UndoManager

Adds an OnUndoHistoryChangeListener for being notified of changes to the undo manager's edit history (i.e. its undo and redo stacks). If a listener has already been added previously, this method will be a no-op. Passing null is not allowed and will result in an exception.

Returns whether there are edits that can be redone or not. If this returns false a call to redo will throw an exception.

Returns whether there are edits that can be undone or not. If this returns false a call to undo will throw an exception.

Clears the history of all currently recorded edits. After calling this method, this UndoManager will have no edits that can be undone or redone.

Redoes the next edit or throws an exception if a redo operation is not possible. It's recommended that you check whether a redo operation is available using (canRedo) before calling this method. Redoing may be unavailable if there are no edits on the redo stack or if the latest edit on the redo stack cannot be redone. When redoing an edit, the edit is moved to the internal undo stack.

Removes a previously added OnUndoHistoryChangeListener. Upon calling this method, listener will no longer be notified of any changes. If listener has not been added previously, this method will be a no-op. Passing null is not allowed, and will result in an exception.

Sets the OnAddNewEditListener for being notified when new com.pspdfkit.undo.edit.Edit are being added. This can be used to prevent edits from being added or reading edit information when they are getting added.

Undoes the last edit or throws an exception if an undo operation is not possible. It's recommended that you check whether an undo operation is available using (canUndo) before calling this method. Undoing may be unavailable if there are no edits on the undo stack or if the latest edit on the undo stack cannot be undone. When undoing an edit, the edit is moved to the internal redo stack.