Uiview 可插拔自定义视图Nib(Nib-in-a-Nib):内存泄漏–;为什么?
我们目前的目标是:Uiview 可插拔自定义视图Nib(Nib-in-a-Nib):内存泄漏–;为什么?,uiview,memory-leaks,custom-controls,nib,nscoding,Uiview,Memory Leaks,Custom Controls,Nib,Nscoding,我们目前的目标是: 在Nib中构建自定义视图 在视图控制器中,以编程方式加载Nib,从加载的对象数组中获取自定义视图(我们在UIView类别方法+loadInstanceFromNib中执行此操作) 将自定义视图添加为子视图,设置其边框 实际上,我们希望将自定义视图Nib“嵌入”到视图控制器Nib中。否则,至少我们希望在视图控制器Nib中添加并定位自定义视图实例(而不查看其内容) 我们非常接近于以下解决方案: @implementation CustomView static BOOL loa
+loadInstanceFromNib
中执行此操作)@implementation CustomView
static BOOL loadNormally;
- (id) initWithCoder:(NSCoder*)aDecoder {
id returnValue = nil;
if (loadNormally) { // Step 2
returnValue = [super initWithCoder:aDecoder];
loadNormally = !loadNormally;
} else { // Step 1
loadNormally = !loadNormally;
returnValue = [CustomView loadInstanceFromNib];
}
return returnValue;
}
- (id) initWithFrame:(CGRect)frame {
loadNormally = YES;
self = (id) [[CustomView loadInstanceFromNib] retain];
self.frame = frame;
return self;
}
// ...
@end
如果我们以编程方式实例化自定义视图,我们将使用-initWithFrame:
,它将从Nib加载视图(它将调用-initWithCoder:
,并直接转到标记为“步骤2”的If分支),设置其帧,并将其保留计数设置为1
但是,如果我们在视图控制器Nib中实例化自定义视图,静态loadNormal
变量(公认相当难看)最初是NO
:我们从“步骤1”开始,在确保立即使用“normal”后,加载并返回从其Nib加载的实例如果-initWithCoder:
的分支。从自定义视图Nib加载意味着我们回到-initWithCoder:
,这次是loadnormal==YES
,也就是说,我们让Nib加载机制完成它的工作并返回自定义视图实例
结果总结如下:
- 好的:它有效!!!我们在Interface Builder中有“可插拔”自定义视图李>
- 坏:一个丑陋的静态变量…:-/
- 丑陋:自定义视图的实例泄漏!这就是我想要你帮助的地方——我不明白为什么。有什么想法吗
-awakefter,将从视图控制器Nib加载的对象替换为从“嵌入式”Nib(CustomView.xib)加载的对象
我在一篇博文中写道
代码是这样的:
// CustomView.m
- (id) awakeAfterUsingCoder:(NSCoder*)aDecoder {
BOOL theThingThatGotLoadedWasJustAPlaceholder = ([[self subviews] count] == 0);
if (theThingThatGotLoadedWasJustAPlaceholder) {
// load the embedded view from its Nib
CustomView* theRealThing = [[[NSBundle mainBundle] loadNibNamed:NSStringFromClass([CustomView class]) owner:nil options:nil] objectAtIndex:0];
// pass properties through
theRealThing.frame = self.frame;
theRealThing.autoresizingMask = self.autoresizingMask;
[self release];
self = [theRealThing retain];
}
return self;
}
杨的答案很好。。。但“发送到解除分配实例的消息”仍然会发生。我通过“自我”分配解决了这个问题
因此,如果使用ARC,则必须允许这种“自我”分配。(阅读了解更多信息)
要在ARC项目中实现这一点,请在文件中添加“-fno objc ARC”标志编译器设置。
然后在此文件中进行无弧编码(如dealoc设置nils、调用super dealoc等)
此外,客户端nib的viewcontroller应该使用strong属性来保存awakeFromNib返回的实例。在我的示例代码中,customView的引用方式如下:
// CustomView.m
- (id) awakeAfterUsingCoder:(NSCoder*)aDecoder {
BOOL theThingThatGotLoadedWasJustAPlaceholder = ([[self subviews] count] == 0);
if (theThingThatGotLoadedWasJustAPlaceholder) {
// load the embedded view from its Nib
CustomView* theRealThing = [[[NSBundle mainBundle] loadNibNamed:NSStringFromClass([CustomView class]) owner:nil options:nil] objectAtIndex:0];
// pass properties through
theRealThing.frame = self.frame;
theRealThing.autoresizingMask = self.autoresizingMask;
[self release];
self = [theRealThing retain];
}
return self;
}
@属性(strong,非原子)IBOutlet CustomView*CustomView
最后,我使用在我的UIView+Util类别中定义的copyupropertiesto:和loadNibNamed对属性处理和nib加载添加了一些其他改进
所以使用编码器后醒来:代码现在是
#import "UIView+Util.h"
...
- (id) awakeAfterUsingCoder:(NSCoder*)aDecoder
{
// are we loading an empty “placeholder” or the real thing?
BOOL theThingThatGotLoadedWasJustAPlaceholder = ([[self subviews] count] == 0);
if (theThingThatGotLoadedWasJustAPlaceholder)
{
CustomView* customView = (id) [CustomView loadInstanceFromNib];
// copy all UI properties from self to new view!
// if not, property that were set using Interface buider are lost!
[self copyUIPropertiesTo:customView];
[self release];
// need retain to avoid deallocation
self = [customView retain];
}
return self;
}
UIView+Util类别代码为
@interface UIView (Util)
+(UIView*) loadInstanceFromNib;
-(void) copyUIPropertiesTo:(UIView *)view;
@end
以及它的实施
#import "UIView+Util.h"
#import "Log.h"
@implementation UIView (Util)
+(UIView*) loadInstanceFromNib
{
UIView *result = nil;
NSArray* elements = [[NSBundle mainBundle] loadNibNamed: NSStringFromClass([self class]) owner: nil options: nil];
for (id anObject in elements)
{
if ([anObject isKindOfClass:[self class]])
{
result = anObject;
break;
}
}
return result;
}
-(void) copyUIPropertiesTo:(UIView *)view
{
// reflection did not work to get those lists, so I hardcoded them
// any suggestions are welcome here
NSArray *properties =
[NSArray arrayWithObjects: @"frame",@"bounds", @"center", @"transform", @"contentScaleFactor", @"multipleTouchEnabled", @"exclusiveTouch", @"autoresizesSubviews", @"autoresizingMask", @"clipsToBounds", @"backgroundColor", @"alpha", @"opaque", @"clearsContextBeforeDrawing", @"hidden", @"contentMode", @"contentStretch", nil];
// some getters have 'is' prefix
NSArray *getters =
[NSArray arrayWithObjects: @"frame", @"bounds", @"center", @"transform", @"contentScaleFactor", @"isMultipleTouchEnabled", @"isExclusiveTouch", @"autoresizesSubviews", @"autoresizingMask", @"clipsToBounds", @"backgroundColor", @"alpha", @"isOpaque", @"clearsContextBeforeDrawing", @"isHidden", @"contentMode", @"contentStretch", nil];
for (int i=0; i<[properties count]; i++)
{
NSString * propertyName = [properties objectAtIndex:i];
NSString * getter = [getters objectAtIndex:i];
SEL getPropertySelector = NSSelectorFromString(getter);
NSString *setterSelectorName =
[propertyName stringByReplacingCharactersInRange:NSMakeRange(0,1) withString:[[propertyName substringToIndex:1] capitalizedString]];
setterSelectorName = [NSString stringWithFormat:@"set%@:", setterSelectorName];
SEL setPropertySelector = NSSelectorFromString(setterSelectorName);
if ([self respondsToSelector:getPropertySelector] && [view respondsToSelector:setPropertySelector])
{
NSObject * propertyValue = [self valueForKey:propertyName];
[view setValue:propertyValue forKey:propertyName];
}
}
}
#导入“UIView+Util.h”
#导入“Log.h”
@实现UIView(Util)
+(UIView*)loadInstanceFromNib
{
UIView*结果=零;
NSArray*元素=[[NSBundle mainBundle]loadNibNamed:NSStringFromClass([self class])所有者:nil选项:nil];
用于(id元素中的对象)
{
if([anObject isKindOfClass:[self class]]))
{
结果=一个对象;
打破
}
}
返回结果;
}
-(void)copyUIPropertiesTo:(UIView*)视图
{
//反射无法获取这些列表,所以我硬编码了它们
//欢迎提出任何建议
NSArray*属性=
[NSArray阵列包含以下对象:@“框架”@“边界”@“中心”@“变换”@“内容缩放因子”@“多重接触”@“排他性接触”@“自动ResizesSuBViews”@“自动ResisingMask”@“剪贴簿”@“背景色”@“alpha”@“不透明”@“在绘图前清除内容”@“隐藏”@“内容模式”@“内容拉伸”,零];
//某些getter具有“is”前缀
NSArray*吸气剂=
[n包含以下对象的阵列阵列:@“帧”@“边界”@“中心”@“变换”@“内容缩放因子”@“isMultipleTouchEnabled”@“isExclusiveTouch”@“autoresizesSubviews”@“autoresizingMask”@“clipsToBounds”@“backgroundColor”@“alpha”@“等水线”@“在绘图之前清除内容”@“isHidden”@“内容模式”@“内容拉伸”,零];
对于(int i=0;i有另一种方法:
假设您在界面生成器中使用View1
,然后创建另一个名为View2
,View2
有一个相应的View2.xib
文件,您已经链接了View2.m
和View2.xib
中的插座
然后,在View1.m
中,写下以下内容:
-(void)awakeFromNib
{
NSArray *topObjects = [[NSBundle mainBundle] loadNibNamed:NSStringFromClass([self class]) owner:nil options:nil];
self.subContentView = topObjects.firstObject]
[self addSubview:self.subContentView];
}
有了它,您可以在需要将自定义视图放入Interface Builder
的地方使用View1
,从而使View1
在Interface Builder
中可重用,而无需再编写任何代码。接下来,这将在ARC下工作:我喜欢提取属性复制到方法的想法(这使得它可以被子类覆盖)。请注意,该技术在ARC下确实有效,正如我最后在后续帖子中所描述的:@Yang great,我将尽快尝试:-)