ios开发基础知识 － 2

移动物体

CABasicAnimation *theAnimation;    
theAnimation=[CABasicAnimation animationWithKeyPath:@"transform.translation.x"];
theAnimation.duration=1;
theAnimation.repeatCount=2;
theAnimation.autoreverses=YES;
theAnimation.fromValue=[NSNumber numberWithFloat:0];
theAnimation.toValue=[NSNumber numberWithFloat:-60];
[view.layer addAnimation:theAnimation forKey:@"animateLayer"]; 

参考：

Field Key Path	Description
rotation.x	The rotation, in radians, in the x axis.
rotation.y	The rotation, in radians, in the y axis.
rotation.z	The rotation, in radians, in the z axis.
rotation	The rotation, in radians, in the z axis. This is identical to setting the rotation.z field.
scale.x	Scale factor for the x axis.
scale.y	Scale factor for the y axis.
scale.z	Scale factor for the z axis.
scale	Average of all three scale factors.
translation.x	Translate in the x axis.
translation.y	Translate in the y axis.
translation.z	Translate in the z axis.
translation	Translate in the x and y axis. Value is an NSSize or CGSize.

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访问别的类的属性或者方法

myAppDelegate *appDelegate
     = (myAppDelegate *)[[UIApplication sharedApplication] delegate];
[[[appDelegate rootViewController] flipsideViewController] myMethod];

---

遍历子视图

for (UIImageView *anImage in [self.view subviews]) {
     if (anImage.tag == 1) {
          // do something
     }
}

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播放音乐

	// 设置音乐文件路径
path = [[NSBundle mainBundle] pathForResource:@"mani" ofType:@"mp3"];

	// 判断是否可以访问这个文件
if ([[NSFileManager defaultManager] fileExistsAtPath:path]) 
{    
		// 设置 player
	player = [[AVAudioPlayer alloc] initWithContentsOfURL:
			  [NSURL fileURLWithPath:path] error:nil];
	
		// 调节音量 (范围从0到1)
	player.volume = 0.4f;
	
		// 准备buffer，减少播放延时的时间      
	[player prepareToPlay];
	
		// 设置播放次数，0为播放一次，负数为循环播放
	[player setNumberOfLoops:-1];
	
	[player play];    
	
}	

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随机数

rand()

例：

[_cloud02 setFrame:CGRectMake(-1024+rand()%600, -768+rand()%300, 2048, 1536)];
[_cloud01 setFrame:CGRectMake(-1024+rand()%600, -768+rand()%300, 2048, 1536)];

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Timer

每秒调用

[NSTimer scheduledTimerWithTimeInterval:1
     target:self
     selector:@selector(myMethod)
     userInfo:nil
     repeats:YES];

如果需要传递参数的话：

[NSTimer scheduledTimerWithTimeInterval:1     target:self
     selector:@selector(myMethod)
     userInfo:myObject
     repeats:YES];

 

-(void)myMethod:(NSTimer*)timer {
     // Now I can access all the properties and methods of myObject
     [[timer userInfo] myObjectMethod];
}

停止Timer

[myTimer invalidate]; 
myTimer = nil;

---

时间

CFAbsoluteTime myCurrentTime = CFAbsoluteTimeGetCurrent();

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在模拟器里测试 App 的加速度感应功能

在模拟器里可以用鼠标点击模拟 iPhone 的触摸操作，但重力感应（比如用户倾斜机身来操控飞机/赛车）怎么模拟？按住 command 再按左右方向键，就能在电脑模拟器上测试加速度感应了。