有一个小的Toast实用程序源代码(https://github.com/Joyfl/JLToast)，它似乎使用ARC。但是我想在手动保留释放(MRR)模式下使用它。
特别是，我不确定center = [[JLToastCenter alloc] init];的+(id)defaultCenter中的JLToastCenter.m(用于ARC模式)是否应该重写为center = [[[JLToastCenter alloc] init] autorelease];(用于MRR模式)，其中center声明为static id center = nil;。
在此post中，@ mipadi给出的答案是:“如果变量仅初始化一次，并且应在应用程序的整个生命周期内保持不变，则否，则不应释放它(它的内存实际上将在释放时释放。应用程序退出，无论如何)”。我猜这是当center中的静态变量JLToastCenter.m但不确定的情况。
下面列出的我自己的MRR模式版本添加了release / autorelease / dealloc功能。我还将所有点符号都更改为消息传递样式。
源代码
源代码列表:JLToastCenter.hJLToastCenter.mJLToast.hJLToast.mJLToastView.hJLToastView.mJLToastCenter.h文件:
#import <Foundation/Foundation.h>
@class JLToast;
@interface JLToastCenter : NSObject
{
NSOperationQueue *_queue;
}
+ (id)defaultCenter;
- (void)addToast:(JLToast *)toast;
@end
JLToastCenter.m文件:#import "JLToastCenter.h"
#import "JLToast.h"
@implementation JLToastCenter
+ (id)defaultCenter
{
static id center = nil;
static dispatch_once_t onceToken; // It makes singleton object thread-safe
dispatch_once(&onceToken, ^{
center = [[[JLToastCenter alloc] init] autorelease]; // Added autorelease by me, originally as center = [[JLToastCenter alloc] init];
[[NSNotificationCenter defaultCenter] addObserver:center selector:@selector(deviceOrientationDidChange:) name:UIDeviceOrientationDidChangeNotification object:nil];
});
return center;
}
// Added by me
- (void)dealloc
{
[_queue release];
[super dealloc];
}
- (id)init
{
self = [super init];
if( self )
{
_queue = [[NSOperationQueue alloc] init];
[_queue setMaxConcurrentOperationCount:1];
}
return self;
}
- (void)addToast:(JLToast *)toast
{
[_queue addOperation:toast];
}
- (void)deviceOrientationDidChange:(id)sender
{
if( [[_queue operations] count] )
{
[[[[_queue operations] objectAtIndex:0] view] layoutSubviews];
}
}
@end
JLToast.h文件:#import <UIKit/UIKit.h>
#define JLToastShortDelay 2.0f
#define JLToastLongDelay 3.5f
@class JLToastView;
@interface JLToast : NSOperation
{
BOOL _isExecuting;
BOOL _isFinished;
}
@property (nonatomic, strong) JLToastView *view;
@property (nonatomic, copy) NSString *text; // added by me
@property (nonatomic) NSTimeInterval delay;
@property (nonatomic) NSTimeInterval duration;
+ (id)makeText:(NSString *)text;
+ (id)makeText:(NSString *)text duration:(NSTimeInterval)duration;
+ (id)makeText:(NSString *)text delay:(NSTimeInterval)delay duration:(NSTimeInterval)duration;
- (void)show;
- (void)cancel;
@end
JLToast.m文件:#import "JLToast.h"
#import "JLToastView.h"
#import "JLToastCenter.h"
#import <dispatch/dispatch.h>
@implementation JLToast
@synthesize view = _view; // added by me
@synthesize text = _text; // added by me
+ (id)makeText:(NSString *)text
{
return [JLToast makeText:text delay:0 duration:JLToastShortDelay];
}
+ (id)makeText:(NSString *)text duration:(NSTimeInterval)duration
{
return [JLToast makeText:text delay:0 duration:duration];
}
+ (id)makeText:(NSString *)text delay:(NSTimeInterval)delay duration:(NSTimeInterval)duration
{
JLToast *toast = [[[JLToast alloc] init] autorelease]; // added autorelease by me
[toast setText:text];
[toast setDelay:delay];
[toast setDuration:duration];
return toast;
}
// added by me
- (void)dealloc
{
[_view release];
[_text release];
[super dealloc];
}
- (id)init
{
self = [super init];
if( self )
{
_view = [[JLToastView alloc] init];
}
return self;
}
- (void)show
{
[[JLToastCenter defaultCenter] addToast:self];
}
- (void)cancel
{
}
#pragma mark -
#pragma mark Getter/Setter
- (NSString *)text
{
return [[_view textLabel] text];
}
- (void)setText:(NSString *)text
{
[[_view textLabel] setText:text];
// [_view layoutSubviews];
}
#pragma mark -
#pragma mark NSOperation Overriding
- (BOOL)isConcurrent
{
return YES;
}
- (void)start
{
if( ![NSThread isMainThread] )
{
[self performSelectorOnMainThread:@selector(start) withObject:nil waitUntilDone:NO];
return;
}
[super start];
}
- (void)main{
[self willChangeValueForKey:@"isExecuting"];
_isExecuting = YES;
[self didChangeValueForKey:@"isExecuting"];
dispatch_async(dispatch_get_main_queue(), ^{ // Non-main thread cannot modify user interface
[_view layoutSubviews]; // Calls layoutSubviews before being-shown. added by the original creator devxoul at around 20131013
[_view setAlpha:0];
[[[UIApplication sharedApplication] keyWindow] addSubview:_view];
[UIView animateWithDuration:0.5 delay:_delay options:UIViewAnimationOptionBeginFromCurrentState animations:^{
[_view setAlpha:1];
} completion:^(BOOL finished) {
[UIView animateWithDuration:_duration animations:^{
[_view setAlpha:1.0001];
} completion:^(BOOL finished) {
[self finish];
[UIView animateWithDuration:0.5 animations:^{
[_view setAlpha:0];
}];
}];
}];
});
}
- (void)finish
{
[self willChangeValueForKey:@"isExecuting"];
[self willChangeValueForKey:@"isFinished"];
_isExecuting = NO;
_isFinished = YES;
[self didChangeValueForKey:@"isExecuting"];
[self didChangeValueForKey:@"isFinished"];
}
- (BOOL)isExecuting
{
return _isExecuting;
}
- (BOOL)isFinished
{
return _isFinished;
}
@end
JLToastView.h文件:#import <UIKit/UIKit.h>
@interface JLToastView : UIView
@property (nonatomic, strong) UIView *backgroundView;
@property (nonatomic, strong) UILabel *textLabel;
@property (nonatomic) UIEdgeInsets textInsets;
@end
JLToastView.m文件:#import "JLToastView.h"
#import <QuartzCore/CALayer.h>
#define JLTOAST_LABEL_FONT_SIZE ((UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) ? 12 : 16)
#define JLTOAST_OFFSET_PORTRAIT_Y ((UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) ? 30 : 60)
#define JLTOAST_OFFSET_LANDSCAPE_Y ((UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) ? 20 : 40)
@implementation JLToastView
// added by congliu at 20131031Thu 1000am
- (void)dealloc
{
[_backgroundView release];
[_textLabel release];
[super dealloc];
}
- (id)init
{
self = [super init];
if( self )
{
_backgroundView = [[UIView alloc] initWithFrame:CGRectMake( 0, 0, 100, 100 )];
[_backgroundView setBackgroundColor:[UIColor colorWithWhite:0 alpha:0.7]];
[[_backgroundView layer] setCornerRadius:5];
[_backgroundView setClipsToBounds:YES];
[self addSubview:_backgroundView];
_textLabel = [[UILabel alloc] initWithFrame:CGRectMake( 0, 0, 100, 100 )];
[_textLabel setTextColor:[UIColor whiteColor]];
[_textLabel setBackgroundColor:[UIColor clearColor]];
[_textLabel setFont:[UIFont systemFontOfSize:JLTOAST_LABEL_FONT_SIZE]];
[_textLabel setNumberOfLines:0];
[self addSubview:_textLabel];
_textInsets = UIEdgeInsetsMake( 6, 10, 6, 10 );
}
return self;
}
- (void)layoutSubviews
{
[super layoutSubviews];
CGFloat deviceWidth = [[UIScreen mainScreen] bounds].size.width;
UIFont *font = [_textLabel font];
CGSize constraintSize = CGSizeMake( deviceWidth * (280.0f/320.0f), INT_MAX );
CGSize textLabelSize = [[_textLabel text] sizeWithFont:font constrainedToSize:constraintSize lineBreakMode:NSLineBreakByWordWrapping];
[_textLabel setFrame:CGRectMake( _textInsets.left, _textInsets.top, textLabelSize.width, textLabelSize.height )];
[_backgroundView setFrame:CGRectMake( 0, 0,
[_textLabel frame].size.width + _textInsets.left + _textInsets.right,
[_textLabel frame].size.height + _textInsets.top + _textInsets.bottom )];
NSInteger x, y, width, height;
CGFloat angle;
switch( [[UIDevice currentDevice] orientation] )
{
case UIDeviceOrientationPortraitUpsideDown:
width = [_backgroundView frame].size.width;
height = [_backgroundView frame].size.height;
x = ([[UIScreen mainScreen] bounds].size.width - width) / 2;
y = JLTOAST_OFFSET_PORTRAIT_Y;
angle = M_PI;
break;
case UIDeviceOrientationLandscapeLeft:
width = [_backgroundView frame].size.height;
height = [_backgroundView frame].size.width;
x = JLTOAST_OFFSET_LANDSCAPE_Y;
y = ([[UIScreen mainScreen] bounds].size.height - height) / 2;
angle = M_PI_2;
break;
case UIDeviceOrientationLandscapeRight:
width = [_backgroundView frame].size.height;
height = [_backgroundView frame].size.width;
x = [[UIScreen mainScreen] bounds].size.width - width - JLTOAST_OFFSET_LANDSCAPE_Y;
y = ([[UIScreen mainScreen] bounds].size.height - height) / 2;
angle = -M_PI_2;
break;
default:
width = [_backgroundView frame].size.width;
height = [_backgroundView frame].size.height;
x = ([[UIScreen mainScreen] bounds].size.width - width) / 2;
y = [[UIScreen mainScreen] bounds].size.height - height - JLTOAST_OFFSET_PORTRAIT_Y;
angle = 0;
break;
}
[self setTransform:CGAffineTransformMakeRotation( angle )];
[self setFrame:CGRectMake( x, y, width, height )];
}
#pragma mark - hit test
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
// NSLog(@"%@ hitTest", [self class]);
return nil;
}
@end
最佳答案
摆脱自动发布![JLToastCenter defaultCenter]应该始终返回相同的对象。第一次调用它时，它将创建对象。 (之所以称为“惰性初始化”，是因为仅在需要时才创建对象)，然后它将指向共享对象的指针存储在静态变量中以使其保持不变。
如果要添加autorelease，则将在下一次当前的autoreleasepool耗尽时创建并释放该对象。然后，静态变量将包含指向已释放对象的指针。下次您再调用[JLToastCenter defaultCenter]，然后向已发布的对象发送消息时，可能会发生各种事情(您的应用程序可能会崩溃)。
关于ios - 如何在非ARC模式下手动释放此静态变量，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19752081/