iOS学习笔记26—iPhone开发常识集锦

1.检查是否有这个对象或者方法

responseToSelector:@selector

2.延时异步执行

peformSelector:withObject:afterDelay

3.模拟器路径:

/[user]/Library/Application Support/iPhone Simulator/4.2/Applications/B0E3EC07-F395-408F-9B94-A5B0BAECBC2E/Documents/personal.plist 

4.自定义发送notification

  发送消息

   NSDictionary *info = [[NSDictionaryalloc]initWithObjectsAndKeys:nil,@"ret",nil];

   [[NSNotificationCenterdefaultCenter]postNotificationOnMainThreadWithName:@"LoginSuccessful" object:self userInfo:info];

   接受消息    

   [[NSNotificationCenterdefaultCenter]addObserver:self  selector:@selector(loginSuccessful:)   name:@"LoginSuccessful"  object:nil];

1.判断邮箱格式是否正确的代码

//利用正则表达式验证

-(BOOL)isValidateEmail:(NSString *)email

{

NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";

NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES%@",emailRegex];

return [emailTest evaluateWithObject:email];

}

2.图片压缩

用法：UIImage *yourImage= [self imageWithImageSimple:image scaledToSize:CGSizeMake(210.0, 210.0)];

//压缩图片

- (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize

{

// Create a graphics image context

UIGraphicsBeginImageContext(newSize);

// Tell the old image to draw in this newcontext, with the desired

// new size

[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

// Get the new image from the context

UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();

// End the context

UIGraphicsEndImageContext();

// Return the new image.

return newImage;

}

3.亲测可用的图片上传代码

- (IBAction)uploadButton:(id)sender {

UIImage *image = [UIImage imageNamed:@"1.jpg"]; //图片名

NSData *imageData = UIImageJPEGRepresentation(image,0.5);//压缩比例

NSLog(@"字节数:%i",[imageData length]);

// post url

NSString *urlString = @"http://192.168.1.113:8090/text/UploadServlet";

//服务器地址

// setting up the request object now

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init] ;

[request setURL:[NSURL URLWithString:urlString]];

[request setHTTPMethod:@"POST"];

//

NSString *boundary = [NSString stringWithString:@"---------------------------14737809831466499882746641449"];

NSString *contentType = [NSString stringWithFormat:@"multipart/form-data;boundary=%@",boundary];

[request addValue:contentType forHTTPHeaderField: @"Content-Type"];

//

NSMutableData *body = [NSMutableData data];

[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];

[body appendData:[[NSString stringWithString:@"Content-Disposition:form-data; name=\"userfile\"; filename=\"2.png\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]]; //上传上去的图片名字

[body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];

[body appendData:[NSData dataWithData:imageData]];

[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];

[request setHTTPBody:body];

// NSLog(@"1-body:%@",body);

NSLog(@"2-request:%@",request);

NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];

NSLog(@"3-测试输出：%@",returnString);

4.给imageView加载图片

UIImage *myImage = [UIImage imageNamed:@"1.jpg"];

[imageView setImage:myImage];

[self.view addSubview:imageView];

5.对图库的操作

选择相册：

UIImagePickerControllerSourceTypesourceType=UIImagePickerControllerSourceTypeCamera;

if (![UIImagePickerControllerisSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

sourceType=UIImagePickerControllerSourceTypePhotoLibrary;

}

UIImagePickerController * picker = [[UIImagePickerControlleralloc]init];

picker.delegate = self;

picker.allowsEditing=YES;

picker.sourceType=sourceType;

[self presentModalViewController:picker animated:YES];

选择完毕：

-(void)imagePickerController:(UIImagePickerController*)pickerdidFinishPickingMediaWithInfo:(NSDictionary *)info

{

[picker dismissModalViewControllerAnimated:YES];

UIImage * image=[info objectForKey:UIImagePickerControllerEditedImage];

[self performSelector:@selector(selectPic:) withObject:imageafterDelay:0.1];

}

-(void)selectPic:(UIImage*)image

{

NSLog(@"image%@",image);

imageView = [[UIImageView alloc] initWithImage:image];

imageView.frame = CGRectMake(0, 0, image.size.width, image.size.height);

[self.viewaddSubview:imageView];

[self performSelectorInBackground:@selector(detect:) withObject:nil];

}

detect为自己定义的方法，编辑选取照片后要实现的效果

取消选择：

-(void)imagePickerControllerDIdCancel:(UIImagePickerController*)picker

{

[picker dismissModalViewControllerAnimated:YES];

}

6.跳到下个View

nextWebView = [[WEBViewController alloc] initWithNibName:@"WEBViewController" bundle:nil];

[self presentModalViewController:nextWebView animated:YES];

//创建一个UIBarButtonItem右边按钮

UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithTitle:@"右边" style:UIBarButtonItemStyleDone target:self action:@selector(clickRightButton)];

[self.navigationItem setRightBarButtonItem:rightButton];

设置navigationBar隐藏

self.navigationController.navigationBarHidden = YES;//

iOS开发之UIlabel多行文字自动换行 （自动折行）

UIView *footerView = [[UIView alloc]initWithFrame:CGRectMake(10, 100, 300, 180)];

UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(10, 100, 300, 150)];

label.text = @"Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Helloworld!";

//背景颜色为红色

label.backgroundColor = [UIColor redColor];

//设置字体颜色为白色

label.textColor = [UIColor whiteColor];

//文字居中显示

label.textAlignment = UITextAlignmentCenter;

//自动折行设置

label.lineBreakMode = UILineBreakModeWordWrap;

label.numberOfLines = 0;

7.代码生成button

CGRect frame = CGRectMake(0, 400, 72.0, 37.0);

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];

button.frame = frame;

[button setTitle:@"新添加的按钮" forState: UIControlStateNormal];

button.backgroundColor = [UIColor clearColor];

button.tag = 2000;

[button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:button];

8.让某个控件在View的中心位置显示

（某个控件，比如label，View）label.center = self.view.center;

9.好看的文字处理

以tableView中cell的textLabel为例子：

cell.backgroundColor = [UIColorscrollViewTexturedBackgroundColor];

//设置文字的字体

cell.textLabel.font = [UIFont fontWithName:@"AmericanTypewriter" size:100.0f];

//设置文字的颜色

cell.textLabel.textColor = [UIColor orangeColor];

//设置文字的背景颜色

cell.textLabel.shadowColor = [UIColor whiteColor];

//设置文字的显示位置

cell.textLabel.textAlignment = UITextAlignmentCenter;

10.隐藏Status Bar

读者可能知道一个简易的方法,那就是在程序的viewDidLoad中加入

[[UIApplication sharedApplication]setStatusBarHidden:YES animated:NO];

11.更改AlertView背景

UIAlertView *theAlert = [[[UIAlertViewalloc] initWithTitle:@"Atention"

message: @"I'm a Chinese!"

delegate:nil

cancelButtonTitle:@"Cancel"

otherButtonTitles:@"Okay",nil] autorelease];

[theAlert show];

UIImage *theImage = [UIImageimageNamed:@"loveChina.png"];

theImage = [theImage stretchableImageWithLeftCapWidth:0topCapHeight:0];

CGSize theSize = [theAlert frame].size;

UIGraphicsBeginImageContext(theSize);

[theImage drawInRect:CGRectMake(5, 5, theSize.width-10, theSize.height-20)];//这个地方的大小要自己调整，以适应alertview的背景颜色的大小。

theImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

theAlert.layer.contents = (id)[theImage CGImage];

12.键盘透明

textField.keyboardAppearance = UIKeyboardAppearanceAlert;

状态栏的网络活动风火轮是否旋转

[UIApplication sharedApplication].networkActivityIndicatorVisible，默认值是NO。

13.截取屏幕图片

//创建一个基于位图的图形上下文并指定大小为CGSizeMake(200,400)

UIGraphicsBeginImageContext(CGSizeMake(200,400));

//renderInContext 呈现接受者及其子范围到指定的上下文

[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

//返回一个基于当前图形上下文的图片

UIImage *aImage = UIGraphicsGetImageFromCurrentImageContext();

//移除栈顶的基于当前位图的图形上下文

UIGraphicsEndImageContext();

//以png格式返回指定图片的数据

imageData = UIImagePNGRepresentation(aImage);

14.更改cell选中的背景

UIView *myview = [[UIView alloc] init];

myview.frame = CGRectMake(0, 0, 320, 47);

myview.backgroundColor = [UIColorcolorWithPatternImage:[UIImage imageNamed:@"0006.png"]];

cell.selectedBackgroundView = myview;

15.显示图像

CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0f, 109.0f);

UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect];

[myImage setImage:[UIImage imageNamed:@"myImage.png"]];

myImage.opaque = YES; //opaque是否透明

[self.view addSubview:myImage];

16.能让图片适应框的大小（没有确认）

NSString*imagePath = [[NSBundle mainBundle] pathForResource:@"XcodeCrash"ofType:@"png"];

UIImage *image = [[UIImage alloc]initWithContentsOfFile:imagePath];

UIImage *newImage= [image transformWidth:80.f height:240.f];

UIImageView *imageView = [[UIImageView alloc]initWithImage:newImage];

[newImagerelease];

[image release];

[self.view addSubview:imageView];

17.实现点击图片进行跳转的代码：生成一个带有背景图片的button，给button绑定想要的事件！

UIButton *imgButton=[[UIButton alloc]initWithFrame:CGRectMake(0, 0, 120, 120)];

[imgButton setBackgroundImage:(UIImage *)[self.imgArray objectAtIndex:indexPath.row] forState:UIControlStateNormal];

imgButton.tag=[indexPath row];

[imgButton addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];