iOS实现全局悬浮按钮

本文实例为大家分享了iOS实现全局悬浮按钮的具体代码，供大家参考，具体内容如下

现在有很多app都做这个全局按钮

如上面两张图的效果，完成一个全局悬浮的按钮，而且不会划出屏幕外
既然是全局，那写在AppDelegate中
UIWindow是一种特殊的UIView，它相当于一块画框，而UIView相当于里面的画布。通常在一个app中只会有一个UIWindow。

AppDelegate.h

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) UIButton *button;

@end

AppDelegate.m

先button懒加载

- (UIButton*)button {
    if (!_button) {
        _button = [UIButton buttonWithType:UIButtonTypeCustom];
        _button.frame = CGRectMake(258, 450, 60, 60);//初始在屏幕上的位置
        [_button setImage:[UIImage imageNamed:@"bcl_btn_whole"] forState:UIControlStateNormal];
    }
    return _button;
}

然后将其加在window上，设置手势

-(void)createButton{
    if (!_button) {
        _window = [[UIApplication sharedApplication] keyWindow];
        _window.backgroundColor = [UIColor whiteColor];
        [_window addSubview:self.button];
        UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc]initWithTarget:
                                       self action:@selector(locationChange:)];
        pan.delaysTouchesBegan = YES;
        [_button addGestureRecognizer:pan];
    }
}

这个呢是为了开机启动两秒后创建全局button

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [self performSelector:@selector(createButton) withObject:nil afterDelay:2];
}

最关键的就是设置button不要划出屏幕外
以下四个else if分别为屏幕的上下左右
设置一个标记值isOVer
如果超出屏幕范围，纠正回来

-(void)locationChange:(UIPanGestureRecognizer*)p{
    CGFloat HEIGHT=_button.frame.size.height;
    CGFloat WIDTH=_button.frame.size.width;
    BOOL isOver = NO;
    CGPoint panPoint = [p locationInView:[UIApplication sharedApplication].windows[0]];
    CGRect frame = CGRectMake(panPoint.x, panPoint.y, HEIGHT, WIDTH);
    NSLog(@"%f--panPoint.x-%f-panPoint.y-", panPoint.x, panPoint.y);
    if(p.state == UIGestureRecognizerStateChanged){
        _button.center = CGPointMake(panPoint.x, panPoint.y);
    }
    else if(p.state == UIGestureRecognizerStateEnded){
        if (panPoint.x + WIDTH > KScreenWidth) {
            frame.origin.x = KScreenWidth - WIDTH;
            isOver = YES;
        } else if (panPoint.y + HEIGHT > KScreenHeight) {
            frame.origin.y = KScreenHeight - HEIGHT;
            isOver = YES;
        } else if(panPoint.x - WIDTH / 2< 0) {
            frame.origin.x = 0;
            isOver = YES;
        } else if(panPoint.y - HEIGHT / 2 < 0) {
            frame.origin.y = 0;
            isOver = YES;
        }
        if (isOver) {
            [UIView animateWithDuration:0.3 animations:^{
                self.button.frame = frame;
            }];
        }

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