Cocoa/Obj-C - Open file when dragging it to application icon

Question

Currently there is a button on my app inteface which allow to open a file, here is my open code:

In my app.h:

- (IBAction)selectFile:(id)sender;
<         


        

Answer 1

First add the proper extensions to CFBundleDocumentTypes inside the .plist file.

Next implement the following delegates:
- application:openFile: (one file dropped)
- application:openFiles: (multiple files dropped)

Reference:
NSApplicationDelegate Protocol Reference

Response to comment:

Step by step example, hopefully it makes everything clear :)

Add to the .plist file:

 CFBundleDocumentTypes
        
            
                CFBundleTypeExtensions
                
                    xml
                
                CFBundleTypeIconFile
                application.icns
                CFBundleTypeMIMETypes
                
                    text/xml
                
                CFBundleTypeName
                XML File
                CFBundleTypeRole
                Viewer
                LSIsAppleDefaultForType
                
            
        

Add to ...AppDelegate.h

- (BOOL)processFile:(NSString *)file;
- (IBAction)openFileManually:(id)sender;

Add to ...AppDelegate.m

- (IBAction)openFileManually:(id)sender;
{
    NSOpenPanel *openPanel  = [NSOpenPanel openPanel];
    NSArray *fileTypes = [NSArray arrayWithObjects:@"xml",nil];
    NSInteger result  = [openPanel runModalForDirectory:NSHomeDirectory() file:nil types:fileTypes ];
    if(result == NSOKButton){
        [self processFile:[openPanel filename]];
    }
}

- (BOOL)application:(NSApplication *)theApplication openFile:(NSString *)filename
{
    return [self processFile:filename];
}

- (BOOL)processFile:(NSString *)file
{
    NSLog(@"The following file has been dropped or selected: %@",file);
    // Process file here
    return  YES; // Return YES when file processed succesfull, else return NO.
}