Android ActionBar Tabs学习笔记

本例主要实现用Tab切换不同的Fragment，点击View显示or隐藏ActionBar，把ActionBar 设为透明，使界面更加友好，详细代码见资源里的ActionBarTabs。

ActionBar Tab主要用于Fragment之间的切换，其必须要设置ActionBar.TabListener，详细代码如下ActionBarActivity.java：

import android.app.ActionBar;
import android.app.Activity;
import android.app.FragmentTransaction;
import android.app.ActionBar.Tab;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.MotionEvent;
import android.view.Window;

public class ActionBarActivity extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		//使ActionBar变得透明
		requestWindowFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
		setContentView(R.layout.main);

		final ActionBar actionBar = getActionBar();
		actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
		// remove the activity title to make space for tabs
		actionBar.setDisplayShowTitleEnabled(false);

		AFragment aFragment = new AFragment();
		actionBar.addTab(actionBar.newTab().setText("Tab-A")
				.setTabListener(new ListenerA(aFragment))); 

		BFragment bFragment = new BFragment();
		actionBar.addTab(actionBar.newTab().setText("Tab-B")
				.setTabListener(new ListenerB(bFragment)));
	}
	//点击显示or隐藏ActionBar
	public boolean onTouchEvent(MotionEvent event){
		ActionBar bar = getActionBar();
		switch(event.getAction()){
			case MotionEvent.ACTION_UP:
				if(bar.isShowing()) bar.hide();
				else bar.show();
				break;
			default:
					break;
		}
		return true;
	}

	private class ListenerA implements ActionBar.TabListener {
		private AFragment mFragment;
		// Called to create an instance of the listener when adding a new tab
		public ListenerA(AFragment fragment) {
			mFragment = fragment;
		}
		public void onTabSelected(Tab tab, FragmentTransaction ft) {
			ft.add(R.id.fragment, mFragment, null);
		}
		public void onTabUnselected(Tab tab, FragmentTransaction ft) {
			ft.remove(mFragment);
		}
		public void onTabReselected(Tab tab, FragmentTransaction ft) {
			// do nothing }
		}
	}

	private class ListenerB implements ActionBar.TabListener {
		private BFragment mFragment;

		// Called to create an instance of the listener when adding a new tab
		public ListenerB(BFragment fragment) {
			mFragment = fragment;
		}

		public void onTabSelected(Tab tab, FragmentTransaction ft) {
			ft.add(R.id.fragment, mFragment, null);
		}

		public void onTabUnselected(Tab tab, FragmentTransaction ft) {
			ft.remove(mFragment);
		}

		public void onTabReselected(Tab tab, FragmentTransaction ft) {
			// do nothing }
		}
	}
}

其中涉及到两个Fragment，在前面Fragment的笔记中讲过，这里就不再赘述。类AFragment实现如下，BFragment实现与这类似：  

public class AFragment extends Fragment {
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		return inflater.inflate(R.layout.alayout, container, false);
		}
	}