Question

我正在建立一个简单的游戏应用程序，你必须将球从另一个球移开。但是，我的代码有问题，请帮忙。当我构建并运行它时，我收到2条错误消息。我不明白问题是什么。

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
//(X speed, Y speed) vvv
pos = CGPointMake(5.0,4.0);///////// this part here I get an error message saying assigning to CGPoint * (aka 'struct CGPoint*') from incompatible type 'CGPoint' (aka 'struct CGPoint')
}

- (IBAction)start {
[startbutton setHidden:YES];
randomMain = [NSTimer scheduledTimerWithTimeInterval:(0.03) target:(self) selector:@selector(onTimer) userInfo:nil repeats:YES];

}

-(void)onTimer {
[self checkCollision];

enemy.center = CGPointMake(enemy.center.x+pos->x,enemy.center.y+pos->y);

if (enemy.center.x > 320 || enemy.center.x < 0)
    pos->x = -pos->x;

if (enemy.center.y > 480 || enemy.center.y < 0)
    pos->y = -pos->y;

}

-(void)checkCollision {

if( CGRectIntersectsRect(player.frame,enemy.frame))
{

[randomMain invalidate];
[startbutton setHidden:NO];

CGRect frame = [player frame];
frame.origin.x = 137.0f;
frame.origin.y = 326.0;
[player setFrame:frame];

CGRect frame2 = [enemy frame];
frame2.origin.x =137.0f;
frame2.origin.y = 20.0;
[enemy setFrame:frame2];

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"You Lost!" message:[NSString stringWithFormat:@"You Were Hit! Try Again"] delegate:nil cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
    [alert show];
    [alert release];

}



}

-(void)touchesMoved: (NSSet *)touches withEvent: (UIEvent *)event {
UITouch *myTOuch = [[event allTouches] anyObject];
player.center = [myTouch locationInView:self.view];      /////// Here also I get an error message saying Assigning to 'CGPoint' (aka struct CGPoint') form incompatible type 'id'

////////////////// Also with that error message is Class method '+locationalView' not found (return type defaults to 'id')
}

@end

Answer 1

在你的.h文件中，你是如何创建pos变量的？我想你添加了一个*：

CGPoint *pos;

删除*：

CGPoint pos;

编辑（感谢Jonathan Grynspan）

为什么使用 - ＆gt;运营商？我个人从未在Objective-C代码中看到它。尝试将它们更改为点：

if (enemy.center.x > 320 || enemy.center.x < 0)
    pos.x *= -1;

Answer 2

在ViewController.h文件中，编写此声明。

CGPoint pos;

在ViewController.m文件中，将pos.x替换为pos-＆gt; x和pos.y而不是pos-＆gt; y。

Answer 3

如果在var名称和尝试实例化对象的Class之间看到*，则表示它是该对象的指针。当*不存在时，它不是指针而是硬值。

你混淆了这些东西，忘了从.h文件中的CGPoint属性中删除*。解决了这个问题，错误消失了。

CGPoint * pos ---＆gt; CGPoint pos

CGPointMake！编码错误消息

3 个答案: