// 是否高清屏
#define isRetina ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 960), [[UIScreen mainScreen] currentMode].size) : NO)
// 是否iPad
#define isPad (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
// 是否模拟器
#define isSimulator (NSNotFound != [[[UIDevice currentDevice] model] rangeOfString:@"Simulator"].location)
// 是否iphone5
#define IS_IPHONE_5 (fabs((double)[[UIScreen mainScreen] bounds].size.height - (double)568)<DBL_EPSILON)
//计算点到线段的最短距离
double x1, y1, x2, y2, x3, y3;
double px = x2 - x1;
double py = y2 - y1;
double som = px * px + py * py;
double u = ((x3 - x1) * px + (y3 - y1) * py) / som;
if (u > 1) {
u = 1;
}
if (u < 0) {
u = 0;
}
//the closest point
double x = x1 + u * px;
double y = y1 + u * py;
double dx = x - x3;
double dy = y - y3;
double dist = sqrt(dx*dx + dy*dy);
//怎么样判断两线段是否相交？ 知道两线段的起始坐标和终止坐标
bool IsLineSegmentCross(POINT pFirst1, POINT pFirst2, POINT pSecond1, POINT pSecond2)
{
//每个线段的两点都在另一个线段的左右不同侧，则能断定线段相交
//公式对于向量(x1,y1)->(x2,y2),判断点(x3,y3)在向量的左边,右边,还是线上.
//p=x1(y3-y2)+x2(y1-y3)+x3(y2-y1).p<0 左侧, p=0 线上, p>0 右侧
long Linep1,Linep2;
//判断pSecond1和pSecond2是否在pFirst1->pFirst2两侧
Linep1 = pFirst1.x * (pSecond1.y - pFirst2.y) +
pFirst2.x * (pFirst1.y - pSecond1.y) +
pSecond1.x * (pFirst2.y - pFirst1.y);
Linep2 = pFirst1.x * (pSecond2.y - pFirst2.y) +
pFirst2.x * (pFirst1.y - pSecond2.y) +
pSecond2.x * (pFirst2.y - pFirst1.y);
if ( ((Linep1 ^ Linep2) >= 0 ) && !(Linep1==0 && Linep2==0))//符号位异或为0:pSecond1和pSecond2在pFirst1->pFirst2同侧
{
return false;
}
//判断pFirst1和pFirst2是否在pSecond1->pSecond2两侧
Linep1 = pSecond1.x * (pFirst1.y - pSecond2.y) +
pSecond2.x * (pSecond1.y - pFirst1.y) +
pFirst1.x * (pSecond2.y - pSecond1.y);
Linep2 = pSecond1.x * (pFirst2.y - pSecond2.y) +
pSecond2.x * (pSecond1.y - pFirst2.y) +
pFirst2.x * (pSecond2.y - pSecond1.y);
if ( ((Linep1 ^ Linep2) >= 0 ) && !(Linep1==0 && Linep2==0))//符号位异或为0:pFirst1和pFirst2在pSecond1->pSecond2同侧
{
return false;
}
//否则判为相交
return true;
}
实现下面的委托
#define NUMBERS @"0123456789\n"
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSCharacterSet *cs;
if(textField == phoneNumberField)
{
cs = [[NSCharacterSet characterSetWithCharactersInString:NUMBERS] invertedSet];
NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
BOOL basicTest = [string isEqualToString:filtered];
if(!basicTest)
{
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"提示"
message:@"请输入数字"
delegate:nil
cancelButtonTitle:@"确定"
otherButtonTitles:nil];
[alert show];
[alert release];
return NO;
}
}
//其他的类型不需要检测，直接写入
return YES;
}
如果输入的不是数字，进行提示。
string 转成 char:
char mychar[100];
NSString * mystring;
strcpy(mychar,(char *)[mystring UTF8String]);
char 转成 string:
NSString *TempString;
char mychar[100];
mystring=[NSString stringWithFormat:@"%s",mychar];
/*
Erica Sadun, [url]http://ericasadun.com[/url]
iPhone Developer's Cookbook, 3.0 Edition
BSD License, Use at your own risk
*/
#import <foundation foundation.h="">
@interface NSString (UtilityExtensions)
- (NSString *) stringByAppendingRandomStringOfRandomLength;
- (int) occurrencesOfString: (NSString *) aString;
- (NSDate *) date;
+ (NSString *) commasForNumber: (long long) num;
@property (readonly) NSString *trimmedString;
@property (readonly) NSDate *date;
@end
@interface NSString (UTF8String)
@property (readonly) char *UTF8String; // a favorite!
@end
/*
Erica Sadun, [url]http://ericasadun.com[/url]
iPhone Developer's Cookbook, 3.0 Edition
BSD License, Use at your own risk
*/
#import "NSString-Utilities.h"
@implementation NSString (UtilityExtensions)
- (NSString *) trimmedString
{
return [self stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}
- (int) occurrencesOfString: (NSString *) aString
{
return [self componentsSeparatedByString:aString].count -1;
}
// run srandom() somewhere in your app // [url]http://tinypaste.com/5f1c9[/url]
// Requested by BleuLlama
- (NSString *) stringByAppendingRandomStringOfRandomLength
{
int len = random() % 32;
NSMutableArray *chars = [NSMutableArray array];
NSMutableString *s = [NSMutableString stringWithString:self];
NSMutableCharacterSet *cs = [[NSMutableCharacterSet alloc] init];
[cs formUnionWithCharacterSet:[NSCharacterSet alphanumericCharacterSet]];
[cs formUnionWithCharacterSet:[NSCharacterSet whitespaceCharacterSet]];
// [cs formUnionWithCharacterSet:[NSCharacterSet symbolCharacterSet]];
// [cs formUnionWithCharacterSet:[NSCharacterSet punctuationCharacterSet]];
// init char array from charset
for (int c = 0; c < 128; c++) // 7 bit only
if ([cs characterIsMember:(unichar)c])
[chars addObject:[NSString stringWithFormat:@"%c", c]];
for (int i = 0; i < len; i++) [s appendString:[chars objectAtIndex:(random() % chars.count)]];
[cs release];
return s;
}
- (NSDate *) date
{
// Return a date from a string
NSDateFormatter *formatter = [[[NSDateFormatter alloc] init] autorelease];
formatter.dateFormat = @"MM-dd-yyyy";
NSDate *date = [formatter dateFromString:self];
return date;
}
// return a comma delimited string
+ (NSString *) commasForNumber: (long long) num
{
if (num < 1000) return [NSString stringWithFormat:@"%d", num];
return [[self commasForNumber:num/1000] stringByAppendingFormat:@",%03d", (num % 1000)];
}
@end
//保存当前view到相册
UIGraphicsBeginImageContext(currentView.bounds.size); //currentView 当前的view
[currentView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
//iPhone 处理大文件(MD5)
+(NSString*)fileMD5:(NSString*)path
{
NSFileHandle *handle = [NSFileHandle fileHandleForReadingAtPath:path];
if( handle== nil ) return @"ERROR GETTING FILE MD5"; // file didnt exist
CC_MD5_CTX md5;
CC_MD5_Init(&md5);
BOOL done = NO;
while(!done)
{
NSData* fileData = [handle readDataOfLength: CHUNK_SIZE ];
CC_MD5_Update(&md5, [fileData bytes], [fileData length]);
if( [fileData length] == 0 ) done = YES;
}
unsigned char digest[CC_MD5_DIGEST_LENGTH];
CC_MD5_Final(digest, &md5);
NSString* s = [NSString stringWithFormat: @"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
digest[0], digest[1],
digest[2], digest[3],
digest[4], digest[5],
digest[6], digest[7],
digest[8], digest[9],
digest[10], digest[11],
digest[12], digest[13],
digest[14], digest[15]];
return s;
}