B4A初始化定时器，并指定事件名和触发间隔时间(毫秒).

Dim Data() As Byte
Data = "Some string".GetBytes("UTF8")
IndexOf (SearchFor As String) As Int
返回查找到的第一个匹配字符串的位置
如果未找到，返回-1
IndexOf2 (SearchFor As String, Index As Int) As Int
返回查找到的第一个匹配字符串的位置
从指定的索引开始查找
如果未找到，返回-1
Length As Int
返回字符串的长度
Replace (Target As String, Replacement As String) As String
返回一个覆盖了指定字符串的新字符串
StartsWith (Prefix As String) As Boolean
Returns true if this string starts with the given Prefix.
如果字符串以指定的字符串Prefix为前缀，返回true
SubString (BeginIndex As Int) As String
Returns a new string which is a substring of the original string.
返回一个从指定位置截取的新字符串
新的字符串包含指定的字符位置，直至字符串结尾
例如:
"012345".SubString(2) '返回 "2345"
SubString2 (BeginIndex As Int, EndIndex As Int) As String
返回一个从指定位置截取的新字符串
新的字符串包含指定的起始字符位置，不包含结尾字符位置
例如:
"012345".SubString2(2, 4) '返回 "23"
ToLowerCase As String
将字符串转换为小写
ToUpperCase As String
将字符串转换为大写
Trim As String
去掉字符串前端和尾端的空格
StringBuilder
StringBuilder是一个可变的字符串，不同于通常的字符串不可变
StringBuilder适合用于将多个字符串合并
下面的代码演示了通过StringBuilder提高性能
Dim start As Long
start = DateTime.Now
'Regular string
Dim s As String
For i = 1 To 5000
s = s & i
Next
Log(DateTime.Now - start)
'StringBuilder
start = DateTime.Now
Dim sb As StringBuilder
sb.Initialize
For i = 1 To 5000
sb.Append(i)
Next
Log(DateTime.Now - start)
在真实设备上，第一个循环需要20s,第二个循环少于10s
函数StringBuilder.ToString可以将对象转换为一个字符串
事件:
无
成员:
Append (Text As String) As StringBuilder
Initialize
Insert (Offset As Int, Text As String) As StringBuilder
IsInitialized As Boolean
Length As Int [只读]
Remove (StartOffset As Int, EndOffset As Int) As StringBuilder
ToString As String
成员描述:
Append (Text As String) As StringBuilder
在结尾连接指定的字符串
返回同一个对象，你可以多次调用
例如:
sb.Append("First line").Append(CRLF).Append("Second line")
Initialize
初始化对象
例如:
Dim sb As StringBuilder
sb.Initialize
sb.Append("The value is: ").Append(SomeOtherVariable).Append(CRLF)
Insert (Offset As Int, Text As String) As StringBuilder
从指定的位置插入字符串
IsInitialized As Boolean
Length As Int [只读]
返回对象中的字符数
Remove (StartOffset As Int, EndOffset As Int) As StringBuilder
移除指定的字符串
StartOffset - 第一个将被移除的字符索引.
EndOffset - 结尾字符索引. 这个字符不会被移除
ToString As String
将对象转换为string
Timer
定时器对象
推荐在一个时间较长的循环中使用Timer，因为他运行UI线程调度事件和消息
注意如果UI线程忙，timer事件将不会立即被触发(除非你使用了DoEvents)
timer的Enable属性默认是false，需要改成true才能开始工作
Timer 事件在activity 活动暂停或一个阻止对话框可见时不会被触发，Timers 需要在Process_Globals中声明
否则你可能会在activity 重新创建时产生多个timers过程
如果activity 暂停，建议将timer也暂停，在activity恢复时重新开启，这样能节省CPU和电量损耗
事件:
Tick
成员:
Enabled As Boolean
Initialize (EventName As String, Interval As Long)
Interval As Long
成员描述:
Enabled As Boolean
Initialize (EventName As String, Interval As Long)
初始化定时器，并指定事件名和触发间隔时间(毫秒).
注意:这个对象一定要在Process_Globals中声明
例如:
Timer1.Initialize("Timer1", 1000)
Timer1.Enabled = True
Sub Timer1_Tick
'Handle tick events
End Sub
Interval As Long
获取或设置定时器的触发间隔(毫秒)