CS51 - Fall 2009 - Lecture 25
- Recall, the key private member variables
- private int MAX_OBJECTS = 25;
- private int SIZE = 100; // dimensions of the objects
- private DrawableInterface shapes = new DrawableInterface[MAX_OBJECTS];
- Recall, our onMousePress method has four options
- add a new item
- move an item
- recolor the item
- delete an item
- How do we add a new item?
- figure out the shape from the menu and create a new shape
- figure out the color from the menu and set color
- add to our shapes array
- How do we implement move?
- need to figure out which shape we've clicked on
- write a function int getIndexOf(Location point)
- iterates through our list and calls .contains() on the points
- now, that we know what we've clicked on, how do we move it?
- private DrawableInterface selected;
- set selected = null at beginning of onMousePress
- if it's a move, set selected = the object selected
- onMouseDrag can move the object pointed to by selected
- how do we deal with overlapping shapes?
- if we click on an overlapping spot, went to move the one on front
- when we're adding things, how is this order preserved?
- elements later in the list are more "in front" than earlier
- search the array from the back forward
- When we move an item, we need to preserve this functionality
- move the item to the front of the canvas
- move the item to the back of the list and shift everything else down
- how can we implement this?
- remove the item we want to move to the end
- removeEltWithIndex(int index)
- then put it at the end
- How do we implement Recolor? (should be easy now)
- recolor that objects
- How do we implement delete? (should be easy now)
- remove the object from the canvas
Show textStatDebug demo
- set breakpoints
- step over
- step into
Other misc. array things
- What happens here?
int numbers = new array;
int currentIndex = 0;
currentIndex = 10;
- ArrayOutOfBounds exception