明天給大家帶來一個自定義的儀表盤，效果圖如下。

Demo中用到了 QuartzCore類 首先承繼一個UIView。

// Gauge.h 
// GaugeDemo 
// 
// Created by 海鋒 周 on 12-3-27. 
// Copyright (c) 2012年 CJLU rights reserved. 
// 
 
#import <UIKit/UIKit.h> 
#import <QuartzCore/QuartzCore.h> 
 
@interface Gauge : UIView 
{ 
  UIImage *gaugeView; 
  UIImageView *pointer; 
   
  CGFloat maxNum; 
  CGFloat minNum; 
   
  CGFloat maxAngle; 
  CGFloat minAngle; 
   
  CGFloat gaugeValue; 
  CGFloat gaugeAngle; 
   
  CGFloat angleperValue; 
  CGFloat scoleNum; 
   
  NSMutableArray *labelArray; 
  CGContextRef context; 
} 
 
@property (nonatomic,retain) UIImage *gaugeView; 
@property (nonatomic,retain) UIImageView *pointer; 
@property (nonatomic,retain) NSMutableArray *labelArray; 
@property (nonatomic) CGContextRef context; 
-(void)setGaugeValue:(CGFloat)value animation:(BOOL)isAnim; 
 
@end

指針的旋轉是經過QuartzCore.framework中的CATransform3DRotate 來完成的，所以一定要記得把框架添加出去。當然在旋轉之前，我們還需求把指針的中心pointer.layer.anchorPoint 挪動到你需求的轉動中心。

在設置旋轉動畫的時分，我們用的不是CABaseAnimiation 而是用  CAKeyframeAnimation。這是由於假如運用中的 toValue 來完成旋轉的話，它默許是以最小的旋轉的，假如要完成控制旋轉的方向的話，我們就只能用關鍵幀來設置旋轉的途徑。用關鍵幀的益處還有一個，就是可以給指針添加，旋轉到指定地位當前的左右擺動的效果。

繪制儀表盤是經過Quartz2D來完成的，首先我們需求用UIGraphicsGetCurrentContext函數來獲取一個Context上下文，就是相當於獲取一個畫布。然後就可以在下面經過三角函數的計算，畫出背景圖片，和下面的刻度線了。

// Gauge.m 
// GaugeDemo 
// 
// Created by 海鋒 周 on 12-3-27. 
// Copyright (c) 2012年 CJLU. All rights reserved. 
// 
 
#import "Gauge.h" 
#import <QuartzCore/QuartzCore.h> 
 
#define MAXOFFSETANGLE 120.0f 
#define POINTEROFFSET 90.0f 
#define MAXVALUE    120.0f 
#define CELLMARKNUM  5 
#define CELLNUM    12 
#define GAUGESTRING  @"單位:Km/h" 
#define DEFLuaTSIZE  300     
/************************************************ 
  儀表盤的大小不建議設置的太小。 
  長寬都是300是最合適的 
  假如要更小的需求自行修正刻度長度和文字大小 
              ---powered by 周海鋒 
                2012-3-29 
 ***********************************************/ 
 
 
@implementation Gauge 
 
@interface Gauge (private) 
- (CGFloat) parseToX:(CGFloat) radius Angle:(CGFloat)angle; 
- (CGFloat) parseToY:(CGFloat) radius Angle:(CGFloat)angle; 
- (CGFloat) transToRadian:(CGFloat)angel; 
- (CGFloat) parseToAngle:(CGFloat) val; 
- (CGFloat) parseToValue:(CGFloat) val; 
- (void)setTextLabel:(NSInteger)labelNum; 
- (void)setLineMark:(NSInteger)labelNum; 
- (void) pointToAngle:(CGFloat) angle Duration:(CGFloat) duration; 
@end 
 
@synthesize gaugeView,pointer,context; 
@synthesize labelArray; 
 
- (id)initWithFrame:(CGRect)frame 
{ 
  self = [super initWithFrame:frame]; 
  if (self) { 
    //設置背景通明 
    [self setBackgroundColor:[UIColor clearColor]]; 
     
    scoleNum = DEFLuaTSIZE/frame.size.width; 
    maxNum = MAXVALUE; 
    minNum = 0.0f; 
    minAngle = -MAXOFFSETANGLE; 
    maxAngle = MAXOFFSETANGLE; 
    gaugeValue = 0.0f; 
    gaugeAngle = -MAXOFFSETANGLE; 
    angleperValue = (maxAngle - minAngle)/(maxNum - minNum); 
     
    gaugeView= [UIImage imageNamed:@"gaugeback.png"]; 
    //添加指針 
    UIImage *_pointer = [UIImage imageNamed:@"pointer2.png"]; 
    pointer = [[UIImageView alloc] initWithImage:_pointer]; 
    pointer.layer.anchorPoint = CGPointMake(0.5, 0.78); 
    pointer.center = self.center; 
    pointer.transform = CGAff.netransformMakeScale(scoleNum, scoleNum); 
    [self addSubview:pointer]; 
    //設置文字標簽 
    [self setTextLabel:CELLNUM]; 
    //設置指針到0地位 
    pointer.layer.transform = CATransform3DMakeRotation([self transToRadian:-MAXOFFSETANGLE], 0, 0, 1); 
  } 
  return self; 
} 
 
/* 
 * setTextLabel 繪制刻度值 
 * @labelNum NSInteger 刻度值的數目 
 */ 
-(void)setTextLabel:(NSInteger)labelNum 
{ 
   labelArray = [NSMutableArray arrayWithCapacity:labelNum]; 
   
  CGFloat textDis = (maxNum - minNum)/labelNum; 
  CGFloat angelDis = (maxAngle - minAngle)/labelNum; 
  CGFloat radius = (self.center.x - 75)*scoleNum; 
  CGFloat currentAngle; 
  CGFloat currentText = 0.0f; 
  CGPoint centerPoint = self.center; 
   
  for(int i=0;i<=labelNum;i++) 
  { 
    currentAngle = minAngle + i * angelDis - POINTEROFFSET; 
    currentText = minNum + i * textDis; 
    UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(0 , 0 , 30, 50)]; 
    label.autoresizesSubviews = YES; 
    label.textColor = [UIColor whiteColor]; 
    label.backgroundColor = [UIColor clearColor]; 
    //設置刻度的文字的格式 
    if(i<labelNum/2){ 
      label.textAlignment = UITextAlignmentLeft; 
    }else if (i==labelNum/2){ 
      label.textAlignment = UITextAlignmentCenter; 
    }else{ 
      label.textAlignment = UITextAlignmentRight; 
    } 
    label.text = [NSString stringWithFormat:@"%d",(int)currentText]; 
    label.center = CGPointMake(centerPoint.x+[self parseToX:radius Angle:currentAngle],centerPoint.y+[self parseToY:radius Angle:currentAngle]); 
     
    [labelArray addObject:label]; 
    [self addSubview:label];     
  } 
  // 設置刻度表的稱號 
  UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(0 , 0 ,100, 40)]; 
  label.autoresizesSubviews = YES; 
  label.textColor = [UIColor whiteColor]; 
  label.backgroundColor = [UIColor clearColor]; 
  label.textAlignment = UITextAlignmentCenter; 
  label.text = GAUGESTRING; 
  label.center = CGPointMake(centerPoint.x,centerPoint.y*3/2); 
  [self addSubview:label];   
} 
 
/* 
 * setLineMark 繪制刻度的標志 
 * @labelNum NSInteger 刻度是數目 
 */ 
-(void)setLineMark:(NSInteger)labelNum 
{ 
 
  CGFloat angelDis = (maxAngle - minAngle)/labelNum; 
  CGFloat radius = self.center.x; 
  CGFloat currentAngle; 
  CGPoint centerPoint = CGPointMake(self.frame.size.width/2, self.frame.size.height/2); 
   
  for(int i=0;i<=labelNum;i++) 
  { 
    currentAngle = minAngle + i * angelDis - POINTEROFFSET; 
    //給刻度標志繪制不同的顏色 
    if(i>labelNum*2/3) 
    { 
      CGContextSetStrokeColorWithColor(context, [[UIColor colorWithRed:1 green:0 blue:0 alpha:0.8] CGColor]); 
    }else if(i>labelNum*1/3){ 
      CGContextSetStrokeColorWithColor(context, [[UIColor colorWithRed:1 green:1 blue:0 alpha:0.8] CGColor]); 
    }else{ 
      CGContextSetStrokeColorWithColor(context, [[UIColor colorWithRed:0 green:1 blue:0 alpha:0.8] CGColor]); 
    } 
    //繪制不同的長短的刻度 
    if(i%5==0) 
    {    
      CGContextSetLineCap(context, kCGLineCapSquare); 
      CGContextSetLineWidth(context, 3); 
      CGContextStrokePath(context);   
      CGContextMoveToPoint(context,centerPoint.x+[self parseToX:radius-25*scoleNum Angle:currentAngle], centerPoint.y+[self parseToY:radius-25*scoleNum Angle:currentAngle]); 
      CGContextAddL.netoPoint(context,centerPoint.x+[self parseToX:radius-65*scoleNum Angle:currentAngle], centerPoint.y+[self parseToY:radius-65*scoleNum Angle:currentAngle]); 
    }else{ 
      CGContextSetLineWidth(context, 2); 
      CGContextSetLineCap(context, kCGLineCapSquare); 
      CGContextStrokePath(context);  
      CGContextMoveToPoint(context,centerPoint.x+[self parseToX:radius-25*scoleNum Angle:currentAngle], centerPoint.y+[self parseToY:radius-25*scoleNum Angle:currentAngle]); 
      CGContextAddL.netoPoint(context,centerPoint.x+[self parseToX:radius-40*scoleNum Angle:currentAngle], centerPoint.y+[self parseToY:radius-40*scoleNum Angle:currentAngle]);   
    } 
  } 
} 
 
/* 
 * setGaugeValue 挪動到某個數值 
 * @value CGFloat 挪動到的數值 
 * @isAnim BOOL  能否執舉動畫 
 */ 
-(void)setGaugeValue:(CGFloat)value animation:(BOOL)isAnim 
{ 
  CGFloat tempAngle = [self parseToAngle:value]; 
  gaugeValue = value; 
  //設置轉動時間和轉動動畫 
  if(isAnim){ 
    [self pointToAngle:tempAngle Duration:0.6f]; 
  }else 
  { 
    [self pointToAngle:tempAngle Duration:0.0f]; 
  } 
} 
 
/* 
 * pointToAngle 按角度旋轉 
 * @angel CGFloat 角度 
 * @duration CGFloat 動畫執行時間 
 */ 
- (void) pointToAngle:(CGFloat) angle Duration:(CGFloat) duration 
{ 
  CAKeyframeAnimation *anim=[CAKeyframeAnimation animationWithKeyPath:@"transform"];  
  NSMutableArray *values=[NSMutableArray array];  
  anim.duration = duration; 
  anim.autoreverses = NO; 
  anim.fillMode = kCAFillModeForwards; 
  anim.removedOnCompletion= NO; 
   
  CGFloat distance = angle/10; 
  //設置轉動途徑，不能直接用 CABaseAnimation 的toValue，那樣是按最短途徑的，轉動超越180度時無法控制方向 
  int i = 1; 
  for(;i<=10;i++){ 
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DRotate(CATransform3DIdentity, [self transToRadian:(gaugeAngle+distance*i)], 0, 0, 1)]]; 
    } 
  //添加緩動效果 
   [values addObject:[NSValue valueWithCATransform3D:CATransform3DRotate(CATransform3DIdentity, [self transToRadian:(gaugeAngle+distance*(i))], 0, 0, 1)]]; 
   [values addObject:[NSValue valueWithCATransform3D:CATransform3DRotate(CATransform3DIdentity, [self transToRadian:(gaugeAngle+distance*(i-2))], 0, 0, 1)]];    
   [values addObject:[NSValue valueWithCATransform3D:CATransform3DRotate(CATransform3DIdentity, [self transToRadian:(gaugeAngle+distance*(i-1))], 0, 0, 1)]]; 
                                       
  anim.values=values; ; 
  [pointer.layer addAnimation:anim forKey:@"cubeIn"]; 
   
  gaugeAngle = gaugeAngle+angle; 
   
} 
 
/* 
 * parseToX 角度轉弧度 
 * @angel CGFloat 角度 
 */ 
-(CGFloat)transToRadian:(CGFloat)angel 
{ 
  return angel*M_PI/180; 
} 
 
 
/* 
 * parseToX 依據角度，半徑計算X坐標 
 * @radius CGFloat 半徑  
 * @angle CGFloat 角度 
 */ 
- (CGFloat) parseToX:(CGFloat) radius Angle:(CGFloat)angle 
{ 
  CGFloat tempRadian = [self transToRadian:angle]; 
  return radius*cos(tempRadian); 
} 
 
/* 
 * parseToY 依據角度，半徑計算Y坐標 
 * @radius CGFloat 半徑  
 * @angle CGFloat 角度 
 */ 
- (CGFloat) parseToY:(CGFloat) radius Angle:(CGFloat)angle 
{ 
  CGFloat tempRadian = [self transToRadian:angle]; 
  return radius*sin(tempRadian); 
} 
 
/* 
 * parseToAngle 依據數據計算需求轉動的角度 
 * @val CGFloat 要挪動到的數值 
 */ 
-(CGFloat) parseToAngle:(CGFloat) val 
{ 
  //異常的數據 
  if(val<minNum){ 
    return minNum; 
  }else if(val>maxNum){ 
    return maxNum; 
  } 
  CGFloat temp =(val-gaugeValue)*angleperValue; 
  return temp; 
} 
 
/* 
 * parseToValue 依據角度計算數值 
 * @val CGFloat 要挪動到的角度 
 */ 
-(CGFloat) parseToValue:(CGFloat) val 
{ 
  CGFloat temp=val/angleperValue; 
  CGFloat temp2=maxNum/2+temp; 
  if(temp2>maxNum){ 
    return maxNum; 
  }else if(temp2<maxNum){ 
    return maxNum; 
  } 
  return temp2; 
} 
 
- (void)drawRect:(CGRect)rect  
{ 
  //獲取上下文 
  context = UIGraphicsGetCurrentContext(); 
  //設置背景通明 
  CGContextSetFillColorWithColor(context,self.backgroundColor.CGColor); 
  CGContextFillRect(context, rect); 
  //繪制儀表背景   
  [[self gaugeView ]draWinRect:self.bounds]; 
  //繪制刻度 
  [self setLineMark:CELLNUM*CELLMARKNUM]; 
     
  CGContextStrokePath(context); 
} 
 
@end 

Demo的下載地址：http://xiazai.jb51.net/201701/yuanma/GaugeDemo_jb51.rar

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