Inside Macintosh: Files
You can use the standard dialog boxes provided by the Standard File Package to prompt the user for the name of a file to open or a filename and location to use when saving a document. Use StandardGetFile to present the standard interface when opening a file and StandardPutFile to present the standard interface when saving a file.
Listing 3-1 illustrates how your application can use StandardGetFile to elicit a file specification after the user chooses Open from the File menu.
Listing 1 Handling the Open menu command
FUNCTION DoOpenCmd: OSErr;
VAR
myReply: StandardFileReply; {Standard File reply record}
myTypes: SFTypeList; {types of files to display}
myErr: OSErr;
BEGIN
myTypes[0] := 'TEXT'; {display text files only}
StandardGetFile(NIL, 1, myTypes, myReply);
IF myReply.sfGood THEN
myErr := DoOpenFile(myReply.sfFile)
ELSE
myErr := UsrCanceledErr;
DoOpenCmd := myErr;
END;
If the user dismisses the dialog box by clicking the Open button, the reply record field myReply.sfGood is set to TRUE ; in that case, the function defined in Listing 3-1 calls the application-defined function DoOpenFile , passing it the file system specification record contained in the reply record. For a sample definition of the DoOpenFile function, see the chapter "Introduction to File Management" in this book.
The third parameter to StandardGetFile is a list of file types that are to appear in the list of files and folders; the second parameter is the number of items in that list of file types. The list of file types is of type SFTypeList .
TYPE SFTypeList = ARRAY[0..3] OF OSType;
If you need to display more than four types of files, you can define a new data type that is large enough to hold all the types you need. For example, you can define the data type MyTypeList to hold ten file types:
TYPE MyTypeList = ARRAY[0..9] OF OSType;
MyTListPtr = ^MyTypeList;
Listing 3-2 shows how to call StandardGetFile using an expanded type list.
Listing 2 Specifying more than four file types
FUNCTION DoOpenCmd: OSErr;
VAR
myReply: StandardFileReply; {Standard File reply record}
myTypes: MyTypeList; {types of files to display}
myErr: OSErr;
BEGIN
myTypes[0] := 'TEXT'; {first file type to display}
{Put other assignments here.}
myTypes[9] := 'RTFT'; {tenth file type to display}
StandardGetFile(NIL, 1, MyTListPtr(myTypes)^, myReply);
IF myReply.sfGood THEN
myErr := DoOpenFile(myReply.sfFile)
ELSE
myErr := UsrCanceledErr;
DoOpenCmd := myErr;
END;
To display all file types in the dialog box, pass -1 as the second parameter. Invisible files and folders are not shown in the dialog box unless you pass -1 in that parameter. If you pass -1 as the second parameter when calling CustomGetFile , the dialog box also lists folders; this is not true when you call StandardGetFile .
The first parameter passed to StandardGetFile is the address of a file filter function, a function that helps determine which files appear in the list of files to open. (In Listing 3-1 , this address is NIL , indicating that all files of the specified type are to be listed.) See "Writing a File Filter Function" for details on defining a filter function for use with StandardGetFile .