实例iPhone编程入门教程-第十一天

DAY ELEVEN – PlumbBob

今天来建立一个 iPhone app 软件，用你的iPhone 当作测量水平器。



纲要：

- 在程序显示前运行代码 -

- 加入QUartzCore Frameworks -

- 关于iPhone的“Utility Application” 运用 -

- UIAccelerometer (加速度检波器) 代码运用 -

首先运行以安装好的 xCode

选择: File->New Project.

从 "New Project" 窗口

选择 : iPhone OS ->Applications-> Utility Application

命名 : 我这里命名为 “PlumbBob”

(1) 在xCode右键点击 Frameworks ->Add->Existing Framework;在Frameworks文件夹下选择 QuartzCore.framework,
按Add






(2) 导入下面图片文件

下载下面图片，放入 PlumbBob 文件夹内并命名为下面名称

PlumbBob.png



在xCode下右键点击 PlumbBob->Add->Existing Files; 在 PlumbBob 文件夹内，选择下载好的图片，按 Add

(3) 在xCode打开 MainView.h 文件,加入下面代码

#import <UIKit/UIKit.h>

@interface MainViewController : UIViewController <UIAccelerometerDelegate> {

UIImageView* plumbBobView;

}

- (void)rotatePlumbStringToDegree:(CGFloat)positionInDegrees;

@end

CGFloat DegreesToRadians(CGFloat degrees);

CGFloat RadiansToDegrees(CGFloat radians);

(4) 在xCode打开 MainView.m 文件,加入下面代码

#import "MainViewController.h"

#import "MainView.h"

#import <QuartzCore/QuartzCore.h>

// Constant for the number of times per second (Hertz) to sample acceleration.

#define kAccelerometerFrequency 40

@implementation MainViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {

if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {

// Custom initialization

}

return self;

}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.

- (void)viewDidLoad {

// 设置背景色为黑色

self.view.backgroundColor = [UIColor blackColor];

// 设置 "测锤" 图案

UIImage* image = [UIImage imageNamed:@"PlumbBob.png"];

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

// 移动锚点到底部节拍器区域中间

plumbBobView.layer.anchorPoint = CGPointMake(0.5, 0.0);

//确定锚点后设置帧，显示的将会在正确启动位置.

plumbBobView.frame = CGRectMake(self.view.frame.size.width/2 - 20, 0, 40, 450);

[self.view addSubview:plumbBobView];

[plumbBobView release];

// 配置和启动加速度检波器

[[UIAccelerometer sharedAccelerometer] setUpdateInterval:(1.0 / kAccelerometerFrequency)];

[[UIAccelerometer sharedAccelerometer] setDelegate:self];

}

// Override to allow orientations other than the default portrait orientation.

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {

// Return YES for supported orientations

return (interfaceOrientation == UIInterfaceOrientationPortrait);

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview

// Release anything that's not essential, such as cached data

}

- (void)dealloc {

[plumbBobView release];

[super dealloc];

}

#pragma mark -

#pragma mark === Accelerometer delegate ===

#pragma mark -

// UIAccelerometerDelegate method, 当设备加速时呼出.

- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {

[self rotatePlumbStringToDegree:-acceleration.x* 30];

}

#pragma mark -

#pragma mark === Swing the plumb and string ===

#pragma mark -

- (void)rotatePlumbStringToDegree:(CGFloat)positionInDegrees {

[plumbBobView.layer removeAllAnimations];

CATransform3D rotationTransform = CATransform3DIdentity;

rotationTransform = CATransform3DRotate(rotationTransform, DegreesToRadians(positionInDegrees), 0.0, 0.0, 1.0);

plumbBobView.layer.transform = rotationTransform;

}

@end

CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;};

CGFloat RadiansToDegrees(CGFloat radians) {return radians * 180/M_PI;};

最后在 xCode 选择 Build->Build and Go; Save All.

下载今天教程文件:

PlumbBob.zip