ios - 将值传递给 UIView 返回 nil

Question

我有一个 UIViewController GamePlayViewController 和一个 UIView JoystickView。

我正在尝试为 JoystickView 设置浮点值。

在GamePlayViewController.m

JoystickView *joystick = [[JoystickView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];

joystick.velocity = 123.0f;
[self.view addSubview:joystick];

在JoystickView.h

@property(nonatomic) float velocity;

.m

@synthesize velocity;
-(id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
    NSLog(@"%f", velocity);        //output is 0
}
return self;
}

我错过了什么？

Answer 1

您可以通过创建 initWithFrameAndVelocity 方法来覆盖 initWithFrame

-(id)initWithFrame:(CGRect)frame andVelocity:(float)v {
self = [super initWithFrame:frame];
if (self) {
velocity = v;
    NSLog(@"%f", velocity);        //output is 0
}
return self;
}