PKG_TARGETS:=bin
define Package/$(PK_NAME)/install
$(1) 为$(BINDIR)/$(PK_NAME)，如bin/goldfish/goldfish-qemu
endef
并且不能反复编译make xx/install，只会在总体make时才会编译
而PKG_TARGETS:=ipkg
define Package/$(PK_NAME)/install
$(1) 为staging/root_xxx
endef
做机房收费系统时，要用到组合查询，其界面如下：我开始想的特别的复杂，可以这三个里随便选一个查询条件查询，也可在这三个中任选两个，也可三个都选，特别地麻烦，为什么不让他选第二个查询条件时必须选第一个呢，这样就简单了很多。
我开始想的一种方法，代码如下：
Dim strSQL As String Dim strA As String, strB As String, strC As String strSQL = "select * from student where "
'判断“字段名”，“操作符”，“要查询内容”是否都选了 If Not Trim(cmbField(0).Text = "") Then If Trim(cmbOperator(0).Text = "") Then MsgBox "请选择操作符！", vbOKOnly, "警告!" cmbOperator(0).SetFocus Exit Sub Else If Trim(txtInquire(0).Text = "") Then MsgBox "请输入查询内容!", vbOKOnly, "警告!" txtInquire(0).SetFocus Exit Sub End If End If blnMark(0) = True End If '判断“字段名”，“操作符”，“要查询内容”是否都选了 If Not Trim(cmbField(1).Text = "") Then If Trim(cmbOperator(1).Text = "") Then MsgBox "请选择操作符！", vbOKOnly, "警告!" cmbOperator(1).SetFocus Exit Sub Else If Trim(txtInquire(1).Text = "") Then MsgBox "请输入查询内容!", vbOKOnly, "警告!" txtInquire(1).SetFocus Exit Sub End If End If blnMark(1) = True End If
'GetStringA,B是自定义的一个函数，将汉字替代为对应的字符，“Card--卡号” strA = GetStringA(cmbField(0).Text) & Trim(cmbOperator(0).Text) & Trim(txtInquire(0).Text) strB = GetStringB(cmbCombination(0).Text) & GetStringA(cmbField(1).Text) & Trim(cmbOperator(1).Text) & Trim(txtInquire(1).Text) strC = GetStringB(cmbCombination(1).Text) & GetStringA(cmbField(2).Text) & Trim(cmbOperator(2).Text) & Trim(txtInquire(2).Text)
'看选择了什么查询条件 If blnMark(0) = False Then MsgBox "请选择查询条件！", vbOKOnly, "警告!" Exit Sub Else strSQL = strSQL & strA If blnMark(1) = True Then strSQL = strSQL & strB If blnMark(2) = True Then strSQL = strSQL & strC
End If
End If
End If
还有一种方法，不用逻辑考虑，“select * from 表名 where cardNo=1001 ”和“select * from 表名 where cardNo=1001 and 1=1 and1=1”是一样的效果，所以我们就不用选择了什么查询条件了，让查询条件默认是“1=1”，如果选择了什么查询条件就将“1=1”替换为查询条件即可，这样就简单了很多。
Dim strSQL As String
Dim blnMark(4) As Boolean
Dim strFieldA As String
Dim strFieldB As String
Dim strFieldC As String
Dim strOperatorA As String
Dim strOperatorB As String
Dim strOperatorC As String
Dim strValueA As String
Dim strValueB As String
Dim strValueC As String
Dim strRelationA As String
Dim strRelationB As String
strRelationA = "and"
strRelationB = "and"
'给定默认值
strFieldB = "1"
strOperatorB = "="
strValueB = "1"
strFieldC = "1"
strOperatorC = "="
strValueC = "1"
'判断“字段名”，“操作符”，“要查询内容”是否都选了
If Not Trim(cmbField(0).Text = "") Then
If Trim(cmbOperator(0).Text = "") Then
MsgBox "请选择操作符！", vbOKOnly, "警告!"
cmbOperator(0).SetFocus
Exit Sub
Else
If Trim(txtInquire(0).Text = "") Then
MsgBox "请输入查询内容!", vbOKOnly, "警告!"
txtInquire(0).SetFocus
Exit Sub
End If
End If
blnMark(0) = True
'将默认值替换为查询条件
strFieldA = GetStringA(cmbField(0).Text)
strOperatorA = Trim(cmbOperator(0).Text)
strValueA = Trim(txtInquire(0).Text)
End If
'判断“字段名”，“操作符”，“要查询内容”是否都选了
If Not Trim(cmbField(1).Text = "") Then
If Trim(cmbOperator(1).Text = "") Then
MsgBox "请选择操作符！", vbOKOnly, "警告!"
cmbOperator(1).SetFocus
Exit Sub
Else
If Trim(txtInquire(1).Text = "") Then
MsgBox "请输入查询内容!", vbOKOnly, "警告!"
txtInquire(1).SetFocus
Exit Sub
End If
End If
blnMark(1) = True
'将默认值替换为查询条件
strRelationA = GetStringB(cmbCombination(0).Text)
strFieldB = GetStringA(cmbField(1).Text)
strOperatorB = Trim(cmbOperator(1).Text)
strValueB = Trim(txtInquire(1).Text)
End If
'判断“字段名”，“操作符”，“要查询内容”是否都选了
If Not Trim(cmbField(2).Text = "") Then
If Trim(cmbOperator(2).Text = "") Then
MsgBox "请选择操作符！", vbOKOnly, "警告!"
cmbOperator(2).SetFocus
Exit Sub
Else
If Trim(txtInquire(2).Text = "") Then
MsgBox "请输入查询内容!", vbOKOnly, "警告!"
txtInquire(2).SetFocus
Exit Sub
End If
End If
blnMark(2) = True
'将默认值替换为查询条件
strRelationB = GetStringB(cmbCombination(1).Text)
strFieldC = GetStringA(cmbField(2).Text)
strOperatorC = Trim(cmbOperator(2).Text)
strValueC = Trim(txtInquire(2).Text)
End If
'判断是否选择了查询条件
If blnMark(0) = False Then
MsgBox "请选择查询条件！", vbOKOnly, "警告!"
Exit Sub
End If
strSQL = "select * from student_Info where " + strFieldA + strOperatorA + Add(strValueA) + " " + strRelationA + " " + strFieldB + strOperatorB + Add(strValueB) + " " + strRelationB + " " + strFieldC + strOperatorC + Add(strValueC)
原本要复杂的拼凑SQL语句，现在只要一条SQL语句就搞定，不用拼凑了，选择了查询语句就替换掉他的默认值，没有就将让他为默认值“1=1”。
最近在做一个LBS的应用，需要用到两点间的距离，百度地图、google地图提供了这样的api，但对于我这样只需要两点间距离的来说，为了这个引用一个库就有点杀鸡用宰牛刀。记录下方法：
private const double EARTH_RADIUS = 6378.137;
private static double rad(double d)
{
return d * Math.PI / 180.0;
}
public static double GetDistance(double lat1, double lng1, double lat2, double lng2)
{
double radLat1 = rad(lat1);
double radLat2 = rad(lat2);
double a = radLat1 - radLat2;
double b = rad(lng1) - rad(lng2);
double s = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) +
Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2)));
s = s * EARTH_RADIUS;
s = Math.Round(s * 10000) / 10000;
return s;
}