RSBUndoManager is a lightweight helper with keyPath-based undo registration and simple memory management; built on top of NSUndoManager.
Prepare an instance of RSBUndoManager:
self.undoManager = [[RSBUndoManager alloc] init]Register an undo action before change you want to be able to undo:
- (id)init {
// ...
someObject.someKeyPath = @"oldValue"
// ...
}
- (void)onAction {
[self.undoManager appendTarget:someObject keyPath:@"someKeyPath"];
someObject.someKeyPath = @"newValue"
}Perform undo:
[self.undoManager undo];
// someObject.someKeyPath will be set to @"oldValue"You won’t need to explicitly register redo action, so if you want to perform a redo just call:
[self.undoManager redo];
// someObject.someKeyPath will be set to @"newValue"RSBUndoManager provides 3 memory warning handling policies, which can be selected by setting memoryWarningPolicy property.
RSBUndoManagerMemoryWarningPolicyNone (default) means that it will ignore memory warnings and always keep references to values in undo stack. Use it if you want to handle memory yourself.
RSBUndoManagerMemoryWarningPolicyDropHalf means RSBUndoManager will try to drop half of actions in undo stack. It's not precise though, since it's not always possible to reliably determine amount of actions in stack due to limitations of NSUndoManager.
RSBUndoManagerMemoryWarningPolicyDropAll means RSBUndoManager will drop all undo stack on memory warning. Use it if contents of undo stack are not that critical.
To run the example project, clone the repo, and run pod install from the Example directory first.
RSBUndoManager is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod "RSBUndoManager"To install it via Carthage, simply add the following line to your Cartfile:
github "rosberry/RSBUndoManager"
Anton Kormakov, anton.kormakov@rosberry.com
RSBUndoManager is available under the MIT license. See the LICENSE file for more info.