TabHost生成后会向内添加TabSpec以形成选项栏:
如果是继承的TabActivity类:
1. tabhost = getTabHost();
2. "1" ).setIndicator( "TAB 1"
3. 0
如果是直接继承Activity类:
1. tabhost = (TabHost) findViewById(R.id.tabhost);
2. tabhost.setup();
3. "1" ).setIndicator( "TAB 1"
4. 0
注意加.setup(),否则会有NullPointer的异常
main.xml:
1. < TabHost android:id = "@+id/tabhost" android:layout_width = "fill_parent" android:layout_height = "wrap_content" >
2. < LinearLayout android:orientation = "vertical" android:layout_width = "fill_parent" android:layout_height = "fill_parent" >
3. < TabWidget android:id = "@android:id/tabs" android:layout_width = "fill_parent" android:layout_height = "fill_parent" />
4. < FrameLayout android:id = "@android:id/tabcontent" android:layout_width = "fill_parent" android:layout_height = "fill_parent" >
5. < TextView android:id = "@+id/text1" android:layout_width = "wrap_content" android:layout_height = "wrap_content" />
6. </ FrameLayout >
7. </ LinearLayout >
8. </ TabHost >
注意:TabHost标签下的TabWidget和FrameLayout的id 是固定的,分别为"tabs"和"tabcontent"
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动态更改TabHost的选项卡头显示,有两种方法:一种比较笨而且可控性差(为 什么还要讲一会再说),一种比较简单而且可控性高,我们先说简单的那一种:
TabHost本身不提供有效的函数支持对选项卡头的动态更改,但是我们可以通过 TabHost的getTabWidget()函数得到选项卡头的View从而"曲线"更改选项卡头的属性:
1. ImageView iv = (ImageView) tabhost.getTabWidget().getChildAt(targetLocation).findViewById(android.R.id.icon);
2. TextView tv = (TextView) tabhost.getTabWidget().getChildAt(targetLocation).findViewById(android.R.id.title);
3. "XXXX"
4. iv.setImageDrawable(getResources().getDrawable(R.drawable.icon));
其中获得的ImageView即是TabHost的选项卡 头在targetLocation位置的图片的View,TextView是对应的文字的View,这样就可以对它们进行任意的改动了,注意 targetLocation从0开始
还有一种比较笨的方法:
就是自定义TabHost选项卡头的Layout,如下:
1. tabhost = getTabHost();
2. this ).inflate(R.layout.mytab, null
3. TextView targetTabLabel = (TextView) tempLayout.findViewById(R.id.tab_text);
4. "TAB 1"
5. tempLayout.removeAllViews();
6. "1"
注意要对tempLayout使用removeAllViews(),否则在将 targetTabLabel加入TabHost中时会出现java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.的异常
其中R.layout.mytab来自mytab.xml:
1. <? xml version = "1.0" encoding = "utf-8" ?>
2. < RelativeLayout xmlns:android = "http://schemas.android.com/apk/res/android"
3. android:layout_width = "wrap_content"
4. android:layout_height = "wrap_content" >
5. < TextView android:id = "@+id/tab_text"
6. android:layout_width = "wrap_content"
7. android:layout_height = "wrap_content"
8. android:gravity = "center"
9. android:textStyle = "bold"
10. android:background = "@drawable/selector_img" />
11. </ RelativeLayout >
1. <? xml version = "1.0" encoding = "utf-8" ?>
2. < selector xmlns:android = "http://schemas.android.com/apk/res/android" >
3. < item android:state_selected = "false"
4. android:drawable = "@drawable/img1" >
5. </ item >
6. < item android:state_selected = "true"
7. android:drawable = "@drawable/img2" >
8. </ item >
9. </ selector >
点击时使用Selector置换背景图片,文字的更改尚未用此方法验证,这种方法非常繁琐而且可控性太差,只能响应选择事件,且只能更改2个选项,但是之 所以讲解这种方法,是因为这里顺便讲解了如何自定义TabHost选项卡头的Layout,如果你想在UI上做出更多的花样,这个技巧是很有帮助的。