Apple Newton Utilities Uživatelská příručka stáhnout pdf (Strana 415)

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CHAPTER 10

Recognition: Advanced Topics

Using Advanced Topics in Recognition 10-39

The cells in this example template use ﬁlters deﬁned by the format and filters

slots to restrict input to valid values.

The

format slot speciﬁes the valid input for each position in the comb view. Each

character in the

format string is an index into the filters array. In this example,

the ﬁrst position in the comb view is ﬁltered by the element 1 of the

filters

array, which is the

digits1 template; the second position is ﬁltered by element 0

of the ﬁlters array, which is the

digits template.

You can write-protect any position in the comb view by placing an underscore (

in the appropriate position in the

format string. In this example, the string positions

that display slashes between the digits of the date ﬁeld do not allow input. These

are indicated by the underscores at corresponding positions in the

format string.

The

text slot is not used by protoCharEdit views, but may be used as a

default value by optional

SetupString and CleanupString methods that your

template supplies.

Note that the template itself does not restrict any values unnecessarily. For example,

it is not wise to restrict date values according to the value of the month, because the

user might enter the date before the month or the month value might not be

recognized correctly. Instead, you can deﬁne a

CleanupString function that

examines the input string and indicates an error condition or modiﬁes the string.

The following code fragment provides examples of typical

SetupString and

CleanupString functions.

myTemplate := {

format:"0000001",

string:" 0",

filters: [kMyDigitsOrSpace, kMyDigits],

SetupString: func(str) begin

// pad string to 5 digits

if StrLen(str) < 7 then

StrMunger(str,0,0,string,0,7-StrLen(str));

str;

end,

CleanupString: func(str) begin

// replace spaces with zeros

StrReplace(str, " ", "0", nil);

// trim leading zeros

str := NumberStr(StringToNumber(str));

str;

end,

};

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