iOS开发基础知识--碎片43

 iOS开发基础知识--碎片43

1：增加手势进行左划效果，针对视图并修改其中一个的坐标，菜单用隐藏跟显示

@property(strong,nonatomic)UISwipeGestureRecognizer *recognizer;

self.recognizer = [[ UISwipeGestureRecognizer alloc ] initWithTarget:self action:@selector (handleSwipeFrom:)];
[self.recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
[self addGestureRecognizer :self.recognizer];

- (void)handleSwipeFrom:( UISwipeGestureRecognizer *)sender{if (sender.direction == UISwipeGestureRecognizerDirectionLeft )
    {
        self.rightButton.hidden=NO;
        [self.recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];

        [self.valueLabel mas_remakeConstraints:^(MASConstraintMaker *make) {
            make.right.mas_equalTo(self.rightButton.left).with.offset(-5);
            make.centerY.mas_equalTo(self).with.offset(0);
            make.size.mas_equalTo(CGSizeMake(Main_Screen_Width-180, 15));
        }];
        [self.valueLabel layoutIfNeeded];
    }
    else
    {
        self.rightButton.hidden=YES;
        [self.recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];

        [self.valueLabel mas_remakeConstraints:^(MASConstraintMaker *make) {
            make.right.mas_equalTo(self.right).with.offset(-15);
            make.centerY.mas_equalTo(self).with.offset(0);
            make.size.mas_equalTo(CGSizeMake(Main_Screen_Width-180, 15));
        }];
        [self.valueLabel layoutIfNeeded];
    }
}

2:属性名以new开头解决方式

@property (nonatomic,copy) NSString *new_Passwd;

像上面这样写法会报错，可以替换成

@property (nonatomic,copy,getter = theNewPasswd) NSString *new_Passwd;

3：单例类一些注意事项

如果allocWithZone里面的代码不写，用以下三种创建的实例还是三种，不符合我们对单例的运用，当然如果你只针对[HLTestObject sharedInstance]进行实例化时，就是一直满足；把初始化的属性对象放在sharedInstance里面，如果放在init里面进行初始化也会出现不一样的情景；

HLTestObject *objct1 = [HLTestObject sharedInstance];
NSLog(@"%@",objct1);
HLTestObject *objc2 = [[HLTestObject alloc] init];
NSLog(@"%@",objc2);
HLTestObject *objc3 = [HLTestObject new];
NSLog(@"%@",objc3);

声明属性：

@property (assign, nonatomic)   int  height;
@property (strong, nonatomic)   NSObject  *object;
@property (strong, nonatomic)   NSMutableArray  *arrayM;

代码内容：

static HLTestObject *instance = nil;
+ (instancetype)sharedInstance
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        instance = [[[self class] alloc] init];
        instance.height = 10;
        instance.object = [[NSObject alloc] init];
        instance.arrayM = [[NSMutableArray alloc] init];
    });
    return instance;
}
+ (instancetype)allocWithZone:(struct _NSZone *)zone
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        instance = [super allocWithZone:zone];
    });
    return instance;
}
- (NSString *)description
{
    NSString *result = @"";
    result = [result stringByAppendingFormat:@"<%@: %p>",[self class], self];
    result = [result stringByAppendingFormat:@" height = %d,",self.height];
    result = [result stringByAppendingFormat:@" arrayM = %p,",self.arrayM];
    result = [result stringByAppendingFormat:@" object = %p,",self.object];
    return result;
}

4:UITextField实现左侧空出一定的边距

就是通过uitextfield的leftview来实现的，同时要设置leftviewmode。

如果设置左右边距，需要再加上rightView功能

-(void)setTextFieldLeftPadding:(UITextField *)textField forWidth:(CGFloat)leftWidth
{
    CGRect frame = textField.frame;
    frame.size.width = leftWidth;
    UIView *leftview = [[UIView alloc] initWithFrame:frame];
    textField.leftViewMode = UITextFieldViewModeAlways;
    textField.leftView = leftview;
}

5:UICollectionView异步加载的实例

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString * CellIdentifier = @"Event";
    EventCollectionViewCell *cell  = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];

    Event *event = [events objectAtIndex:indexPath.item];  // replace "Event" with whatever class you use for your items实体
    cell.eventTitle.text = [event objectForKey:@"title"];
    cell.eventImage.image = [event objectForKey:@"image"];
    if (cell.eventImage.image == nil) {
        NSString *imageUrl = [[[events objectAtIndex:indexPath.item] objectForKey:@"photo"] objectForKey:@"url"];

        dispatch_queue_t imageFetchQ = dispatch_queue_create("image fetched", NULL);
        dispatch_async(imageFetchQ, ^{
            __weak UICollectionView *weakCollection;
            NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:imageUrl]];
            UIImage *image = [UIImage imageWithData:imageData];
            if (image)
            {
                dispatch_async(dispatch_get_main_queue(), ^{
                    [event setObject:image forKey:@"image"]; // updating the model here
                    [weakCollection reloadItemsAtIndexPaths:@[indexPath]];
                });
            }
        });
    }
    return cell;
}

6：如何拿到别人APP图片

a：打开你Mac上的iTunes，点击我的应用, 找到刚下载好的应用, 右击在finder中显示

b：按Enter(回车键), 修改微信ipa文件的后缀为.zip, 即把微信 6.3.22.ipa变成微信 6.3.22.zip, 此处会有一个提示, 问你是否确定修改扩展名, 点击使用.zip即可

c：直接双击zip进行解压, 打开解压好的文件夹, 进入Payload文件夹 此时, 就拿到了大多数的资源. 包括css, js, 图片, MP3/4, 字体,xib等等资源

d：取Assets.car中的资源 （工具下载地址: http://pan.baidu.com/s/1kUVAT7p 提取密码: qrt5）

e：我们在上面的E步骤所在的文件夹处搜索Assets.car即可 直接将Assets.car拖入其中即可, 对, 拖进去就行了，点击start, 完成后, 点击Output Dir即可（ iOS APP中所有资源 =  Assets.car +  .api文件解压）