iOS小结

• 1、相应点击指定view区域

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    NSSet *allTouches = [event allTouches];    //返回与当前接收者有关的所有的触摸对象
    UITouch *touch = [allTouches anyObject];   //视图中的所有对象
    CGPoint point = [touch locationInView:self.view]; //返回触摸点在视图中的当前坐标
    int x = point.x;
    int y = point.y;
    NSLog(@"touch (x, y) is (%d, %d)", x, y);
}

• 2、修改UITextField的默认颜色文字大小

修改默认颜色
    self.textField.placeholder = placeholder;
    [self.textField setValue:[UIColor colorwithHexString:@"cccccc"] forKeyPath:@"_placeholderLabel.textColor"];
    [self.textField setValue:[UIFont boldSystemFontOfSize:14] forKeyPath:@"_placeholderLabel.font"];

• 3、去掉字符串的空格

 NSString *str = @" sdsdijls  ijdlsj sdffsd;kl  fs;dkf;s";
    
 //去掉开头和结尾的空格
 NSString *str1 = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    
 //替换的方法 。去掉所有空格
 NSString *str2 = [str stringByReplacingOccurrencesOfString:@" " withString:@""];
    
 str1 = @"sdsdijls  ijdlsj sdffsd;kl  fs;dkf;s";
 str2 = @"sdsdijlsijdlsjsdffsd;klfs;dkf;s";

• 4、修改UITextField文字贴在边框的

// 默认情况下,当向textField输入文字时,文字会紧贴在textField左边框上.我们可以通过设置textField的leftView,设置一个只有宽度的leftView.这样还不够,因为默认leftView是不显示的.还需要将leftViewMode设置为UITextFieldViewModeAlways.这样就完成了.


    //设置文本框左边的view
    UITextField *textField = [[UITextField alloc]init];
    textField.frame = CGRectMake(10, 30, 300, 30);
    [self.view addSubview:textField];
    textField.leftView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 8, 0)];
    //设置显示模式为永远显示(默认不显示)
    textField.leftViewMode = UITextFieldViewModeAlways;

• 5、取数组中n个元素

取数组中n个元素

NSArray *array = @[@"品牌",@"颜色",@"上牌时间",@"行驶里程",@"描述"];
NSArray * array1 = [array objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(1, 3)]];
NSLog(@"array1==%@",array1);

• 6、在UITableView上添加tap手势可用的方法:

  UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapCounts)];
  tap.cancelsTouchesInView = false;
  [tableView addGestureRecognizer:tap];

• 7、UITableviewCell上的控件在点击cell时候背景颜色消失的解决方案：

lable.layer.backgroundColor=[UIColor redColor].CGColor;

• 8、打包上传app时候报错和对应的解决方法

1、ERROR ITMS-90049: “This bundle is invalid. The bundle identifier contains disallowed characters. [See the section of the Application Programming Guide entitled The Application Bundle.]” 
解决方案：找到第三方库中得info.plist文件添加bundle id ，修改bundle version ，bundle version string 
具体解决步骤：在xcode左下角搜索框搜索info.plist，搜索出所有info.plist文件对这三个key缺少的添加，不对的修改 
2、 
ERROR ITMS-90530: “Invalid MinimumOSVersion. Apps that only support 64-bit devices must specify a deployment target of 8.0 or later. MinimumOSVersion in ‘dqcclient.app’ is ‘7.0’.” 
解决方案：编译时拔掉真机，否者编译会针对真机的系统架构进行编译 
3、 
ERROR ITMS-90535: “Unexpected CFBundleExecutable Key. The bundle at ‘dqcclient.app/TencentOpenApi_IOS_Bundle.bundle’ does not contain a bundle executable. If this bundle intentionally does not contain an executable, consider removing the CFBundleExecutable key from its Info.plist and using a CFBundlePackageType of BNDL. If this bundle is part of a third-party framework, consider contacting the developer of the framework for an update to address this issue.” 
解决方案：在xcode左下角搜索框搜索info.plist，搜索出所有info.plist文件，删除掉第三方info.plist文件中的Executable file 字段 
4、 
ERROR ITMS-90529: “Invalid package. Applications built with sdk 9.0 or later must be packaged as proper IPA files.” 
解决方案：现在上传需是IPA文件 
具体解决步骤：将xcode编译的.app文件放入Payload文件夹内，压缩成.zip文件，修改其后缀为.ipa文件，即可。 

• 9、UITableViewCell 上的imageView 用SDWebimage 加载图片时候 出现内存暴涨的现象：

1.同时加载图片过多；
2.加载的图片过大；

• 10、添加延时方法 和取消延时的方法

[self performSelector:@selector(hidden) withObject:self afterDelay:3];

 [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(hidden) object:nil];//取消对应的方法
    
 [NSObject cancelPreviousPerformRequestsWithTarget:self];//取消全部。
 [[self class] cancelPreviousPerformRequestsWithTarget:self];//取消全部。

• 11、判断数组中存在某个元素

NSArray *array = @[@"品牌",@"颜色",@"上牌时间",@"行驶里程",@"描述"];
//判断数组中存在某个元素
if ([array indexOfObject:@"品牌"]!= NSNotFound) {
        NSLog(@"存在");
    }

• 12、xib上拖ScrollView 添加约束后再加label、button等导致scrollView无法滑动

-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    self.scrollView.frame = CGRectMake(0, 0, kScreenWidth, kScreenHeight);
    [self.scrollView setContentSize:CGSizeMake(kScreenWidth, 1000)];
}

• 13、数学公式

NSLog(@"%i",abs(-3));
    
    NSLog(@"%d",abs(-4));
    
    //floor() 向下取整
    NSLog(@"%f",floorf(-3.1415926));
    NSLog(@"%d",(int)floorf(-3.1415926));
    
    // ceil()向上取整
    NSLog(@"%f",ceilf(3.14));
    NSLog(@"%d",(int)ceilf(3.14));
    
    //round() 四舍五入
    NSLog(@"round()%f",roundf(3.14));
    NSLog(@"round()%d",(int)roundf(3.14));
    NSLog(@"round()%f",roundf(3.74));
    
    //fmax()求两个数的最大值
    NSLog(@"fmax()%f",fmaxf(3.14, 2.71));
    NSLog(@"fmax()%d",(int)fmaxf(3.14, 2.71));
    
    //-------------------  可以嵌套
    NSLog(@"fmax()%f",fmaxf(20.69, fmaxf(3.14, 19.87)));
    
    //fmin()求两个数的最小值
    NSLog(@"fmin%f",fmin(14, 12));
    NSLog(@"fminf()%d",(int)fminf(3.14, 3.141));
    
    //fmod()求两个数整除后的余数
    NSLog(@"fmodf%f",fmodf(5.00, 3.00));
    
    //modf()/modff()/modfl() 浮点数分解为整数和小数
    float a;
    float c;
    float b = 8.22;
    a = modff(b, &c);
    NSLog(@"modf()-整数部分-%f",c);
    NSLog(@"modf()-小数部分-%f",a);

打印结果:

打印结果：
2015-08-13 14:09:55.520 Micro Shop[15342:164204] 3
2015-08-13 14:09:55.564 Micro Shop[15342:164204] 4
2015-08-13 14:09:55.565 Micro Shop[15342:164204] -4.000000
2015-08-13 14:09:55.565 Micro Shop[15342:164204] -4
2015-08-13 14:09:55.565 Micro Shop[15342:164204] 4.000000
2015-08-13 14:09:55.565 Micro Shop[15342:164204] 4
2015-08-13 14:09:55.565 Micro Shop[15342:164204] round()3.000000
2015-08-13 14:09:55.565 Micro Shop[15342:164204] round()3
2015-08-13 14:09:55.565 Micro Shop[15342:164204] round()4.000000
2015-08-13 14:09:55.566 Micro Shop[15342:164204] fmax()3.140000
2015-08-13 14:09:55.566 Micro Shop[15342:164204] fmax()3
2015-08-13 14:09:55.566 Micro Shop[15342:164204] fmax()20.690001
2015-08-13 14:09:55.566 Micro Shop[15342:164204] fmin12.000000
2015-08-13 14:09:55.566 Micro Shop[15342:164204] fminf()3
2015-08-13 14:09:55.566 Micro Shop[15342:164204] fmodf2.000000
2015-08-13 14:09:55.566 Micro Shop[15342:164204] modf()-整数部分-8.000000
2015-08-13 14:09:55.567 Micro Shop[15342:164204] modf()-小数部分-0.220000

• 14、label增加留白（重写 - (CGSize)intrinsicContentSize）

- (CGSize)intrinsicContentSize {
CGSize originalSize = [super intrinsicContentSize];CGSize size = CGSizeMake(originalSize.width+20, originalSiz
e.height+20);return size;
}

如果是用代码约束，如果你只想设置坐标不想设置大小，那么你需要像上面的代码一样，在- (CGSize)intrinsicContentSize为你的label指定一个默认大小
如果是在Xib里，那么你需要在下面这个Instrinsic Size的属性里设置为placeholder，这样，Xcode就不会报错了