1. Change the background of the cell.
UIView *cellView = [[UIView alloc] init];cellView.frame = CGRectMake(0, 0, 320, 44);cellView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"xxx.png"]];cell.selectedBackgroundView = cellView;
2. capture screen images
UIGraphicsBeginImageContext(CGSizeMake(xxx,xxx));[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];UIImage *aImage = UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();imageData = UIImagePNGRepresentation(aImage);
3. custom string color, copy code, and can be used directly
+ (Uicolor *) colorwithhexstring: (nsstring *) stringtoconvert {nsstring * cstring = [[stringtoconvert character: [nscharacterset whitespaceandnewlinecharacterset] uppercasestring]; // remove the leading and trailing space line breaks // string shocould be 6 or 8 characters if ([cstring length] <6) return [uicolor redcolor]; // strip 0x if it appears if ([cstring hasprefix: @ "0x"]) cstring = [cstring substringfromindex: 2]; If ([cstring hasprefix: @ "#"]) cstring = [cstring substringfromindex: 1]; If ([cstring length]! = 6) return [uicolor redcolor]; // separate into R, G, B substrings nsange range; range. location = 0; range. length = 2; nsstring * rstring = [cstring substringwithrange: range]; range. location = 2; nsstring * gstring = [cstring substringwithrange: range]; range. location = 4; nsstring * bstring = [cstring substringwithrange: range]; // scan values unsigned int R, G, B; [[ns1_scannerwithstring: rstring] scanhexint: & R]; // scan the hexadecimal value to int [[ns1_scannerwithstring: gstring] scanhexint: & G]; [ns1_scannerwithstring: bstring] scanhexint: & B]; return [uicolor colorwithred :( (float) r/255.0f) Green :( (float) g/255.0f) Blue :( (float) B/255.0f) ALPHA: 1.0f];}
4. compress the image, the required parameters, the image to be processed, and the size of the new image.
-(Uiimage *) imagewithimagesimple :( uiimage *) image scaledtosize :( cgsize) newsize
{
Uigraphicsbeginimagecontext (newsize );
[Image drawinrect: cgrectmake (0, 0, newsize. Width, newsize. Height)];
Uiimage * newimage =
Uigraphicsgetimagefromcurrentimagecontext ();
Uigraphicsendimagecontext ();
Return newimage;
}
5. Obtain the Label Size Based on the label content, Font, font size, and width. It is generally used to calculate the label height.
+(CGSize)getSizeForLabel:(NSString *)str fontFamily:(NSString *)fontFamily fontSize:(CGFloat)fontSize width:(NSInteger)labelWidth{ UIFont *font = [UIFontfontWithName:fontFamily size:fontSize]; CGSize size = CGSizeMake(labelWidth,3000); return [strsizeWithFont:font constrainedToSize:sizelineBreakMode:UILineBreakModeCharacterWrap];}
6. convert data into 64-bit binary data, which is generally used for image uploading.
+(NSString*) base64Encode:(NSData *)data{ static char base64EncodingTable[64] = { 'A', 'B','C', 'D', 'E','F', 'G', 'H','I', 'J', 'K','L', 'M', 'N','O', 'P', 'Q', 'R','S', 'T', 'U','V', 'W', 'X','Y', 'Z', 'a','b', 'c', 'd','e', 'f', 'g', 'h','i', 'j', 'k','l', 'm', 'n','o', 'p', 'q','r', 's', 't','u', 'v', 'w', 'x','y', 'z', '0','1', '2', '3','4', '5', '6','7', '8', '9','+', '/' }; int length = [data length]; unsigned long ixtext, lentext; long ctremaining; unsigned char input[3], output[4]; short i, charsonline = 0, ctcopy; const unsignedchar *raw; NSMutableString *result; lentext = [data length]; if (lentext < 1) return @""; result = [NSMutableStringstringWithCapacity: lentext]; raw = [data bytes]; ixtext = 0; while (true) { ctremaining = lentext - ixtext; if (ctremaining <= 0) break; for (i = 0; i <3; i++) { unsigned long ix = ixtext + i; if (ix < lentext) input[i] = raw[ix]; else input[i] = 0; } output[0] = (input[0] &0xFC) >> 2; output[1] = ((input[0] &0x03) << 4) | ((input[1] &0xF0) >> 4); output[2] = ((input[1] &0x0F) << 2) | ((input[2] &0xC0) >> 6); output[3] = input[2] &0x3F; ctcopy = 4; switch (ctremaining) { case 1: ctcopy = 2; break; case 2: ctcopy = 3; break; } for (i = 0; i < ctcopy; i++) [result appendString: [NSStringstringWithFormat: @"%c", base64EncodingTable[output[i]]]]; for (i = ctcopy; i < 4; i++) [result appendString: @"="]; ixtext += 3; charsonline += 4; if ((length > 0) && (charsonline >= length)) charsonline = 0; } return result;}