PICKING UP DATES in Objective-C

Printer QR in Objective-C PICKING UP DATES

Figure 5-18. The part that calculates minutes and seconds is added. Now you get to aesthetics. If you look at the result of the script in Figure 5-19, the string s value indicates three hours, two minutes, and five seconds. Although the result is correct, you would like to display it as 3:02:05. What you need is a little handler that will tack on a 0 before numbers that have one digit, that is, are less than 10. The handler will take a number, in this case from 0 to 60, and will return a string consisting of two digits. If the number is ten or greater, it will be simply coerced into a string. If it is less than ten, a 0 character will be jammed in front of it. Script 5-12 shows what the handler will look like. Script 5-12. on make_two_digit(the_number) if the_number is less than 10 then set the_result to "0" & the_number else set the_result to the_number as string end if return the_result end make_two_digit You could make this handler more sophisticated and allow a number to have any number of digits, but that s up to you. Watch how you call the handler: instead of calling it on a separate line, you just embed the call into the statement that concatenates the hours, minutes, and seconds. Instead of this: set formatted_time to h as string & ":" & m & ":" & s you write the following: set formatted_time to (h as string) & ":" & make_two_digit(m) & ":" & make_two_digit(s)

You may also add a 0 to the hours value stored in the variable h, if you want. The final touch is converting the entire script into a handler. The handler will accept a single integer value and will return a string showing the formatted time. Figure 5-19 shows the final script.

Figure 5-19. The final script is made out of two handlers. The format_seconds_to_time handler takes an integer parameter and returns that number as a string formatted in hours, minutes, and seconds.

The script presented in this section woke me up every morning when I had to be in Boston for a few months. For this script to be useful, it requires two pieces of information: it needs to know what time you want to wake up and which song you want playing when you wake up. You will create a repeat loop for each one for these items, forcing the user to pick a time and then a song. What you ll also do is store these choices in properties so that the user has to pick them only if they need to be changed. Like other scripts you looked at earlier, this one is largely composed of repeat loops. Two large endless repeat loops handle all the user input. Once that s done, the script will wait in a third repeat loop until it s time for the alarm to go off. If you check the script, you ll see that it has a few other exit repeat statements that lead you out of other endless loops. These are more related to user interaction than to dates. The user interaction trick forces the user to enter a valid value into the dialog box, and this technique is explained in 12. The basic idea behind it is that you repeat indefinitely, until you manage to convert the user-entered text to the value class you want such as a number or a date, as it is in this case. Let s go over the script s major parts.

In lines 3 6, you choose the song file and extract the file s name into a variable. Note that you have the user choose a file only if the property wakeup_tune_file is set to the default setting of missing value. That means these lines will be executed only the first time the script runs. Later in the script, in lines 26, 27, and 28, you give the user a chance to change the song file. The following part, which starts on line 7 and ends on line 23, allows you to figure out and verify the wakeup time and date. You start this block with line 7, where you simply figure out tomorrow s date: set tomorrow_date to (current date) + (1 * days) You will later apply a new time to the date object stored in the tomorrow_date variable. This takes place on line 14: set wakeup_date to date requested_time of tomorrow_date Line 8 starts a repeat loop that ends on line 23. The purpose of that loop is to qualify the text the user typed as a valid date. The time the user was asked to provide has to be a time string, such as "7:00 am", that can be converted into a date. The script first stores the string the user entered in the requested_time variable. It then tries to convert this value into a date. This happens in lines 13 through 22. If the conversion is successful, AppleScript will exit the repeat loop (line 15). If the conversion fails, the try statement will capture the error, and the on error portion of the statement will be executed. Within this on error section, you start a new try statement, which is intended to allow the user to cancel. You ask the user to enter a new date, but you give them a way out this time. If the Cancel button is clicked, the display dialog command will raise a user-cancelled error. This is caught by the inner try block, which executes the return statement in its on error section, causing the script to stop. This happens on lines 19 and 20. Line 25 will then collect all the information and will use a self-dismissing dialog box to let the user know when the clock is going to play which song and allow the user to change the tune that ll play, as shown in Figure 5-20.

Figure 5-20. The script displays a dialog box that allows the user to change the song. The dialog box will give up (close by itself) after 15 seconds. Lines 24 through 32 allow the user to change the song file. Lines 33 through 35 create a loop that makes the script wait until the wakeup time is reached. The repeat until loop statement checks to see whether the current date is the same as or later than the wakeup date. If it is, the loop exits automatically; otherwise, it executes the delay command to wait ten seconds before trying again. The final part of the script starts on line 36 and ends on line 43. This tells the QuickTime Player application to open the chosen music file and play it loudly. Script 5-13 shows the script in its entirety.