原文连接
比较实用的代码片段
比较两个CGRect/CGSize/CGPoint是否相等
CGRectEqualToRect(rect1, rect2) // 两个区域相等
CGPointEqualToPoint(point1, point2) // 两个点相等
CGSizeEqualToSize(size1, size2)) // 两个size相等
CGRectIntersectsRect(rect1, rect2) //判断两个rect是否有交叉
比较两个NSDate相差多少小时
NSDate* date1 = someDate;
NSDate* date2 = someOtherDate;
NSTimeInterval distanceBetweenDates = [date1 timeIntervalSinceDate:date2];
double secondsInAnHour = 3600;
// 除以3600是把秒化成小时，除以60得到结果为相差的分钟数
NSInteger hoursBetweenDates = distanceBetweenDates / secondsInAnHour;
每个cell之间增加间距
// 方法一，每个分区只显示一行cell，分区头当作你想要的间距(注意，从数据源数组中取值的时候需要用indexPath.section而不是indexPath.row)
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return yourArry.count;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 1;
}
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
return cellSpacingHeight;
}
// 方法二，在cell的contentView上加个稍微低一点的view，cell上原本的内容放在你的view上，而不是contentView上，这样能伪造出一个间距来。
// 方法三，自定义cell，重写setFrame：方法
- (void)setFrame:(CGRect)frame {
frame.size.height -= 20;
[super setFrame:frame];
}
判断一个字符串是否为数字
NSCharacterSet *notDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
if ([str rangeOfCharacterFromSet:notDigits].location == NSNotFound) { // 是数字
} else { // 不是数字
}
让一个view在父视图中心
child.center = [parent convertPoint:parent.center fromView:parent.superview];
获取当前导航控制器下前一个控制器
- (UIViewController *)backViewController {
NSInteger myIndex = [self.navigationController.viewControllers indexOfObject:self];
if ( myIndex != 0 && myIndex != NSNotFound ) {
return [self.navigationController.viewControllers objectAtIndex:myIndex-1];
} else {
return nil;
}
}
键盘上方增加工具栏
UIToolbar *keyboardDoneButtonView = [[UIToolbar alloc] init];
[keyboardDoneButtonView sizeToFit];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done"
style:UIBarButtonItemStyleBordered target:self
action:@selector(doneClicked:)];
[keyboardDoneButtonView setItems:[NSArray arrayWithObjects:doneButton, nil]];
txtField.inputAccessoryView = keyboardDoneButtonView;
判断某特定的cell是否已经显示
CGRect cellRect = [tableView rectForRowAtIndexPath:indexPath];
BOOL completelyVisible = CGRectContainsRect(tableView.bounds, cellRect);
UIWebView添加单击手势不响应
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(webViewClick)];
tap.delegate = self;
[_webView addGestureRecognizer:tap];
// 因为webView本身有一个单击手势，所以再添加会造成手势冲突，从而不响应。需要绑定手势代理，并实现下边的代理方法
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return YES;
}
获取手机RAM容量
// 需要导入#import
mach_port_t host_port;
mach_msg_type_number_t host_size;
vm_size_t pagesize;
host_port = mach_host_self();
host_size = sizeof(vm_statistics_data_t) / sizeof(integer_t);
host_page_size(host_port, &pagesize);
vm_statistics_data_t vm_stat;
if (host_statistics(host_port, HOST_VM_INFO, (host_info_t)&vm_stat, &host_size) != KERN_SUCCESS) {
NSLog(@"Failed to fetch vm statistics");
}
/* Stats in bytes */
natural_t mem_used = (vm_stat.active_count +
vm_stat.inactive_count +
vm_stat.wire_count) * pagesize;
natural_t mem_free = vm_stat.free_count * pagesize;
natural_t mem_total = mem_used + mem_free;
NSLog(@"已用: %u 可用: %u 总共: %u", mem_used, mem_free, mem_total);
地图上两个点之间的实际距离
// 需要导入#import
CLLocation *locA = [[CLLocation alloc] initWithLatitude:34 longitude:113];
CLLocation *locB = [[CLLocation alloc] initWithLatitude:31.05 longitude:121.76];
// CLLocationDistance求出的单位为米
CLLocationDistance distance = [locA distanceFromLocation:locB];
计算UILabel上某段文字的frame
@implementation UILabel (TextRect)
- (CGRect)boundingRectForCharacterRange:(NSRange)range
{
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:[self attributedText]];
NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
[textStorage addLayoutManager:layoutManager];
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:[self bounds].size];
textContainer.lineFragmentPadding = 0;
[layoutManager addTextContainer:textContainer];
NSRange glyphRange;
[layoutManager characterRangeForGlyphRange:range actualGlyphRange:&glyphRange];
return [layoutManager boundingRectForGlyphRange:glyphRange inTextContainer:textContainer];
}
UITextField文字周围增加边距
// 子类化UITextField，增加insert属性
@interface WZBTextField : UITextField
@property (nonatomic, assign) UIEdgeInsets insets;
@end
// 在.m文件重写下列方法
- (CGRect)textRectForBounds:(CGRect)bounds {
CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeUnlessEditing) {
return [self adjustRectWithWidthRightView:paddedRect];
}
return paddedRect;
}
- (CGRect)placeholderRectForBounds:(CGRect)bounds {
CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeUnlessEditing) {
return [self adjustRectWithWidthRightView:paddedRect];
}
return paddedRect;
}
- (CGRect)editingRectForBounds:(CGRect)bounds {
CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeWhileEditing) {
return [self adjustRectWithWidthRightView:paddedRect];
}
return paddedRect;
}
- (CGRect)adjustRectWithWidthRightView:(CGRect)bounds {
CGRect paddedRect = bounds;
paddedRect.size.width -= CGRectGetWidth(self.rightView.frame);
return paddedRect;
}
设置UITextField光标位置
// textField需要设置的textField，index要设置的光标位置
- (void)cursorLocation:(UITextField *)textField index:(NSInteger)index
{
NSRange range = NSMakeRange(index, 0);
UITextPosition *start = [textField positionFromPosition:[textField beginningOfDocument] offset:range.location];
UITextPosition *end = [textField positionFromPosition:start offset:range.length];
[textField setSelectedTextRange:[textField textRangeFromPosition:start toPosition:end]];
}
解决当UIScrollView上有UIButton的时候，触摸到button滑动不了的问题
// 子类化UIScrollView，并重写以下方法
- (instancetype)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
self.delaysContentTouches = NO;
}
return self;
}
- (BOOL)touchesShouldCancelInContentView:(UIView *)view {
if ([view isKindOfClass:UIButton.class]) {
return YES;
}
return [super touchesShouldCancelInContentView:view];
}
UITextView中的文字添加阴影效果
- (void)setTextLayer:(UITextView *)textView color:(UIColor *)color
{
CALayer *textLayer = ((CALayer *)[textView.layer.sublayers objectAtIndex:0]);
textLayer.shadowColor = color.CGColor;
textLayer.shadowOffset = CGSizeMake(0.0f, 1.0f);
textLayer.shadowOpacity = 1.0f;
textLayer.shadowRadius = 1.0f;
}
tableView实现无限滚动
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat actualPosition = scrollView.contentOffset.y;
CGFloat contentHeight = scrollView.contentSize.height - scrollView.frame.size.height;
if (actualPosition >= contentHeight) {
[self.dataArr addObjectsFromArray:self.dataArr];
[self.tableView reloadData];
}
}
代码方式调整屏幕亮度
// brightness属性值在0-1之间，0代表最小亮度，1代表最大亮度
[[UIScreen mainScreen] setBrightness:0.5];
为UIView的某个方向添加边框
// 添加UIView分类
// UIView+WZB.h
#import
/**
边框方向
- WZBBorderDirectionTop: 顶部
- WZBBorderDirectionLeft: 左边
- WZBBorderDirectionBottom: 底部
- WZBBorderDirectionRight: 右边
*/
typedef NS_ENUM(NSInteger, WZBBorderDirectionType) {
WZBBorderDirectionTop = 0,
WZBBorderDirectionLeft,
WZBBorderDirectionBottom,
WZBBorderDirectionRight
};
@interface UIView (WZB)
/**
为UIView的某个方向添加边框
@param direction 边框方向
@param color 边框颜色
@param width 边框宽度
*/
- (void)wzb_addBorder:(WZBBorderDirectionType)direction color:(UIColor *)color width:(CGFloat)width;
@end
// UIView+WZB.m
#import "UIView+WZB.h"
@implementation UIView (WZB)
- (void)wzb_addBorder:(WZBBorderDirectionType)direction color:(UIColor *)color width:(CGFloat)width
{
CALayer *border = [CALayer layer];
border.backgroundColor = color.CGColor;
switch (direction) {
case WZBBorderDirectionTop:
{
border.frame = CGRectMake(0.0f, 0.0f, self.bounds.size.width, width);
}
break;
case WZBBorderDirectionLeft:
{
border.frame = CGRectMake(0.0f, 0.0f, width, self.bounds.size.height);
}
break;
case WZBBorderDirectionBottom:
{
border.frame = CGRectMake(0.0f, self.bounds.size.height - width, self.bounds.size.width, width);
}
break;
case WZBBorderDirectionRight:
{
border.frame = CGRectMake(self.bounds.size.width - width, 0, width, self.bounds.size.height);
}
break;
default:
break;
}
[self.layer addSublayer:border];
}
通过属性设置UISwitch、UIProgressView等控件的宽高
mySwitch.transform = CGAffineTransformMakeScale(5.0f, 5.0f);
progressView.transform = CGAffineTransformMakeScale(5.0f, 5.0f);
自动搜索功能，用户连续输入的时候不搜索，用户停止输入的时候自动搜索(我这里设置的是0.5s，可根据需求更改)
// 输入框文字改变的时候调用
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
// 先取消调用搜索方法
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(searchNewResult) object:nil];
// 0.5秒后调用搜索方法
[self performSelector:@selector(searchNewResult) withObject:nil afterDelay:0.5];
}
修改UISearchBar的占位文字颜色
UITextField *searchField = [searchBar valueForKey:@"_searchField"];
[searchField setValue:[UIColor blueColor] forKeyPath:@"_placeholderLabel.textColor"];
上传图片太大，压缩图片
-(UIImage *)resizeImage:(UIImage *)image {
float actualHeight = image.size.height;
float actualWidth = image.size.width;
float maxHeight = 300.0;
float maxWidth = 400.0;
float imgRatio = actualWidth/actualHeight;
float maxRatio = maxWidth/maxHeight;
float compressionQuality = 0.5;//50 percent compression
if (actualHeight > maxHeight || actualWidth > maxWidth)
{
if(imgRatio < maxRatio)
{
//adjust width according to maxHeight
imgRatio = maxHeight / actualHeight;
actualWidth = imgRatio * actualWidth;
actualHeight = maxHeight;
}
else if(imgRatio > maxRatio)
{
//adjust height according to maxWidth
imgRatio = maxWidth / actualWidth;
actualHeight = imgRatio * actualHeight;
actualWidth = maxWidth;
}
else
{
actualHeight = maxHeight;
actualWidth = maxWidth;
}
}
CGRect rect = CGRectMake(0.0, 0.0, actualWidth, actualHeight);
UIGraphicsBeginImageContext(rect.size);
[image drawInRect:rect];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
NSData *imageData = UIImageJPEGRepresentation(img, compressionQuality);
UIGraphicsEndImageContext();
return [UIImage imageWithData:imageData];
}