killAll() {
   		// 复制了一份mActivities 集合，因为不能在操作mActivities 的时候去遍历，就是这样复制的
   		List<BaseActivity> copy;
   		synchronized (mActivities) {
   			copy = new LinkedList<BaseActivity>(mActivities);
   		}
   		for (BaseActivity activity : copy) {
   			activity.finish();
   		}
   		// 杀死当前的进程
   		android.os.Process.killProcess(android.os.Process.myPid());
   	}
   	protected void initActionBar() {
   	}
   	protected void initView() {
   	}
   	protected void init() {
   	}
   }

2.MainActivity 

public class MainActivity extends BaseActivity implements
		OnQueryTextListener {
	private DrawerLayout mDrawerLayout;
	private ActionBarDrawerToggle drawerToggle;
	private ViewPager mViewPager;
	private PagerTabStrip pager_tab_strip;
	private String[] tab_names;  // 标签的名字
	@Override
	protected void initActionBar() {
		ActionBar actionBar = getSupportActionBar();
		actionBar.setDisplayHomeAsUpEnabled(true);
		actionBar.setHomeButtonEnabled(true);
		drawerToggle = new ActionBarDrawerToggle(this,
				mDrawerLayout, R.drawable.ic_drawer_am, R.string.open_drawer,
				R.string.close_drawer){
					@Override
					public void onDrawerClosed(View drawerView) {
						super.onDrawerClosed(drawerView);
						Toast.makeText(getApplicationContext(), "抽屉关闭了", 0).show();
					}
					@Override
					public void onDrawerOpened(View drawerView) {
						super.onDrawerOpened(drawerView);
						Toast.makeText(getApplicationContext(), "抽屉打开了", 0).show();
					}

		};
		mDrawerLayout.setDrawerListener(drawerToggle);
		//  让开关和actionbar建立关系
		drawerToggle.syncState();

	}
	@Override
	protected void init() {
		tab_names = UiUtils.getStringArray(R.array.tab_names);
	}

	@Override
	protected void initView() {
		setContentView(R.layout.activity_main);
		mDrawerLayout = (DrawerLayout) findViewById(R.id.dl);
		mViewPager=(ViewPager) findViewById(R.id.vp);
		pager_tab_strip=(PagerTabStrip) findViewById(R.id.pager_tab_strip);
		//  设置标签下划线的颜色
		pager_tab_strip.setTabIndicatorColor(getResources().getColor(R.color.indicatorcolor));

		mViewPager.setAdapter(new MainAdpater(getSupportFragmentManager()));
		//sendBroadcast(new Intent("com.itheima.google.killall"));
		//Log.i(tag, msg)
	}
	private class MainAdpater extends FragmentStatePagerAdapter{
		public MainAdpater(FragmentManager fm) {
			super(fm);
		}
		// 每个条目返回的fragment
		//  0
		@Override
		public Fragment getItem(int position) {
			//  通过Fragment工厂  生产Fragment
			return FragmentFactory.createFragment(position);
		}
		// 一共有几个条目
		@Override
		public int getCount() {
			return tab_names.length;
		}
		// 返回每个条目的标题
		@Override
		public CharSequence getPageTitle(int position) {
			return tab_names[position];
		}

	}
	@SuppressLint("NewApi")
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.activity_main, menu);
		// 如果运行的环境 (部署到什么版本的手机 )大于3.0
		if (android.os.Build.VERSION.SDK_INT > 11) {
			SearchView searchView = (SearchView) menu.findItem(
					R.id.action_search).getActionView();
			searchView.setOnQueryTextListener(this);// 搜索的监听
		}
		return true;
	}

	/** 处理actionBar菜单条目的点击事件 */
	public boolean onOptionsItemSelected(MenuItem item) {
		if (item.getItemId() == R.id.action_search) {
			Toast.makeText(getApplicationContext(), "搜索", 0).show();
		}
		return drawerToggle.onOptionsItemSelected(item)|super.onOptionsItemSelected(item);
	}
	// 当搜索提交的时候
	@Override
	public boolean onQueryTextSubmit(String query) {
		Toast.makeText(getApplicationContext(), query, 0).show();
		return true;
	}
	// 当搜索的文本发生变化
	@Override
	public boolean onQueryTextChange(String newText) {
		return true;
	}
}

　　

3.UiUtils 

1. public class UiUtils {
   	/**
   	 * 获取到字符数组
   	 * @param tabNames  字符数组的id
   	 */
   	public static String[] getStringArray(int tabNames) {
   		return getResource().getStringArray(tabNames);
   	}
   	public static Resources getResource() {
   		return BaseApplication.getApplication().getResources();
   	}
   
   	/** dip转换px */
   	public static int dip2px(int dip) {
   		final float scale = getResource().getDisplayMetrics().density;
   		return (int) (dip * scale + 0.5f);
   	}
   	/** pxz转换dip */
   	public static int px2dip(int px) {
   		final float scale = getResource().getDisplayMetrics().density;
   		return (int) (px / scale + 0.5f);
   	}
   }
   

这样定义数组：string.xml里

1. <string-array name="tab_names">
2. <item>首页</item>
3. <item>应用</item>
4. <item>游戏</item>
5. <item>专题</item>
6. <item>分类</item>
7. <item>排行</item>
8. </string-array>

4.FragmentFactory

1. public class FragmentFactory {
   	private static Map<Integer, Fragment> mFragments = new HashMap<Integer, Fragment>();
   	public static Fragment createFragment(int position) {
   		Fragment fragment = null;
   		fragment = mFragments.get(position);  //在集合中取出来Fragment
   		if (fragment == null) {  //如果再集合中没有取出来 需要重新创建
   			if (position == 0) {
   				fragment = new HomeFragment();
   			} else if (position == 1) {
   				fragment = new AppFragment();
   			} else if (position == 2) {
   				fragment = new GameFragment();
   			} else if (position == 3) {
   				fragment = new SubjectFragment();
   			} else if (position == 4) {
   				fragment = new CategoryFragment();
   			} else if (position == 5) {
   				fragment = new TopFragment();
   			}
   			if (fragment != null) {
   				mFragments.put(position, fragment);// 把创建好的Fragment存放到集合中缓存起来
   			}
   		}
   		return fragment;
   	}
   }
   

   　　

通过这样获取上下文

/**
 * 代表当前应用程序
 * @author itcast
 *
 */
public class BaseApplication extends Application {
	private static BaseApplication application;
	@Override
	public void onCreate() {
		super.onCreate();
		application=this;

	}
	public static Context getApplication() {
		return application;
	}
}