原文地址:http://blog.5ibc.net/p/86562.html
前提：当时看到别人写过这个类似AssistiveTouch的demo，但是有问题，第一改变不了位置、第二切换页面后无法使用、第三运行时偶尔会崩溃。然后自己就去度娘、论坛中都查了一些资料，然后结合起来写了这么一个demo。
思路：实现全局 需要在 AppDelegate.m 文件中 didFinishLaunchingWithOptions 方法里面实现 1、新建一个 继承于 UIWindow 的类 AssistiveTouch//在 AssistiveTouch.h 文件中代码
#import@interface AssistiveTouch : UIWindow{ UIButton *_button;}-(id) initWithFrame:(CGRect)frame;@end
//在 AssistiveTouch.m 文件中代码
#import "AssistiveTouch.h"@interface AssistiveTouch ()@end@implementation AssistiveTouch/*// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect { // Drawing code}*/-(id)initWithFrame:(CGRect)frame{ self = [super initWithFrame:frame]; if (self) { self.backgroundColor = [UIColor clearColor]; self.windowLevel = UIWindowLevelAlert + 1;//这句话很重要 [self makeKeyAndVisible]; _button = [UIButton buttonWithType:UIButtonTypeCustom]; _button.backgroundColor = [UIColor grayColor]; _button.frame = CGRectMake(0, 0, frame.size.width, frame.size.height); _button.layer.cornerRadius = frame.size.width/2; [_button addTarget:self action:@selector(choose) forControlEvents:UIControlEventTouchUpInside]; [self addSubview:_button];//放一个拖动手势，用来改变控件的位置 UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(changePostion:)]; [_button addGestureRecognizer:pan]; } return self;}//按钮事件-(void)choose{ NSLog(@"悬浮窗");}//手势事件 －－ 改变位置-(void)changePostion:(UIPanGestureRecognizer *)pan{ CGPoint point = [pan translationInView:self]; CGFloat width = [UIScreen mainScreen].bounds.size.width; CGFloat height = [UIScreen mainScreen].bounds.size.height; CGRect originalFrame = self.frame; if (originalFrame.origin.x >= 0 && originalFrame.origin.x+originalFrame.size.width <= width) { originalFrame.origin.x += point.x; } if (originalFrame.origin.y >= 0 && originalFrame.origin.y+originalFrame.size.height <= height) { originalFrame.origin.y += point.y; } self.frame = originalFrame; [pan setTranslation:CGPointZero inView:self]; if (pan.state == UIGestureRecognizerStateBegan) { _button.enabled = NO; }else if (pan.state == UIGestureRecognizerStateChanged){ } else { CGRect frame = self.frame; //记录是否越界 BOOL isOver = NO; if (frame.origin.x < 0) { frame.origin.x = 0; isOver = YES; } else if (frame.origin.x+frame.size.width > width) { frame.origin.x = width - frame.size.width; isOver = YES; } if (frame.origin.y < 0) { frame.origin.y = 0; isOver = YES; } else if (frame.origin.y+frame.size.height > height) { frame.origin.y = height - frame.size.height; isOver = YES; } if (isOver) { [UIView animateWithDuration:0.3 animations:^{ self.frame = frame; }]; } _button.enabled = YES; } }@end #import "AppDelegate.h"#import "AssistiveTouch.h"@interface AppDelegate (){ //悬浮框 AssistiveTouch * _Win;}@end@implementation AppDelegate// 设置自定义悬浮框坐标-(void)setNew{ _Win = [[AssistiveTouch alloc] initWithFrame:CGRectMake(0, 0, 60, 60)];}- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. // 这句话很重要，要先将rootview加载完成之后在显示悬浮框，如没有这句话，将可能造成程序崩溃 [self performSelector:@selector(setNew) withObject:nil afterDelay:3]; [self.window makeKeyAndVisible]; return YES;}