ios小技巧

ios开发小技巧（转）

1.通过下面方式可以获取图片的像素颜色点：
- (void*)getImageData:(UIImage*)image
{
    void* imageData;
    if (imageData == NULL) 
        imageData = malloc(4 * image.size.width * image.size.height);
    
    CGColorSpaceRef cref = CGColorSpaceCreateDeviceRGB();
    CGContextRef gc = CGBitmapContextCreate(imageData,
                                            image.size.width,image.size.height,
                                            8,image.size.width*4,
                                            cref,kCGImageAlphaPremultipliedFirst);
    CGColorSpaceRelease(cref);
    UIGraphicsPushContext(gc);
    
    [image drawAtPoint:CGPointMake(0.0f, 0.0f)];
    
    UIGraphicsPopContext();
    CGContextRelease(gc);
    return imageData;
} 

 

2.UILabel和UITextField的小应用

    UILabel *LY_Label = [[UILabel alloc] initWithFrame:CGRectMake(60, 180, 60, 30)];
    [self.view addSubview:LY_Label];
    LY_Label.backgroundColor = [UIColor clearColor];
    LY_Label.text = @"密   码";
    LY_Label.font= [UIFont fontWithName:@"zapfino" size:(15.0f)]; //字体设置
   [[LY_Label layer] setBorderWidth:2.0f];  //边框设置

    UITextField *LY_Text = [[UITextField alloc] initWithFrame:CGRectMake(143, 180, 80, 30) ];
    [self.view addSubview:LY_Text];
    LY_Text.backgroundColor = [UIColor whiteColor];
    [LY_Text setBorderStyle:UITextBorderStyleLine];             //边框设置
    LY_Text.placeholder = @"password";                          //默认显示的字
    LY_Text.font = [UIFont fontWithName:@"helvetica" size:12];  //字体和大小设置
    LY_Text.textColor = [UIColor redColor];                     //设置字体的颜色
    LY_Text.clearButtonMode = UITextFieldViewModeWhileEditing;  //清空功能x
    LY_Text.returnKeyType = UIReturnKeyDone;                    //键盘有done

    LY_Text.secureTextEntry = YES;                              //密码输入时

   [LY_Text  becomeFirstResponder];                    //自动弹出软键盘

    LY_Text.delegate = self;                                    //托管

 

3.navigatrionbar 导航条设置颜色

   UINavigationBar *bar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320,44)];

     bar.tintColor = [UIColor blackColor];

   UINavigationItem *barItem = [[UINavigationItem alloc] initWithTitle:@""];

     [bar setItems:[NSArray arrayWithObjects:barItem,nil]];

   [baseView addSubview:bar];

4.AnnotationView的一些操作

- (MKAnnotationView *)mapView:(MKMapView *)aMapView viewForAnnotation:(id <MKAnnotation>)annotation { if(![annotation isKindOfClass:[MyAnnotation class]]) // Don't mess user location return nil; MKAnnotationView *annotationView = [aMapView dequeueReusableAnnotationViewWithIdentifier:@"spot"]; if(!annotationView) { annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"spot"]; annotationView.rightCalloutAccessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure]; [(UIButton *)annotationView.rightCalloutAccessoryView addTarget:self action:@selector(openSpot:) forControlEvents:UIControlEventTouchUpInside]; annotationView.enabled = YES; annotationView.canShowCallout = YES; annotationView.centerOffset = CGPointMake(7,-15); annotationView.calloutOffset = CGPointMake(-8,0); } // Setup annotation view annotationView.image = [UIImage imageNamed:@"pinYellow.png"]; // Or whatever return annotationView; }

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id )annotation {

    if (annotation == mapView.userLocation) {

        return nil;

    }

    MKPinAnnotationView *pinView = [[[MKPinAnnotationView alloc]initWithAnnotation:annotation reuseIdentifier:@"Pin"] autorelease];

    pinView.pinColor = MKPinAnnotationColorRed;

    pinView.canShowCallout = YES;

    pinView.rightCalloutAccessoryView = [UIButtonbuttonWithType:UIButtonTypeDetailDisclosure];

    pinView.animatesDrop = YES;

UIButton *button = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

button.frame = CGRectMake(0, 0, 25, 25);

[button setTitle:[NSStringstringWithFormat:@"%f,%f",self.touchCordinate.latitude,self.touchCordinate.longitude]forState:UIControlStateNormal];

pinView.rightCalloutAccessoryView = button;

    return pinView;

}

    

 

5.iphone开发----计算MKMapView的zoomlevel

计算地图的zoom level，如下：

 

#define MERCATOR_RADIUS 85445659.44705395

- (int)getZoomLevel:(MKMapView*)_mapView {

return 21-round(log2(_mapView.region.span.longitudeDelta * MERCATOR_RADIUS * M_PI / (180.0 * _mapView.bounds.size.width)));

}

 

我们可以写一个MKMapView的委托方法打印出zoom level

 

- (void)mapView:(MKMapView *)_mapView regionDidChangeAnimated:(BOOL)animated {

NSLog(@"zoom level %d", [self getZoomLevel:_mapView]);

}

结果范围在1-19之间，1就是全球地图。

 

6.在固定位置画一定大小的圈

UILongPressGestureRecognizer *lpress = [[UILongPressGestureRecognizer alloc]initWithTarget:self 

action:@selector(longPress:)];

lpress.minimumPressDuration = 0.3;//按0.5秒响应longPress方法

lpress.allowableMovement = 10.0;

//给MKMapView加上长按事件

[self._mapView addGestureRecognizer:lpress];//mapView是MKMapView的实例

[lpress release];

}

return self;

}

- (void)longPress:(UIGestureRecognizer*)gestureRecognizer {

    if (gestureRecognizer.state == UIGestureRecognizerStateBegan){  //这个状态判断很重要

        //坐标转换

        CGPoint touchPoint = [gestureRecognizer locationInView:self._mapView];

        CLLocationCoordinate2D touchMapCoordinate =

[self._mapView convertPoint:touchPoint toCoordinateFromView:self._mapView];

self.touchCoordinate = touchMapCoordinate;

NSLog(@"location:%f,%f",touchMapCoordinate.latitude,touchMapCoordinate.longitude);

if (nil != self.newAnnotation) {

[self._mapView removeAnnotation:self.newAnnotation];

}

self.newAnnotation = [Annotation annotationWithCoordinate:self.touchCoordinate];

self.newAnnotation.title = [NSStringstringWithFormat:@"%f,%f",self.touchCoordinate.latitude,self.touchCoordinate.longitude];

if (nil != self.newAnnotation) {

[self._mapView addAnnotation:self.newAnnotation];

[self locationcircle:self.touchCoordinate radius:[circleScaleText.text doubleValue]];

}

        //这里的touchMapCoordinate.latitude和touchMapCoordinate.longitude就是需要的经纬度，

        //NSString *url = [NSString stringWithFormat:@"http://maps.google.com/maps/api/geocode/json?latlng=%f,%f&sensor=false&region=sh&language=zh-CN", touchMapCoordinate.latitude, touchMapCoordinate.longitude];

        //[NSThread detachNewThreadSelector:@selector(loadMapDetailByUrl:) toTarget:self withObject:url];

    }

}

//在鼠标点击位置添加固定大小的圈

-(void)locationcircle:(CLLocationCoordinate2D)coordinate radius:(CLLocationDistance)circleradius {

    if (nil != self.locCircle) {

[self._mapView removeOverlay:locCircle];

}

locCircle = [MKCircle circleWithCenterCoordinate:coordinate radius:circleradius];

    [self._mapView addOverlay:locCircle]; 

}

//改变位置圈的大小

- (IBAction)changecircleScale{

[self dismissWithClickedButtonIndex:0 animated:YES];

[self locationcircle:self.touchCoordinate radius:[circleScaleText.text doubleValue]];

}

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation {

    if (annotation == mapView.userLocation) {

        return nil;

    }

    MKPinAnnotationView *pinView = [[[MKPinAnnotationView alloc]initWithAnnotation:annotation reuseIdentifier:@"Pin"] autorelease];

    pinView.pinColor = MKPinAnnotationColorRed;

    pinView.canShowCallout = YES;

    pinView.rightCalloutAccessoryView = [UIButtonbuttonWithType:UIButtonTypeDetailDisclosure];

    pinView.animatesDrop = YES;

UIButton *button = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

button.frame = CGRectMake(0, 0, 25, 25);

[button setTitle:[NSStringstringWithFormat:@"%f,%f",self.touchCoordinate.latitude,self.touchCoordinate.longitude]forState:UIControlStateNormal];

pinView.rightCalloutAccessoryView = button;

    return pinView;

}

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay

{

    if ([overlay isKindOfClass:[MKCircle class]])

    {

        MKCircleView* circleView = [[[MKCircleView alloc] initWithOverlay:overlay]autorelease];

        circleView.fillColor = [[UIColor cyanColor] colorWithAlphaComponent:0.2];

        circleView.strokeColor = [[UIColor blueColor] colorWithAlphaComponent:0.7];

        circleView.lineWidth = 3.0;

        return circleView;

    }

    

    return nil;

}

- (int)getZoomLevel:(MKMapView*)mapView {

return 21-round(log2(mapView.region.span.longitudeDelta * MERCATOR_RADIUS * M_PI / (180.0 * mapView.bounds.size.width)));

}

//一个MKMapView的委托方法控制zoomlevel

- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated {

//NSLog(@"zoom level %d", [self getZoomLevel:_mapView]);

}

- (void)setFrame:(CGRect)rect {

//[super setFrame:CGRectMake((320-rect.size.width)/2, 130, rect.size.width, 150)];

//self.center = CGPointMake(320/2, 480/2);

[super setFrame:CGRectMake(0, 20, 320, 460)];

}

- (void)layoutSubviews {

CGFloat buttonTop;

for (UIView *view in self.subviews) {

if ([[[view class] description] isEqualToString:@"UIThreePartButton"]) {

view.frame = CGRectMake(view.frame.origin.x, 

self.bounds.size.height - view.frame.size.height - 15, 

view.frame.size.width, 

view.frame.size.height);

buttonTop = view.frame.origin.y+200;

}

}

buttonTop -= 40;

NSLog(@"buttontop:%f",buttonTop);

circleLb.frame = CGRectMake(12, 50, 80, 30);

circleScaleText.frame = CGRectMake(100, 52, 150, 25);

changeBtn.frame = CGRectMake(260, 50, 40, 30);

}

7.mapView 定位当前位置使用CLLocationManager

#import "UserLoactionTestViewController.h"

@implementation UserLoactionTestViewController

- (void)loadView {

[super loadView];

mapView = [[MKMapView alloc] initWithFrame:CGRectMake(0, 10, 320, 400)];

[mapView setDelegate:self];

[mapView setMapType:MKMapTypeStandard];

[self.view addSubview:mapView];

[mapView release];

mapView.showsUserLocation=YES;

    CLLocationManager *locationManager = [[CLLocationManager alloc] init];//创建位置管理器 

    locationManager.delegate=self;//设置代理 

    locationManager.desiredAccuracy=kCLLocationAccuracyBest;//指定需要的精度级别 

//locationManager.distanceFilter=1000.0f;//设置距离筛选器 

    [locationManager startUpdatingLocation];//启动位置管理器 

    MKCoordinateSpan theSpan; 

    //地图的范围 越小越精确 

    theSpan.latitudeDelta= 0.05f; 

    theSpan.longitudeDelta=0.05f; 

    MKCoordinateRegion theRegion; 

CLLocationCoordinate2D cr  = locationManager.location.coordinate;

    theRegion.center = cr; //[[locationManager location] coordinate]; 

    theRegion.span = theSpan; 

    [mapView setRegion:theRegion]; 

//NSLog(@"%f  %f",mapView.userLocation.location.coordinate.latitude,

//   mapView.userLocation.location.coordinate.longitude);

}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {

//NSLog(@"dfdfdfd");

mapView.region = MKCoordinateRegionMake(newLocation.coordinate, MKCoordinateSpanMake(0.005f, 0.005f));

[manager stopUpdatingHeading];

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

}

- (void)viewDidUnload {

}

- (void)dealloc {

    [super dealloc];

}

@end

8.手指控制放大缩小(转的 没自己测验过,以后有需求的时候可以参考下)

        CGRect scrollFrame = CGRectMake(20,90,280,280);

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:scrollFrame];

scrollView.minimumZoomScale = 0.5;

scrollView.maximumZoomScale = 2.0;

scrollView.delegate = self;

UIImage *bigImage = [UIImage imageNamed:@"appleLogo.jpg"];

largeImageView = [[UIImageView alloc] initWithImage:bigImage];

[scrollView addSubview:largeImageView];

scrollView.contentSize = largeImageView.frame.size; //important!

[self.view addSubview:scrollView];

[scrollView release];

 

9.长按操作(转) (没尝试过,看到了,先收着)(跟上面地图的长按有点相似)

            UILongPressGestureRecognizer *longpressGesture = [[UILongPressGestureRecognizer alloc] init];

            longpressGesture.minimumPressDuration = 1;

            longpressGesture.cancelsTouchesInView = NO;

            [longpressGesture addTarget:self action:@selector(buttonLongPressed:)];

            [boxButton addGestureRecognizer:longpressGesture];

            [longpressGesture release];

 

11 resizeImage

http://www.iphonedevsdk.com/forum/iphone-sdk-development/7307-resizing-photo-new-uiimage.html

 

12 在mapview的特定位置上添加图片

CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(latitude, longitude);

MapAnnotation *annotation = [[MapAnnotationalloc] initWithcoordiante:coordinate];

[map_view addAnnotations: annotation];

[annotation release];

 

3.写文件的一种方法

NSData *dataToWrite = [s dataUsingEncoding: NSUTF8StringEncoding];

NSFileHandle* outputFile = [NSFileHandle fileHandleForWritingAtPath:Log_FilePath];

[outputFile seekToEndOfFile]; //可以在文件的末尾继续写下去

[outputFile writeData:dataToWrite];

 

实现pushViewController的自定义动画效果

CATransition *transition = [CATransition animation];

transition.duration = 1.0f;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = @"cube";
transition.subtype = kCATransitionFromRight;
transition.delegate = self;
[self.navigationController.view.layer addAnimation:transition forKey:nil];


DemoViewController *demoViewController = 
[[DemoViewController alloc]
initWithNibName:@"DemoViewController"
bundle:[NSBundle mainBundle]];
[self.navigationController pushViewController: demoViewController animated:YES]; 


[demoViewController release];