ARC代碼轉換 - 此NumberRef更改是否正確？

Question

我使用沒有與ARC編譯了下面的代碼行，我需要轉換了，當我升級我的項目現有的庫：

CFAttributedStringSetAttribute(text, 
    CFRangeMake(position, length), 
    kCTStrokeWidthAttributeName, 
    [NSNumber numberWithFloat:[[attributes objectForKey:@"stroke"] intValue]]); 

與ARC編譯的過程中產生了一些錯誤，我修改了代碼以使其更加合規。代碼更改是否正確？

int strokeInt = [[attributes objectForKey:@"stroke"] intValue]; 
CFNumberRef strokeNumber = CFNumberCreate(NULL, kCFNumberSInt32Type, &strokeInt); 

CFAttributedStringSetAttribute(text, 
    CFRangeMake(position, length), 
    kCTStrokeWidthAttributeName, 
    strokeNumber); 

任何意見，將不勝感激。

Answer 1

你在泄漏strokeNumber，除非你打電話給CFRelease就可以了。但是CFNumber是免費電話與NSNumber橋接，這樣可以消除strokeNumber，只是使用強制：

CFAttributedStringSetAttribute(text, 
    CFRangeMake(position, length), 
    kCTStrokeWidthAttributeName, 
    (__bridge CFNumberRef)[NSNumber numberWithFloat:[[attributes objectForKey:@"stroke"] intValue]]); 

此外，如果[attributes objectForKey:@"stroke"]正好已經是一個NSNumber，可以簡化到只此：

CFAttributedStringSetAttribute(text, 
    CFRangeMake(position, length), 
    kCTStrokeWidthAttributeName, 
    (__bridge CFNumberRef)[attributes objectForKey:@"stroke"]);