I'm stumped. I don't have any errors or even warnings. I set a breakpoint at the line that calls it, and the program stops there, but when I set a breakpoint inside the actual code for that selector, the program doesn't stop. The selector I'm concerned with is toggleCellAtX:Y:
. Here's SPPuzzle.m:
我很难过。我没有任何错误甚至警告。我在调用它的行上设置了一个断点,程序在那里停止,但是当我在该选择器的实际代码中设置断点时,程序不会停止。我关心的选择器是toggleCellAtX:Y:。这是SPPuzzle.m:
#import "SPPuzzle.h"
@implementation SPPuzzle
- (id)init
{
self = [super init];
if (self) {
int x, y;
for (y=0; y<3; y++)
for (x=0; x<3; x++) {
cells[x][y] = FALSE;
}
}
return self;
}
- (BOOL)cellOnAtX:(int)x Y:(int)y {
return cells[x][y];
}
- (void)toggleCellAtX:(int)x Y:(int)y {
cells[x][y] = !cells[x][y]; // Breakpoint here doesn't stop program.
}
@end
And here's SPPuzzleView.m:
这是SPPuzzleView.m:
#import "SPPuzzleView.h"
@implementation SPPuzzleView
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self) {
puzzleInstance = [[SPPuzzle alloc] init];
}
return self;
}
- (void)drawRect:(NSRect)dirtyRect
{
int x, y;
for (y=0; y<3; y++)
for (x=0; x<3; x++) {
if ([puzzleInstance cellOnAtX:x Y:y]) {
[[NSColor greenColor] set];
} else {
[[NSColor redColor] set];
}
[[NSBezierPath bezierPathWithRect:NSMakeRect(100*x, 100*y, 100, 100)] fill];
[[NSColor blackColor] set];
[[NSBezierPath bezierPathWithRect:NSMakeRect(100*x, 100*y, 100, 100)] stroke];
}
}
- (void)mouseDown:(NSEvent *)theEvent {
int x = (int)[theEvent locationInWindow].x / 100;
int y = (int)[theEvent locationInWindow].y / 100;
[puzzleInstance toggleCellAtX:x Y:y]; // Breakpoint here does stop program.
[self setNeedsDisplay:TRUE];
}
@end
I added comments to show where the breakpoints are. What am I doing wrong?
我添加了评论以显示断点的位置。我究竟做错了什么?
By the way, I used Step Into on the invocation of the method, but it just goes to the next line ([self setNeedsDisplay:TRUE];
).
顺便说一句,我在调用方法时使用了Step Into,但它只是进入下一行([self setNeedsDisplay:TRUE];)。
1 个解决方案
#1
2
puzzleInstance
is probably nil
(0x0
in the watch list, as you noted: nil
is just another fancy name for the memory address 0
). This would be the case if you instantiated your SPPuzzleView
from a XIB file, because the loading mechanism calls initWithCoder:
(then awakeFromNib
) instead of initWithFrame:
, leaving your puzzleInstance
uninitialized.
puzzleInstance可能是nil(监视列表中的0x0,正如您所说:nil只是内存地址0的另一个奇特名称)。如果您从XIB文件中实例化SPPuzzleView,就会出现这种情况,因为加载机制会调用initWithCoder :(然后是awakeFromNib)而不是initWithFrame :,使您的puzzleInstance保持未初始化状态。
#1
2
puzzleInstance
is probably nil
(0x0
in the watch list, as you noted: nil
is just another fancy name for the memory address 0
). This would be the case if you instantiated your SPPuzzleView
from a XIB file, because the loading mechanism calls initWithCoder:
(then awakeFromNib
) instead of initWithFrame:
, leaving your puzzleInstance
uninitialized.
puzzleInstance可能是nil(监视列表中的0x0,正如您所说:nil只是内存地址0的另一个奇特名称)。如果您从XIB文件中实例化SPPuzzleView,就会出现这种情况,因为加载机制会调用initWithCoder :(然后是awakeFromNib)而不是initWithFrame :,使您的puzzleInstance保持未初始化状态。