如何更改自定義NSTextfield的drawRect中的文本顏色

Question

我使用NSTextfield的自己的類OMNTextfield子類來顯示文本，並在文本長度大於控件寬度時為文本設置動畫。

該文字在iTunes中像歌曲標題一樣動畫。 它就像一個魅力！

現在我想更改文本的顏色和文本對齊方式。 我已經搜索了一下setTextcolor，setAlignment，viewWillDraw，cellClass，...但沒有任何工作=>我的文字仍然是黑色的！

你可以在這里找到完整的代碼（Xcode項目）

我的問題：如何更改NSTextfield子類中的文本顏色/對齊方式？

根據這篇文章 ，下面的代碼應該可以工作，但事實並非如此！

-(void)viewWillDraw { // or whatever is the Appkit equivalent
      [super setTextColor:[NSColor redColor]];
}

完整代碼：

//
//  OMNTextField.h


#import <Cocoa/Cocoa.h>

@interface OMNTextField : NSTextField {
    NSTimer * scroller;
    NSPoint point;
    NSString * text;
    NSTimeInterval speed;
    CGFloat stringWidth;
}

- (void) setText:(NSString *)newText;

@property (nonatomic, copy) NSString * text;
@property (nonatomic) NSTimeInterval speed;

@end

//
//  OMNTextField.m

#import "OMNTextField.h"

@implementation OMNTextField

@synthesize text;
@synthesize speed;


- (void) dealloc {
    [text release];
    [scroller invalidate];
    [super dealloc];
}

- (void) setText:(NSString *)newText {
    NSLog(@"[%@ %@] *** ", NSStringFromClass([self class]), NSStringFromSelector(_cmd));
    [text release];
    text = [newText copy];
    point = NSZeroPoint;

    stringWidth = [newText sizeWithAttributes:nil].width;

    if (scroller == nil && speed > 0 && text != nil) {
        scroller = [NSTimer scheduledTimerWithTimeInterval:speed target:self selector:@selector(moveText:) userInfo:nil repeats:YES];
    }
}

- (void) setSpeed:(NSTimeInterval)newSpeed {
    if (newSpeed != speed) {
        speed = newSpeed;

        [scroller invalidate];
        if (speed > 0 && text != nil) {
            scroller = [NSTimer scheduledTimerWithTimeInterval:speed target:self selector:@selector(moveText:) userInfo:nil repeats:YES];
        }
    }
}

-(void)viewWillDraw {
    [super setTextColor:[NSColor yellowColor]];
}


- (void) moveText:(NSTimer *)timer {
    if (stringWidth >= self.frame.size.width)
        point.x = point.x - 1.0f;

    [self setNeedsDisplay:YES];
}

- (void)drawRect:(NSRect)dirtyRect {
    CGFloat max;

    if (stringWidth >= dirtyRect.size.width)
        max = stringWidth;
    else
        max = dirtyRect.size.width;

    if (point.x + stringWidth < 0) {
        point.x += max ;
    }

    [text drawAtPoint:point withAttributes:nil];

    if (point.x < 0) {
        NSPoint otherPoint = point;
        otherPoint.x += max;
        [text drawAtPoint:otherPoint withAttributes:nil];
    }

}

@end
//
//  AppDelegate.h

#import <Cocoa/Cocoa.h>
#import "OMNTextField.h"

@interface AppDelegate : NSObject <NSApplicationDelegate>
{
}


@property (assign) IBOutlet OMNTextField *label2;
@property (assign) IBOutlet OMNTextField *label3;
@property (assign) IBOutlet NSWindow *window;
@property (assign) IBOutlet NSView *view;

@end

//
//  AppDelegate.m


#import "AppDelegate.h"

@implementation AppDelegate

- (void)dealloc
{
    [super dealloc];
}

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{

    [self.label2 setText:@"Too shoort no need to move"];
    [self.label2 setSpeed:0.05];


    [self.label3 setText:@"Text Lenght > TextField.width => Automatically animate text to show all"];
    [self.label3 setSpeed:0.05];
}

@end

PS：我的代碼基於Dave Delong代碼： iTunes Song Title Scrolling in Cocoa

Answer 1

更換線

[text drawAtPoint:point withAttributes:nil];

同

NSColor *color = [NSColor greenColor]; \\put something else here...
NSDictionary *attributes = [NSDictionary dictionaryWithObject:color forKey:NSForegroundColorAttributeName];
[text drawAtPoint:point withAttributes:attributes];

Answer 2

如上所述，Nate Chandler使用NSDictionary *屬性作為文本顏色。

關於文本對齊，我設法通過計算drawAtPoint：point的良好值來居中文本

我們擁有所有需要的信息stringWidth和控制NSTextfield寬度來計算drawAtPoint中的變量點的良好值：point