iOS-仿小圆点效果

背景：

我不知道大伙们有没有遇到要做一个类似于小圆点的控件的需求，我在CocoaChina论坛上看别人说，这样的东西是会被拒审的，因为和系统的小圆点效果一样了。
管他呢，反正公司既然要求我做，那我做就是咯。

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开发思路：

目前，我学习了两种方法。

一种较为简单，自定义一个UIImageView来实现。把UIImageView的交互打开，并且实现一个拖拽的手势，拖拽手势的方法里面实现对应效果即可。

另一种，稍微复杂一点点，直接用一个UIButton来实现就好。和上面一样，也是实现一个拖拽的手势，只是拖拽手势里面算法复杂点。

两种都有各自不同的特点，看大家喜欢哪种，我比较喜欢第二种，因为第二种逼格更高点。

除了上述两种方法，还有一种方法：就是直接把控件添加到window里面去。你会发现，上述两种方法，不过都是加在根控制器的view里面去的。试想，如果当前是UIViewController还好说，如果是NavigationController呢？如果是TabBarController呢？如果是NavigationController或者是TabBarController的话，那么这个控件就会被遮挡的。怎么办？加在window上就好啦。

不过，如果项目中没有太大的硬性需求，最好不要加载window上，怪怪的。

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方法一：

////  ViewController.m//  SuspendDemo////  Created by HZhenF on 2017/9/12.//  Copyright © 2017年 HZhenF. All rights reserved.//#import "ViewController.h"#import "SuspendImgV.h"#import "OneViewController.h"#define kScreenWidth    [[UIScreen mainScreen] bounds].size.width#define kScreenHeight   [[UIScreen mainScreen] bounds].size.height@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    SuspendImgV * v = [[SuspendImgV alloc] initWithFrame:CGRectMake(100, 100, kItemWidth, kItemHeight) topMargin:66 btomMargin:44];    v.backgroundColor = [UIColor redColor];    v.image = [UIImage imageNamed:@"lufei.jpg"];    [self.view addSubview:v];    UIView  * topV = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kScreenWidth, 66)];    topV.backgroundColor = [UIColor yellowColor];    UIView  * centerV = [[UIView alloc] initWithFrame:CGRectMake(0, 66, kScreenWidth, kScreenHeight - 110)];    centerV.backgroundColor = [UIColor lightGrayColor];    UIView  * btomV = [[UIView alloc] initWithFrame:CGRectMake(0, kScreenHeight - 44, kScreenWidth, 44)];    btomV.backgroundColor = [UIColor orangeColor];    [self.view addSubview:topV];    [self.view addSubview:centerV];    [self.view addSubview:btomV];    UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 300, 100, 100)];    [btn setTitle:@"点我" forState:UIControlStateNormal];    [btn addTarget:self action:@selector(btnAction) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn];    //将悬浮视图扔到最顶层    [self.view bringSubviewToFront:v];}-(void)btnAction{    OneViewController *oneVC = [[OneViewController alloc] init];    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:oneVC];    [self presentViewController:nav animated:YES completion:nil];}@end

////  SuspendImgV.h//  SuspendDemo////  Created by HZhenF on 2017/9/12.//  Copyright © 2017年 HZhenF. All rights reserved.//#import <UIKit/UIKit.h>#define kItemWidth 60#define kItemHeight 60@interface SuspendImgV : UIImageView- (instancetype)initWithFrame:(CGRect)frame                    topMargin:(CGFloat)top                   btomMargin:(CGFloat)btom;@end

////  SuspendImgV.m//  SuspendDemo////  Created by HZhenF on 2017/9/12.//  Copyright © 2017年 HZhenF. All rights reserved.//#import "SuspendImgV.h"typedef NS_ENUM(NSInteger, Position) {    PositionLeft = 0,    PositionRight = 1,};#define kHeight self.superview.frame.size.height#define kWidth  self.superview.frame.size.width@interface SuspendImgV ()@property (nonatomic, assign) Position  position;@property (nonatomic, assign) CGFloat   topMargin;@property (nonatomic, assign) CGFloat   btomMargin;@end@implementation SuspendImgV- (instancetype)initWithFrame:(CGRect)frame topMargin:(CGFloat)top btomMargin:(CGFloat)btom;{    if (self = [super init]) {        self.frame = frame;        self.userInteractionEnabled = YES;        _topMargin = top;        _btomMargin = btom;        [self addGesture];    }    return self;}- (void)addGesture{    UIPanGestureRecognizer  * pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)];    [self addGestureRecognizer:pan];}- (void)configFrameWithAnimation:(BOOL)aniamtion{    CGPoint p = self.frame.origin;    CGRect  aimR = CGRectZero;    if (self.center.x < kWidth/2) {        aimR = CGRectMake(2, p.y, kItemWidth, kItemHeight);        _position = PositionLeft;    }else{        aimR = CGRectMake(kWidth - kItemWidth - 2, p.y, kItemWidth, kItemHeight);        _position = PositionRight;    }    if (aniamtion) {        [UIView animateWithDuration:0.2 delay:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{            self.frame = aimR;        } completion:nil];    }else{        self.frame = aimR;    }}- (void)panAction:(UIPanGestureRecognizer *)pan{    if (pan.state == UIGestureRecognizerStateEnded             || pan.state == UIGestureRecognizerStateCancelled){        //结束        [self configFrameWithAnimation:YES];    }    else {        //移动        //当然也可以相对于key window，只是self.superView的宽高和window不一致时，需要注意计算时的偏移量        CGPoint p = [pan locationInView:self.superview];        p.y = MAX(p.y, _topMargin + kItemHeight/2);        p.y = MIN(kHeight - _btomMargin - kItemHeight/2, p.y);        [UIView animateWithDuration:0.15 animations:^{            self.center = p;        }];    }}@end

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方法二：

////  ViewController.m//  SmallPoint////  Created by HZhenF on 2017/9/18.//  Copyright © 2017年 GZHYTechnology. All rights reserved.//#import "ViewController.h"// 屏幕高度#define susScreenH [UIScreen mainScreen].bounds.size.height// 屏幕宽度#define susScreenW [UIScreen mainScreen].bounds.size.width//悬浮按钮宽高#define kSuspendBtnWidth 100 * susScreenW / 375@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    CGFloat X = 0;    CGFloat Y = 100;    CGFloat W = 100;    CGFloat H = 100;    UIButton *btnOne = [[UIButton alloc] initWithFrame:CGRectMake(X, Y, W, H)];    [btnOne setImage:[UIImage imageNamed:@"girl"] forState:UIControlStateNormal];    [self.view addSubview:btnOne];    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)];    [btnOne addGestureRecognizer:panGesture];}/** 拖拽事件 @param recognizer 当前拖拽的手势 */-(void)panAction:(UIPanGestureRecognizer *)recognizer{    //移动状态    UIGestureRecognizerState recState =  recognizer.state;    switch (recState) {        case UIGestureRecognizerStateBegan:            break;        case UIGestureRecognizerStateChanged:        {            UIViewController *viewVC = self;            CGPoint translation = [recognizer translationInView:viewVC.navigationController.view];            recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);        }            break;        case UIGestureRecognizerStateEnded:        {            CGPoint stopPoint = CGPointMake(0, susScreenH / 2.0);            if (recognizer.view.center.x < susScreenW / 2.0)            {                if (recognizer.view.center.y <= susScreenH/2.0) {                    //左上                    if (recognizer.view.center.x  >= recognizer.view.center.y) {                        stopPoint = CGPointMake(recognizer.view.center.x, kSuspendBtnWidth/2.0);                    }else{                        stopPoint = CGPointMake(kSuspendBtnWidth/2.0, recognizer.view.center.y);                    }                }                else{                    //左下                    if (recognizer.view.center.x  >= susScreenH - recognizer.view.center.y) {                        stopPoint = CGPointMake(recognizer.view.center.x, susScreenH - kSuspendBtnWidth/2.0);                    }else{                        stopPoint = CGPointMake(kSuspendBtnWidth/2.0, recognizer.view.center.y);                    }                }            }            else{                if (recognizer.view.center.y <= susScreenH/2.0) {                    //右上                    if (susScreenW - recognizer.view.center.x  >= recognizer.view.center.y) {                        stopPoint = CGPointMake(recognizer.view.center.x, kSuspendBtnWidth/2.0);                    }else{                        stopPoint = CGPointMake(susScreenW - kSuspendBtnWidth/2.0, recognizer.view.center.y);                    }                }else{                    //右下                    if (susScreenW - recognizer.view.center.x  >= susScreenH - recognizer.view.center.y) {                        stopPoint = CGPointMake(recognizer.view.center.x, susScreenH - kSuspendBtnWidth/2.0);                    }else{                        stopPoint = CGPointMake(susScreenW - kSuspendBtnWidth/2.0,recognizer.view.center.y);                    }                }            }            if (stopPoint.x - kSuspendBtnWidth/2.0 <= 0) {                stopPoint = CGPointMake(kSuspendBtnWidth/2.0, stopPoint.y);            }            if (stopPoint.x + kSuspendBtnWidth/2.0 >= susScreenW) {                stopPoint = CGPointMake(susScreenW - kSuspendBtnWidth/2.0, stopPoint.y);            }            if (stopPoint.y - kSuspendBtnWidth/2.0 <= 0) {                stopPoint = CGPointMake(stopPoint.x, kSuspendBtnWidth/2.0);            }            if (stopPoint.y + kSuspendBtnWidth/2.0 >= susScreenH) {                stopPoint = CGPointMake(stopPoint.x, susScreenH - kSuspendBtnWidth/2.0);            }            [UIView animateWithDuration:0.5 animations:^{                recognizer.view.center = stopPoint;            }];        }            break;        default:            break;    }    [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];}@end