- 看扩展名是不是.gif image 有个属性:pathExtension 就可以判断
self.gifView.hidden = ![model.image1.pathExtension.lowercaseString isEqualToString:@"gif"];
- 圆形进度条的使用
使用了第三方框架DACircularProgress ,具体用法如下:
[self.pictureView sd_setImageWithPreviousCachedImageWithURL:[NSURL URLWithString:_model.image0] andPlaceholderImage:nil options:0 progress:^(NSInteger receivedSize, NSInteger expectedSize) {
self.progreessView.hidden = NO;
self.progreessView.progressLabel.text = [NSString stringWithFormat:@"%d%%",(int)(1.0 * receivedSize/expectedSize * 100)];
[self.progreessView setProgress:1.0 * receivedSize/expectedSize animated:YES];
} completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
self.progreessView.hidden = YES;
}];
-> 个人觉得这个框架还是挺好的,虽然里面有点小的bug,但是使用起来很方便,至于bug自己调调就好。
3.如果要在一个非控制器(例如UIView) 中,present出一个控制器,可以使用窗口的根控制器去present。
[[UIApplication sharedApplication].keyWindow.rootViewController presentViewController:showPicture animated:YES completion:nil];
4.为了减轻第三方框架的风险,最好的做法就是自定义,然后继承自该第三方框架。
5.图片是没办法直接添加点击事件的,需要用到手势去添加,首先打开用户交互,然后添加点击事件:
//打开图片的用户交互
self.pictureView.userInteractionEnabled = YES;
//添加图片的点击事件
[self.pictureView addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(showPicture)]];
[super awakeFromNib];
5.保存图片
- (IBAction)save {
UIImageWriteToSavedPhotosAlbum(self.imgView.image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo{
}
- 该方法必须含有这三个参数,可以点上面那个方法进去就会提醒示例方法。
-
需要配置plist文件,
否则就会报错:This app has crashed because it attempted to access privacy-sensitive data without a usage description. The app's Info.plist must contain an NSPhotoLibraryUsageDescription key with a string value explaining to the user how the app uses this data.
6.单例模式: 重写系统的方法-alloc方法,具体操作如下:
//0.提供全局变量
static MKTool * _instance;
+ (instancetype)allocWithZone:(struct _NSZone *)zone{
//加互斥锁解决多线程访问安全
// if (_instance) {
// _instance = [super allocWithZone:zone];
// }
//本身就是线程安全的
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
_instance = [super allocWithZone:zone];
});
return _instance;
}
具体可以参考这篇:ios单例模式
7.pop和Core Animation 的区别:
- Core Animation的动画只能添加到layer上
- pop的动画能添加到任何对象
- pop的底层并非基于Core Animation ,是基于CADisplaylink
- Core Animation的动画仅仅是表象,并不会真正修改对象的frame\size等值
- pop的动画修改对象的属性,真正修改可对象的属性
8.block用copy;block是属性或者参数的写法不一样:
- 属性 :
@property (nonatomic,copy) void(^myBlock)();
- 参数:
-(void)cancelWithCompletionBlock:(void(^)())myBlock;
9.窗口级别:(窗口是不用addsubview的方式添加到父控件上的,只需要控制窗口是否隐藏就好了,----------------window_.hidden = NO;)
const UIWindowLevel UIWindowLevelNormal;>
const UIWindowLevel UIWindowLevelStatusBar;>
const UIWindowLevel UIWindowLevelAlert;
10.菊花的显示:
UIActivityIndicatorView * load = [[UIActivityIndicatorView alloc]init];
load.center = CGPointMake(120, 10);
load.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhite;
[load startAnimating];
11.UIDynamic :可以认为是一种物理引擎,能模拟和仿真现实生活中的物理现象。重力、弹性碰撞等现象。
使用步骤:
1.创建物理仿真器
2.创建相应的物理仿真行为(顺便添加仿真元素)
3.将物理仿真行为添加到物理仿真器中--开始仿真注意:
1.不是任何对象都能做物理仿真元素
2.不是任何对象都能进行物理仿真那些对象才能做物理仿真元素
1.任何遵守了UIDynamicItem协议的元素
2.UIView默认遵守了UIDynamicItem协议,因此任何UI控件都能做物理仿真
实例如下:
@property (nonatomic,strong) UIDynamicAnimator * animator;
- (UIDynamicAnimator *)animator{
if (!_animator) {
_animator = [[UIDynamicAnimator alloc]initWithReferenceView:self.view];
}
return _animator;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
//1.创建物理仿真器(ReferenceView,参照视图,其实就是设置仿真范围)
//2.创建物理仿真行为 - 重力行为
UIGravityBehavior * gravity = [[UIGravityBehavior alloc]init];
gravity.gravityDirection = CGVectorMake(1, 1);
gravity.magnitude = 10;
[gravity addItem:self.blueView];
//3.添加物理仿真行为 到 物理仿真器中
[self.animator addBehavior:gravity];
}
- 比较好玩的吸附行为:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
// 获得触摸点
UITouch * touch = [touches anyObject];
CGPoint point = [touch locationInView:self.view];
//创建吸附行为
UISnapBehavior * snap = [[UISnapBehavior alloc]initWithItem:self.blueView snapToPoint:point];
//防抖系数
snap.damping = 1.0;
//添加行为
[self.animator removeAllBehaviors];
[self.animator addBehavior:snap];
}