添加Core Plot饼图作为子视图 - 饼图未被绘制

Question

是iOS编程和Core Plot的新手。我正在使用XCode 4.2和iOS 5，并使用iOS模拟器测试iPhone应用程序。

我知道我在这里忽略了一些东西（在这一天突破了我的头脑并且经常尝试google'并尝试了各种可能的解决方案，都是徒劳的）。有人可以帮忙或指点一下吗？

我试图做一些非常简单的事情 - ＆gt;添加饼图（使用Core Plot完成）作为子视图。最初，我将饼图显示为模态视图＆amp;它工作得很好。现在，在同一个视图中我想添加几个按钮，所以我创建了一个视图（按下按钮时会显示），我在其中添加了2个按钮，并尝试添加此饼图。按钮显示正常，但饼图不可见！

这是名为“GraphView”的视图的XIB文件，当按下按钮时会显示该文件：

在上面的屏幕截图中，突出显示的视图“View”是一个UIView对象，我想在其中显示饼图。整个视图'GraphView'显示正常;出现两个按钮，但我添加到子视图的饼图却没有。我在上图中作为子视图添加的UIView对象也可以正常显示（我通过为它设置背景颜色来检查它）。这是代码：

GRAPHVIEW.H

#import <UIKit/UIKit.h>
#import "PieChartView.h"

@interface GraphView : UIViewController

    @property (strong, nonatomic) PieChartView *pieChartView;
    // gView is the view which is linked to the 'UIView' subview in IB
    // in the above figure
    @property (strong, nonatomic) IBOutlet UIView *gView;
    @property (strong, nonatomic) IBOutlet UIButton *buttonBack;
    @property (strong, nonatomic) IBOutlet UIButton *buttonMail;

    -(void) setHistoryData:(NSArray *)history;
    ...
    ...
@end

GRAPHVIEW.M

...
...
@synthesize gView;
@synthesize buttonBack;
@synthesize buttonMail;
...
...
-(void) setHistoryData:(NSArray *)history {
    NSLog(@"GraphView: setHistoryData");
    [pieChartView setHistoryData:history];
    [gView addSubview:pieChartView];
}


- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  if (self) {
      // Custom initialization
  }
  pieChartView = [[PieChartView alloc] init];
  return self;
}
...
...

#pragma mark - 查看生命周期

- (void)viewDidLoad
{
  NSLog(@"GraphView: viewDidLoad");
  [super viewDidLoad];

  [pieChartView initializeGraph];
}

- (void)viewDidUnload
{
  [super viewDidUnload];
  // Release any retained subviews of the main view.
  // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
  // Return YES for supported orientations
  return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

@end

PIECHARTVIEW.H 这是绘制饼图的那个（它应该'画'）饼图！

#import <UIKit/UIKit.h>
#import "CorePlot-CocoaTouch.h"

// I tied subclassing 'UIViewController' or just 'UIView'...all in vain
@interface PieChartView : CPTGraphHostingView <CPTPlotDataSource> {
   CPTXYGraph *graph;
   CPTPieChart *pieChart;
}

@property (nonatomic, retain) CPTXYGraph *graph;

-(void) initializeGraph;
-(void) initializePieChart;
-(void) setHistoryData:(NSArray *)history;

@end

PIECHARTVIEW.m

...
@implementation PieChartView

@synthesize graph;

NSArray *historyData;


// I added the NSLog to see if these get called, but they don't seem to get called!
// So, this means that the pie chart is not being drawn actually!
-(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot {
     NSLog(@"numberOfRecordsForPlot: History count: %d", (int)[historyData count]);
     return [historyData count];
}


 // This too isn't getting called
-(NSNumber *) numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index {   
    NSLog(@"historyView: numberForPlot");
    return [historyData objectAtIndex:index];
}


// This too is not getting called! OMG!
-(CPTLayer *)dataLabelForPlot:(CPTPlot *)plot recordIndex:(NSUInteger)index {
   NSLog(@"HistoryView: dataLabelForPlot");
   ...
}


// This method is getting called. Am seeing the log messages
-(void) initializeGraph {

   NSLog(@"HistoryView: initializeGraph");

   graph = [[CPTXYGraph alloc] init];

   CPTTheme *theme = [CPTTheme themeNamed:kCPTDarkGradientTheme];
   [graph applyTheme:theme];

  CPTGraphHostingView *hostingView = (CPTGraphHostingView *) self;
  hostingView.hostedGraph = graph;  
  //hostingView.bounds = CGRectMake(5, 5, 70, 70);
  [self initializePieChart];  
}


// This method is also getting called. I see the log messages from this method too
/** 
 * Initialize the pie chart for display
 */
-(void) initializePieChart {

  NSLog(@"HistoryView: initializePieChart");
  pieChart = [[CPTPieChart alloc] init];
  pieChart.dataSource = self;
  pieChart.pieRadius = 100.0;
  pieChart.opaque = FALSE;
  //pieChart.pieRadius = 60;
  pieChart.shadowOffset = CGSizeMake(-1, 1);
  pieChart.identifier = @"PieChart";
  pieChart.startAngle = M_PI_4;
  pieChart.sliceDirection = CPTPieDirectionCounterClockwise;
  pieChart.labelOffset = -0.6;
  [graph addPlot:pieChart];
  NSLog(@"added pie chart to the graph view");
}


// This also is getting called
-(void) setHistoryData:(NSArray *)history {
    NSLog(@"HistoryView: setHistoryData");
    historyData = history;
}

...
...
@end

Answer 1

您不需要gView属性。删除它并将pieChartView声明更改为：

@property (strong, nonatomic) IBOutlet PieChartView *pieChartView;

将自定义视图链接到此属性而不是gView，并将IB中的类更改为PieChartView。同时从-initWithNibName:bundle:中删除此属性的初始化 - 当加载nib时，视图将自动初始化。