iTunes歌曲 [英] iTunes Song Title Scrolling in Cocoa

问题描述

我进行了广泛的搜索，不能为我的生活找到任何有关如何实现类似效果的iTunes歌曲标题滚动，如果文本太大的Cocoa。我已经尝试设置NSTextField的边界无效。我已经尝试使用NSTextView以及各种尝试使用NSScrollView。我相信我错过了一些简单的东西，但任何帮助将非常感谢。我也希望不要使用CoreGraphics，如果可能的话。

I have searched extensively and cannot for the life of me find any information about how to achieve a similar effect to that of the iTunes song title scrolling if the text is too large in Cocoa. I have tried setting the bounds on a NSTextField to no avail. I have tried using NSTextView as well as various attempts at using NSScrollView. I am sure I am missing something simple but any help would be greatly appreciated. I am also hoping to not have to use CoreGraphics if at all possible.

示例，请注意Base.FM http：// www 。文本已滚动。如果你需要一个更好的例子打开iTunes与一个相当大的标题的歌曲，并观看它来回滚动。

Example, notice the "Base.FM http://www." text has been scrolled. If you need a better example open iTunes with a song with a rather large title and watch it scroll back and forth.

我认为有一个简单的方法

I would think surely there is a simple way to just create a marquee type effect with an NSTextField and an NSTimer, but alas.

推荐答案

我可以看到这将是很困难，如果你是一个NSTextField和NSTimer， 试图将功能集成到现有的控制中。但是，如果你只是开始一个纯NSView，这不是那么糟糕。我在大约10分钟后就鞭打这个...

I can see how this would be difficult if you're trying to shoehorn the functionality into an exist control. However, if you just start with a plain NSView, it's not that bad. I whipped this up in about 10 minutes...

//ScrollingTextView.h:
#import <Cocoa/Cocoa.h>
@interface ScrollingTextView : NSView {
    NSTimer * scroller;
    NSPoint point;
    NSString * text;
    NSTimeInterval speed;
    CGFloat stringWidth;
}

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

@end


//ScrollingTextView.m

#import "ScrollingTextView.h"

@implementation ScrollingTextView

@synthesize text;
@synthesize speed;

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

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

- (void) moveText:(NSTimer *)timer {
    point.x = point.x - 1.0f;
    [self setNeedsDisplay:YES];
}

- (void)drawRect:(NSRect)dirtyRect {
    // Drawing code here.

    if (point.x + stringWidth < 0) {
        point.x += dirtyRect.size.width;
    }

    [text drawAtPoint:point withAttributes:nil];

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

@end

在Interface Builder中将NSView拖动到您的窗口上，并将其类更改为ScrollingTextView。然后（在代码中），你做：

Just drag an NSView onto your window in Interface Builder and change its class to "ScrollingTextView". Then (in code), you do:

[myScrollingTextView setText:@"This is the text I want to scroll"];
[myScrollingTextView setSpeed:0.01]; //redraws every 1/100th of a second

这显然很基础，周围的东西，你正在寻找，是一个合适的地方开始。

This is obviously pretty rudimentary, but it does the wrap around stuff that you're looking for and is a decent place to start.

这篇关于iTunes歌曲的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！