Question

How do you change the desktop picture in cocoa/objective-c? I’ve tried using defaults but had many errors.

NSArray *args=[NSArray arrayWithObjects:@"write",@"com.apple.desktop", @"Background", @"'{default = {ImageFilePath = \"~/desktop.jpg\";};}'", nil];

NSTask *deskTask=[[NSTask alloc] init];

[deskTask setArguments: args];

[deskTask setLaunchPath:@"/usr/bin/defaults"];
[deskTask launch];
[[NSDistributedNotificationCenter defaultCenter] postNotificationName:@"com.apple.desktop" object:@"BackgroundChanged"];

The command works successfully in terminal. I don’t need anyone to tell me exactly what to do but I would like some insight.

EDIT: My OS is 10.4.11

Answer 1

I think the canonical way is to use scripting with System Events. The Applescript version is something like:

tell application "System Events"
    tell current desktop
        set picture to (whatever)
    end tell
end tell

You can use the Scripting Bridge to do it from Objective-C.