子类NSView来改变背景颜色 [英] Subclass NSView to change background color

问题描述

我想更改自定义视图的背景颜色。我有一个子类NSView像这样：

I want to change the background color of a custom view. I have a subclass NSView something like that:

#import <Cocoa/Cocoa.h>
@interface CustomBGView : NSView {
NSColor myColor; 
} @end

和.m

  @implementation CustomBGView

  - (void)drawRect:(NSRect)rect
  {
    [myColor set];
    NSRectFill([self bounds]);
  }

  - (void)changeColor:(NSColor*) aColor
 {
    myColor = aColor;
 }

changeColor方法用于在应用程序控制器中更改颜色。我还为自定义视图定义了一个IBOutlet，在IB中称为myView binded。

The changeColor method is for change color in the app controller. I also define a IBOutlet for the custom view called myView binded in IB.

问题是当我在应用控制器中使用changeColor时：

The problem is when I use changeColor in the app controller like this:

[myView changeColor: [NSColor colorWithCalibratedRed:0.5 green:0.5 blue:0.5 alpha:1.0]];

有一个程序接收信号：EXC_BAD_ACCESS。如果我改用这样的东西：

There is a 'Program received signal: "EXC_BAD_ACCESS". If I use instead something like this:

[myView changeColor: [NSColor whiteColor]];

可以正常工作。

问题在哪里？提前感谢

谢谢Chuck！现在用retain工作正常。

Thanks Chuck! Now with "retain" works fine.

为什么它在一个案例中没有保留（[myView changeColor：[NSColor whiteColor]];）而不在其他???

And why it works without retain in one case ([myView changeColor: [NSColor whiteColor]];) and not in the other???

推荐答案

您在实例变量中存储了 changeColor：的参数， ，所以你不拥有它，它认为它可以消失。

You're storing the argument to changeColor: in an instance variable, but not retaining it, so you don't own it and it thinks it can go away.

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