13-7-5 android Tabhost功能实现

开始使用了一个Activity做界面切换，采用visible、gone写法，感觉太麻烦了。

layoutHousehold.setVisibility(View.GONE);
layoutCamera.setVisibility(View.GONE);
layoutEnvironment.setVisibility(View.GONE);
layoutMsg.setVisibility(View.GONE);
layoutSetting.setVisibility(View.GONE);
layoutLight.setVisibility(View.VISIBLE);

一般使用MainActivity集成Activity类的时候，通过setContentView(Layout)设计当前的图层，线程称为主线程，当你在定一个类的时候你是不能更改当前的UI的，也就是说一个Activity UI界面对应一个类，不能使用另外的类进行更改，毕竟更新UI需要主线程来完成，新的类不再主线程中（个人观点）。

那么怎么通过导航栏做Activity切换？使用ViewGroup中的TabHost。

效果：

1、这里我使用了Tabhost：

这里导航栏使用setIndicator不是特别灵活，还有就是自己对setIndicator（View）中的view理解的不对，经常出现让我移除图层的错误，所以采用单击监听事件：

	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main1);
		tabhost = (TabHost) this.findViewById(android.R.id.tabhost);//获取当前的tabhost,注册

		tabhost.setup();
		tabhost.addTab(tabhost.newTabSpec("tab1")
				.setIndicator("tab1")
				.setContent(new Intent(this, light.class)));
		tabhost.addTab(tabhost.newTabSpec("tab2")
				.setIndicator("tab2")
				.setContent(new Intent(this, Household.class)));
		tabhost.addTab(tabhost.newTabSpec("tab3")
				.setIndicator("tab3")
				.setContent(new Intent(this, Camera.class)));
		tabhost.addTab(tabhost.newTabSpec("tab4")
				.setIndicator("tab4")
				.setContent(new Intent(this, Environment.class)));
		tabhost.addTab(tabhost.newTabSpec("tab5")
				.setIndicator("tab5")
				.setContent(new Intent(this, Msg.class)));
		tabhost.addTab(tabhost.newTabSpec("tab6")
				.setIndicator("tab6")
				.setContent(new Intent(this, Setting.class)));
		tabhost.setCurrentTabByTag("tab1");
		ctrlCmd();

	}

2、事件监听与图片切换

	/***************************************
	 * 设定面板邮编图标，单击当前图标会变成绿色，同时加载当前按钮对应的activity
	 */
	public void ctrlCmd(){
		ctrlLight=(ImageView)this.findViewById(R.id.ctrl_light);
		ctrlHousehold=(ImageView)this.findViewById(R.id.ctrl_household);
		ctrlCamera=(ImageView)this.findViewById(R.id.ctrl_camera);
		ctrlEnvironment=(ImageView)this.findViewById(R.id.ctrl_environment);
		ctrlMsg=(ImageView)this.findViewById(R.id.ctrl_msg);
		ctrlSetting=(ImageView)this.findViewById(R.id.ctrl_setting);

		ctrlonclick ctrl = new ctrlonclick();
		ctrlLight.setOnClickListener(ctrl);
		ctrlHousehold.setOnClickListener(ctrl);
		ctrlCamera.setOnClickListener(ctrl);
		ctrlEnvironment.setOnClickListener(ctrl);
		ctrlMsg.setOnClickListener(ctrl);
		ctrlSetting.setOnClickListener(ctrl);
	}
	/************************************************************
	 * 做一个类用来监听按键的触发程序
	 * @author hanzhen
	 *
	 */
	class ctrlonclick implements OnClickListener{

		@Override
		public void onClick(View arg0) {
			// TODO Auto-generated method stub
			if(arg0 == ctrlLight){
				Log.i(TAG, "------>>> ctrlLight is pressed");
				ctrlLight.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_light2));
				ctrlHousehold.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_household1));
				ctrlCamera.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_camera1));
				ctrlEnvironment.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_environment1));
				ctrlMsg.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_msg1));
				ctrlSetting.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_set1));
				tabhost.setCurrentTabByTag("tab1");
			}else if(arg0 == ctrlHousehold){
				Log.i(TAG, "------>>> ctrlHousehold is pressed");
				ctrlLight.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_light1));
				ctrlHousehold.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_household2));
				ctrlCamera.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_camera1));
				ctrlEnvironment.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_environment1));
				ctrlMsg.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_msg1));
				ctrlSetting.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_set1));
				tabhost.setCurrentTabByTag("tab2");
			}else if(arg0 == ctrlCamera){
				Log.i(TAG, "------>>> ctrlCamera is pressed");
				ctrlLight.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_light1));
				ctrlHousehold.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_household1));
				ctrlCamera.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_camera2));
				ctrlEnvironment.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_environment1));
				ctrlMsg.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_msg1));
				ctrlSetting.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_set1));
				tabhost.setCurrentTabByTag("tab3");
			}else if(arg0 == ctrlEnvironment){
				Log.i(TAG, "------>>> ctrlEnvironment is pressed");
				ctrlLight.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_light1));
				ctrlHousehold.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_household1));
				ctrlCamera.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_camera1));
				ctrlEnvironment.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_environment2));
				ctrlMsg.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_msg1));
				ctrlSetting.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_set1));
				tabhost.setCurrentTabByTag("tab4");
			}else if(arg0 == ctrlMsg){
				Log.i(TAG, "------>>> ctrlMsg is pressed");
				ctrlLight.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_light1));
				ctrlHousehold.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_household1));
				ctrlCamera.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_camera1));
				ctrlEnvironment.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_environment1));
				ctrlMsg.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_msg2));
				ctrlSetting.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_set1));
				tabhost.setCurrentTabByTag("tab5");
			}else if(arg0 == ctrlSetting){
				Log.i(TAG, "------>>> ctrlSetting is pressed");
				ctrlLight.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_light1));
				ctrlHousehold.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_household1));
				ctrlCamera.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_camera1));
				ctrlEnvironment.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_environment1));
				ctrlMsg.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_msg1));
				ctrlSetting.setImageDrawable(getResources().getDrawable(R.drawable.rbtn_set2));
				tabhost.setCurrentTabByTag("tab6");

			}
		}
	}

遇上的问题：

当我做好xml的布局文件时，我使用

setContentView(R.layout.main1);

出现了错误：

07-05 08:59:02.539: W/dalvikvm(3502): threadid=1: thread exiting with uncaught exception (group=0x40a521f8)
07-05 08:59:02.564: E/AndroidRuntime(3502): FATAL EXCEPTION: main
07-05 08:59:02.564: E/AndroidRuntime(3502): java.lang.NullPointerException
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.widget.TabWidget.dispatchDraw(TabWidget.java:340)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.View.draw(View.java:10981)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.drawChild(ViewGroup.java:2887)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2489)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.drawChild(ViewGroup.java:2885)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2489)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.drawChild(ViewGroup.java:2885)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2489)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.View.draw(View.java:10981)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.drawChild(ViewGroup.java:2887)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2489)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.drawChild(ViewGroup.java:2885)
07-05 08:59:02.564: E/AndroidRuntime(3502): 	at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2489)

主要是在UI中存在TabHost必须要做处理。

super.onCreate(savedInstanceState);
setContentView(R.layout.main1);

TabHost tabhost = (TabHost) this.findViewById(android.R.id.tabhost);//获取当前的tabhost,注册

	tabhost.setup();
	tabhost.addTab(tabhost.newTabSpec("tab1")
		.setIndicator("tab1")
		.setContent(new Intent(this, light.class)));