这里记录一些收集到的小技巧。
这里有很多Demo http://www.cocoachina.com/bbs/read.php?tid-12269.html
1：改变按钮状态
[button setTitle:@"未按" forState:UIControlStateNormal];
[button setTitle:@"已按" forState:UIControlStateHighlighted];
[button setBackgroundImage:[UIImage imageNamed:@"1.png"] forState:UIControlStateNormal];
[button setBackgroundImage:[UIImage imageNamed:@"2.png"] forState:UIControlStateHighlighted];
2：自定义UINavigationBar背景图片
在网上找到的显示自定义UINavigationBar背景图片的例子代码，发现没有自己想要的，或者好用的，
于是，根据网上的例子，自己编写了下面的一段代码，希望可以给想要的人帮助。
调用很简单，就不介绍了；
在drawDraw方法中注释掉的代码，事用来自定义UINavigationBar背景色的，
如果想用，可以参考自定义图片的方法。
//
// myCustomNavigationBarImage.h
//
#import <Foundation/Foundation.h>
@interface UINavigationBar (CustomImage)
- (void) drawRect: (CGRect)rect;
- (void) setImage: (NSString *)image;
@end
//
// myCustomNavigationBarImage.m
//
#import "myCustomNavigationBarImage.h"
static UIImage *barImage = nil;
@implementation UINavigationBar (CustomImage)
- (void) drawRect: (CGRect)rect
{
if (barImage != nil)
{
[barImage drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
[barImage release];
barImage = nil;
}
else
{
// UIColor *color = [UIColor redColor];
// CGContextRef context = UIGraphicsGetCurrentContext();
// CGContextSetFillColor(context, CGColorGetComponents( [color CGColor]));
// CGContextFillRect(context, rect);
// self.tintColor = color;
}
}
- (void) setImage: (NSString *)image
{
barImage = [ UIImage imageNamed:image];
[self setNeedsDisplay];
}
@end
3:iphone/ipad设置背景图片
方法一，使用一个UIImageView实例做子视图，并且放最后面
- (void)setBackgroundImage {
NSLog(@"setting bg image");
UIImageView *customBackground = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"background.jpg"]];
self.background = customBackground;
[customBackground release];
[self addSubview:background];
NSLog(@"Added background subview %@", background);
[self sendSubviewToBack:background];
}
方法二，Cook Book中提到的方法
- (void)loadView {
UIImageView *contentView = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
[contentView setImage:[UIImage imageNamed:@"Default.png"]];
[contentView setUserInteractionEnabled:YES];
self.view = contentView;
[contentView release];
}
方法三，uiView是UIView的实例，而不是UIImageView
uiView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"Default.png"]];
4:objective-c 解析html
本段在 Objective-C 中解析 html 的代码由 CocoaChina 会员 “月华如水” 分享，希望对开发者们有所帮助
#import "StringChuLi.h"
/*
项目作用：链接网络解析html
*/
@implementation StringChuLi
//访问网页源码
-(NSString *)urlString:(NSString *)value{
NSURL *url = [NSURL URLWithString:value];
NSData *data = [NSData dataWithContentsOfURL:url];
//解决中文乱码,用GBK
NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
NSString *retStr = [[NSString alloc] initWithData:data encoding:enc];
return retStr;
}
/*
作用:截取从value1到value2之间的字符串
str:要处理的字符串
value1:左边匹配字符串
value2:右边匹配字符串
*/
-(NSString *)str:(NSString *)str value1:(NSString *)value1 value2:(NSString *)value2{
//i:左边匹配字符串在str中的下标
int i;
//j:右边匹配字符串在str1中的下标
int j;
//该类可以通过value1匹配字符串
NSRange range1 = [str rangeOfString:value1];
//判断range1是否匹配到字符串
if(range1.length>0){
//把其转换为NSString
NSString *result1 = NSStringFromRange(range1);
i = [self indexByValue:result1];
//原因:加上匹配字符串的长度从而获得正确的下标
i = i+[value1 length];
}
//通过下标，删除下标以前的字符
NSString *str1 = [str substringFromIndex:i];
NSRange range2 = [str1 rangeOfString:value2];
if(range2.length>0){
NSString *result2 = NSStringFromRange(range2);
j = [self indexByValue:result2];
}
NSString *str2 = [str1 substringToIndex:j];
return str2;
}
//过滤获得的匹配信息的下标
-(int)indexByValue:(NSString *)str{
//使用NSMutableString类，它可以实现追加
NSMutableString *value = [[NSMutableString alloc] initWithFormat:@""];
NSString *colum2 = @"";
int j = 0;
//遍历出下标值
for(int i=1;i<[str length];i++){
NSString *colum1 = [str substringFromIndex:i];
[value appendString:colum2];
colum2 = [colum1 substringToIndex:1];
if([colum2 isEqualToString:@","]){
j = [value intValue];
break;
}
}
[value release];
return j;
}
@end
读 Plist 文件
NSString *errorDesc = nil ;
NSPropertyListFormat format;
NSString *rootPath = [ NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory , NSUserDomainMask , YES ) objectAtIndex : 0 ];
NSString *plistPath = [rootPath stringByAppendingPathComponent : @"bookmarks.plist" ];
if (![[ NSFileManager defaultManager ] fileExistsAtPath :plistPath]) {
plistPath = [[ NSBundle mainBundle ] pathForResource : @"bookmarks" ofType : @"plist" ];
}
NSData *plistXML = [[ NSFileManager defaultManager ] contentsAtPath :plistPath];
context . bookmarksDic = ( NSMutableDictionary *)[[ NSPropertyListSerialization propertyListFromData :plistXML mutabilityOption : NSPropertyListMutableContainersAndLeaves
format :&format
errorDescription :&errorDesc] retain];
keysArr = [[[ context . bookmarksDic allKeys ] sortedArrayUsingSelector : @selector ( compare :)] retain ];
if (! context . bookmarksDic ) {
NSLog ( @"Error reading plist: %@, format: %d" , errorDesc, format);
}
写入 Plist
Context * context = [ Context getInstance ];
NSString *rootPath = [ NSSearchPathForDirectoriesInDomains ( NSDocumentDirectory ,
NSUserDomainMask , YES ) objectAtIndex : 0 ];
NSString *plistPath = [rootPath stringByAppendingPathComponent : @"bookmarks.plist" ];
NSString *error;
NSData *plistData = [ NSPropertyListSerialization dataFromPropertyList : context . bookmarksDic
format : NSPropertyListXMLFormat_v1_0
errorDescription :&error];
if (plistData) {
[plistData writeToFile :plistPath atomically : YES ];
}
else {
NSLog ( @"%@" ,error);
[error release ];
}
6：按钮加事件
[button addTarget:self
action:@selector(buttonClicked:)
forControlEvents:UIControlEventTouchUpInside];
7：比较系统版本
NSString *reqSysVer = @"3.1";
NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
if([currSysVer compare:reqSysVer options:NSNumericSearch] == NSOrderedAscending)
return NO;
8:国际化支持
1先在代码里用 NSLocalizedString(@"One",@"The number 1");替代你的字符串，
最后打开Finder 将LocalizeMe项目文件夹拖动到终端窗口中，
命令，genstrings ./Classes/*.m
将会生产，Localizable.strings文件
修改UIAlertView颜色
[CustomAlert setBackgroundColor:[UIColor blueColor]
withStrokeColor:[UIColor greenColor]];
CustomAlert.h
#import <UIKit/UIKit.h>
@interface CustomAlert : UIAlertView
{
}
+ (void) setBackgroundColor:(UIColor *) background
withStrokeColor:(UIColor *) stroke;
@end
CustomAlert.m
#import "CustomAlert.h"
@interface CustomAlert (Private)
- (void) drawRoundedRect:(CGRect) rect inContext:(CGContextRef)
context withRadius:(CGFloat) radius;
@end
static UIColor *fillColor = nil;
static UIColor *borderColor = nil;
@implementation CustomAlert
+ (void) setBackgroundColor:(UIColor *) background
withStrokeColor:(UIColor *) stroke
{
if(fillColor != nil)
{
[fillColor release];
[borderColor release];
}
fillColor = [background retain];
borderColor = [stroke retain];
}
- (id)initWithFrame:(CGRect)frame
{
if((self = [super initWithFrame:frame]))
{
if(fillColor == nil)
{
fillColor = [[UIColor blackColor] retain];
borderColor = [[UIColor colorWithHue:0.625
saturation:0.0 brightness:0.8 alpha:0.8]
retain];
}
}
return self;
}
- (void)layoutSubviews
{
for (UIView *sub in [self subviews])
{
if([sub class] == [UIImageView class] && sub.tag == 0)
{
// The alert background UIImageView tag is 0,
// if you are adding your own UIImageView's
// make sure your tags != 0 or this fix
// will remove your UIImageView's as well!
[sub removeFromSuperview];
break;
}
}
}
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClearRect(context, rect);
CGContextSetAllowsAntialiasing(context, true);
CGContextSetLineWidth(context, 0.0);
CGContextSetAlpha(context, 0.8);
CGContextSetLineWidth(context, 2.0);
CGContextSetStrokeColorWithColor(context, [borderColor CGColor]);
CGContextSetFillColorWithColor(context, [fillColor CGColor]);
// Draw background
CGFloat backOffset = 2;
CGRect backRect = CGRectMake(rect.origin.x + backOffset,
rect.origin.y + backOffset,
rect.size.width - backOffset*2,
rect.size.height - backOffset*2);
[self drawRoundedRect:backRect inContext:context withRadius:8];
CGContextDrawPath(context, kCGPathFillStroke);
// Clip Context
CGRect clipRect = CGRectMake(backRect.origin.x + backOffset-1,
backRect.origin.y + backOffset-1,
backRect.size.width - (backOffset-1)*2,
backRect.size.height - (backOffset-1)*2);
[self drawRoundedRect:clipRect inContext:context withRadius:8];
CGContextClip (context);
//Draw highlight
CGGradientRef glossGradient;
CGColorSpaceRef rgbColorspace;
size_t num_locations = 2;
CGFloat locations[2] = { 0.0, 1.0 };
CGFloat components[8] = { 1.0, 1.0, 1.0, 0.35, 1.0, 1.0, 1.0, 0.06 };
rgbColorspace = CGColorSpaceCreateDeviceRGB();
glossGradient = CGGradientCreateWithColorComponents(rgbColorspace,
components, locations, num_locations);
CGRect ovalRect = CGRectMake(-130, -115, (rect.size.width*2),
rect.size.width/2);
CGPoint start = CGPointMake(rect.origin.x, rect.origin.y);
CGPoint end = CGPointMake(rect.origin.x, rect.size.height/5);
CGContextSetAlpha(context, 1.0);
CGContextAddEllipseInRect(context, ovalRect);
CGContextClip (context);
CGContextDrawLinearGradient(context, glossGradient, start, end, 0);
CGGradientRelease(glossGradient);
CGColorSpaceRelease(rgbColorspace);
}
- (void) drawRoundedRect:(CGRect) rrect inContext:(CGContextRef) context
withRadius:(CGFloat) radius
{
CGContextBeginPath (context);
CGFloat minx = CGRectGetMinX(rrect), midx = CGRectGetMidX(rrect),
maxx = CGRectGetMaxX(rrect);
CGFloat miny = CGRectGetMinY(rrect), midy = CGRectGetMidY(rrect),
maxy = CGRectGetMaxY(rrect);
CGContextMoveToPoint(context, minx, midy);
CGContextAddArcToPoint(context, minx, miny, midx, miny, radius);
CGContextAddArcToPoint(context, maxx, miny, maxx, midy, radius);
CGContextAddArcToPoint(context, maxx, maxy, midx, maxy, radius);
CGContextAddArcToPoint(context, minx, maxy, minx, midy, radius);
CGContextClosePath(context);
}
- (void)dealloc
{
[super dealloc];
}
@end
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