<!-- end header -->
2011年08月12日
RelativeLayout 的使用实例 类似自定义TabHost效果
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TabHost如果要自定义显示的效果,有点麻烦,而默认的样式有时候又与我们程序的风格不匹配.今天我们就用RelativeLayout来 实现与TabHost相同的功能.上效果图:
点击上面的tab,tab自身样式会改变,下面内容也会改变,功能完全与TabHost相同.
介绍一下RelativeLayout,RelativeLayout是相对布局,顾名思义,就是说里面的控件位置都是相对其他控件的位置而确定的.如上 面的效果,Tab相对于屏幕顶部对齐,底部按钮相对于屏幕底部对齐.而内容则放在顶部的Tab和底部的按钮中间.
所以所有被其他控件依赖定位的控件,必须先写,也就是说,要实现上面的效果,XML中不是从上往下写,而是先定上和下,再写中间,因为中间的内容高度,位 置都依赖于它的上下控件.
实现TabHost效果的原理也简单,点击tab时设置被点击和没被点击的的tab的背景,字体颜色即可显示点击效果.在点击事件中,用View的 removeAllViews()方法清除中间控件的所有内容,再用addView方法添加需要的内容.
下面上代码,布局XML:
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<?xml
version
=
"1.0"
encoding
=
"utf-8"
?>
<RelativeLayout
xmlns:android
=
"http://schemas.android.com/apk/res/android"
android:layout_width
=
"fill_parent"
android:layout_height
=
"fill_parent"
android:weightSum
=
"1"
android:background
=
"@color/white"
>
<LinearLayout
android:id
=
"@+id/topmenu"
android:orientation
=
"horizontal"
android:layout_alignParentTop
=
"true"
android:layout_width
=
"fill_parent"
android:layout_height
=
"40dip"
android:background
=
"@drawable/topback"
android:gravity
=
"bottom"
>
<!-- android:layout_alignParentTop 与父元素顶部是否对齐,这里true,就是把这个topmenu放屏幕顶部 -->
<LinearLayout
android:id
=
"@+id/task"
android:orientation
=
"horizontal"
android:layout_height
=
"35dip"
android:layout_width
=
"100dip"
android:background
=
"@drawable/textback"
>
<TextView
android:layout_width
=
"fill_parent"
android:id
=
"@+id/taskText"
android:layout_height
=
"fill_parent"
android:text
=
"计划"
android:gravity
=
"center"
android:textSize
=
"20sp"
android:textColor
=
"@color/white"
/>
</LinearLayout
>
<LinearLayout
android:id
=
"@+id/accounts"
android:orientation
=
"horizontal"
android:layout_height
=
"35dip"
android:layout_width
=
"100dip"
>
<TextView
android:layout_width
=
"fill_parent"
android:id
=
"@+id/accountsText"
android:layout_height
=
"fill_parent"
android:text
=
"帐号"
android:gravity
=
"center"
android:textSize
=
"20sp"
android:textColor
=
"@color/green"
/>
</LinearLayout
>
<LinearLayout
android:id
=
"@+id/sended"
android:orientation
=
"horizontal"
android:layout_height
=
"35dip"
android:layout_width
=
"100dip"
>
<TextView
android:layout_width
=
"fill_parent"
android:id
=
"@+id/sendedText"
android:layout_height
=
"fill_parent"
android:text
=
"已发"
android:gravity
=
"center"
android:textSize
=
"20sp"
android:textColor
=
"@color/green"
/>
</LinearLayout
>
</LinearLayout
>
<Button
android:id
=
"@+id/button"
android:layout_alignParentBottom
=
"true"
android:layout_width
=
"fill_parent"
android:layout_height
=
"wrap_content"
android:text
=
"底部按钮"
/>
<!-- layout_alignParentBottom 与父元素底部是否对齐,这里true,就是把这个Button放屏幕底部 -->
<!-- RelativeLayout必须先写四周的控件,再写中间的,这里先写顶部的Tab和底部的Button,再写中间的Content,因为中间的内容位置是不固定的 -->
<LinearLayout
android:id
=
"@+id/content"
android:orientation
=
"vertical"
android:layout_width
=
"fill_parent"
android:layout_height
=
"fill_parent"
android:layout_below
=
"@id/topmenu"
android:layout_above
=
"@id/button"
>
</LinearLayout
>
<!-- layout_below,当前控件放在设定控件下方 .
android:layout_above 当前控件放在设定控件上方
这里配合使用,就是放在顶部tab和底部Button的中间
-->
</RelativeLayout
>
|
程序代码:
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package
com.pocketdigi
;
import
android.app.Activity
;
import
android.os.Bundle
;
import
android.view.LayoutInflater
;
import
android.view.View
;
import
android.view.View.OnClickListener
;
import
android.widget.LinearLayout
;
import
android.widget.TextView
;
public
class
Main
extends
Activity
{
/** Called when the activity is first created. */
LinearLayout task, accounts, sended, content
;
TextView taskText, accountsText, sendedText
;
@Override
public
void
onCreate
(
Bundle savedInstanceState
)
{
super
.
onCreate
(
savedInstanceState
)
;
setContentView
(
R.
layout
.
main
)
;
task
=
(
LinearLayout
)
findViewById
(
R.
id
.
task
)
;
accounts
=
(
LinearLayout
)
findViewById
(
R.
id
.
accounts
)
;
sended
=
(
LinearLayout
)
findViewById
(
R.
id
.
sended
)
;
content
=
(
LinearLayout
)
findViewById
(
R.
id
.
content
)
;
taskText
=
(
TextView
)
findViewById
(
R.
id
.
taskText
)
;
accountsText
=
(
TextView
)
findViewById
(
R.
id
.
accountsText
)
;
sendedText
=
(
TextView
)
findViewById
(
R.
id
.
sendedText
)
;
LayoutInflater factory
=
LayoutInflater.
from
(
this
)
;
View
taskView
=
factory.
inflate
(
R.
layout
.
task
,
null
)
;
View
accountsView
=
factory.
inflate
(
R.
layout
.
accounts
,
null
)
;
View
sendedView
=
factory.
inflate
(
R.
layout
.
sended
,
null
)
;
//把三个内容视图的XML文件转化成View
content.
addView
(
taskView
)
;
//启动时默认载入taskView
task.
setOnClickListener
(
new
TabListener
(
task, taskText, taskView
)
)
;
accounts.
setOnClickListener
(
new
TabListener
(
accounts, accountsText,
accountsView
)
)
;
sended.
setOnClickListener
(
new
TabListener
(
sended, sendedText,
sendedView
)
)
;
//设置三个tab的点击监听器
}
class
TabListener
implements
OnClickListener
{
LinearLayout layout
;
TextView tv
;
View
subView
;
TabListener
(
LinearLayout layout, TextView tv,
View
subView
)
{
this
.
layout
=
layout
;
this
.
tv
=
tv
;
this
.
subView
=
subView
;
}
@Override
public
void
onClick
(
View
v
)
{
// TODO Auto-generated method stub
task.
setBackgroundDrawable
(
null
)
;
accounts.
setBackgroundDrawable
(
null
)
;
sended.
setBackgroundDrawable
(
null
)
;
taskText.
setTextColor
(
getResources
(
)
.
getColor
(
R.
color
.
green
)
)
;
accountsText.
setTextColor
(
getResources
(
)
.
getColor
(
R.
color
.
green
)
)
;
sendedText.
setTextColor
(
getResources
(
)
.
getColor
(
R.
color
.
green
)
)
;
// 全部设为未选中状态
layout.
setBackgroundResource
(
R.
drawable
.
textback
)
;
tv.
setTextColor
(
getResources
(
)
.
getColor
(
R.
color
.
white
)
)
;
// 设置选中项
content.
removeAllViews
(
)
;
//移除所有内容
content.
addView
(
subView
)
;
//添加传入的View
}
}
}
|
Strings.xml中存两个颜色值:
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|
<color
name
=
"white"
>
#ffffff
</color
>
<color
name
=
"green"
>
#0cc054
</color
>
|
三个内容视图的xml,只贴一个,另两个一样,名字不同而已:
task.xml:
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<?xml
version
=
"1.0"
encoding
=
"utf-8"
?>
<TextView
xmlns:android
=
"http://schemas.android.com/apk/res/android"
android:layout_width
=
"fill_parent"
android:layout_height
=
"fill_parent"
android:text
=
"Task"
>
</TextView
>
|
