我正在为iOS开发一款应用。这是一场游戏。
在游戏界面中,用户可以从UIImageView加载对象子类。为了保存游戏,我开发了这个函数,它按主视图的子视图数组进行迭代,并生成一个XML字符串。
#pragma mark I/O Functions
-(NSString *)getXMLFromItemsView:(UIView *)items
{
int a;
NSString *XML = [[[NSString alloc] init] autorelease];
XML = [XML stringByAppendingString:@"<PAGE>"];
for (a=0;a<[items.subviews count];a++)
{
iItem *item = [items.subviews objectAtIndex:a];
if ([item isKindOfClass:[iItem class]] || [item isKindOfClass:[iText class]])
{
NSLog(@"INFO -> Saving...Item Id: %d",item.itemId);
XML = [XML stringByAppendingString:@"<ITEM>\n"];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<CLASS>%@</CLASS>\n",[item class]]];
//OriginalTransform
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalTransform.a>%f</originalTransform.a>\n",item.originalTransform.a]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalTransform.b>%f</originalTransform.b>\n",item.originalTransform.b]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalTransform.c>%f</originalTransform.c>\n",item.originalTransform.c]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalTransform.d>%f</originalTransform.d>\n",item.originalTransform.d]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalTransform.tx>%f</originalTransform.tx>\n",item.originalTransform.tx]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalTransform.ty>%f</originalTransform.ty>\n",item.originalTransform.ty]];
//InitialTransform
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<initialTransform.a>%f</initialTransform.a>\n",item.initialTransform.a]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<initialTransform.b>%f</initialTransform.b>\n",item.initialTransform.b]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<initialTransform.c>%f</initialTransform.c>\n",item.initialTransform.c]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<initialTransform.d>%f</initialTransform.d>\n",item.initialTransform.d]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<initialTransform.tx>%f</initialTransform.tx>\n",item.initialTransform.tx]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<initialTransform.ty>%f</initialTransform.ty>\n",item.initialTransform.ty]];
//OriginalFrame
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalFrame.x>%f</originalFrame.x>\n",item.originalFrame.origin.x]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalFrame.y>%f</originalFrame.y>\n",item.originalFrame.origin.y]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalFrame.w>%f</originalFrame.w>\n",item.originalFrame.size.width]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<originalFrame.h>%f</originalFrame.h>\n",item.originalFrame.size.height]];
//zOrder
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<zOrder>%d</zOrder>\n",item.zOrder]];
//itemId
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<itemId>%d</itemId>\n",item.itemId]];
//itemIdColor
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<itemIdColor>%d</itemIdColor>\n",item.itemIdColor]];
//itemIdTexture
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<itemIdTexture>%d</itemIdTexture>\n",item.itemIdTexture]];
//itemIdStyle
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<itemIdStyle>%d</itemIdStyle>\n",item.itemIdStyle]];
//textureLevel
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<textureLevel>%d</textureLevel>\n",item.textureLevel]];
//currentSizePercent
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentSizePercent>%f</currentSizePercent>\n",item.currentSizePercent]];
//currentRotation
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentRotation>%f</currentRotation>\n",[item currentRotation]]];
//holdItem
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<holdItem>%d</holdItem>\n",item.holdItem]];
//isInverted
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<isInverted>%d</isInverted>\n",item.isInverted]];
//isMerged
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<isMerged>%d</isMerged>\n",item.isMerged]];
//selectedFrame
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<selectedFrame>%@</selectedFrame>\n",item.selectedFrame]];
//mergedFrame
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<mergedFrame>%@</mergedFrame>\n",item.mergedFrame]];
//NSLog(@"Item Saved Frame: X:%f Y:%f W:%f H:%f",item.frame.origin.x,item.frame.origin.y,item.frame.size.width,item.frame.size.height);
//currentFrame
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentFrame.x>%f</currentFrame.x>\n",item.frame.origin.x]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentFrame.y>%f</currentFrame.y>\n",item.frame.origin.y]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentFrame.w>%f</currentFrame.w>\n",item.frame.size.width]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentFrame.h>%f</currentFrame.h>\n",item.frame.size.height]];
//currentBounds
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentBounds.x>%f</currentBounds.x>\n",item.bounds.origin.x]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentBounds.y>%f</currentBounds.y>\n",item.bounds.origin.y]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentBounds.w>%f</currentBounds.w>\n",item.bounds.size.width]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentBounds.h>%f</currentBounds.h>\n",item.bounds.size.height]];
//currentTransform
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentTransform.a>%f</currentTransform.a>\n",item.transform.a]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentTransform.b>%f</currentTransform.b>\n",item.transform.b]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentTransform.c>%f</currentTransform.c>\n",item.transform.c]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentTransform.d>%f</currentTransform.d>\n",item.transform.d]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentTransform.tx>%f</currentTransform.tx>\n",item.transform.tx]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentTransform.ty>%f</currentTransform.ty>\n",item.transform.ty]];
if ([[NSString stringWithFormat:@"%@",[item class]] isEqual:@"iText"])
{
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<currentText>%@</currentText>\n",[item text]]];
}
XML = [XML stringByAppendingString:@"</ITEM>\n"];
}
}
if (fondo)
{
XML = [XML stringByAppendingString:@"<FONDO>\n"];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<selectedFrame>%@</selectedFrame>",fondo.selectedFrame]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<picturePath>%@</picturePath>",fondo.picturePath]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<idCurrentColor>%d</idCurrentColor>",fondo.idCurrentColor]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<idCurrentTexture>%d</idCurrentTexture>",fondo.idCurrentTexture]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<idCurrentStyle>%d</idCurrentStyle>",fondo.idCurrentStyle]];
XML = [XML stringByAppendingString:[NSString stringWithFormat:@"\t<textureLevel>%d</textureLevel>",fondo.textureLevel]];
XML = [XML stringByAppendingString:@"</FONDO>\n"];
}
XML = [XML stringByAppendingString:@"</PAGE>"];
NSLog(@"INFO -> ItemsViewXML: %@",XML);
return XML;
}
目前,如果要迭代的项目数量低于20,则此方法可以正常工作。但是当它必须处理超过50个项目时,应用程序崩溃,因为内存。
我使用仪器调试了这个方法,并且检测到没有泄漏,但分配增加直到使用大量RAM。
创建一个字符串使用超过100MB的VM是不正常的。
任何人都知道我在失去什么?
感谢。
答案 0 :(得分:2)
首先,您没有创建 a 字符串,您当前正在为每个对象创建O(50)个字符串。这是非常低效的 - 在空间上(正如你在你的内存使用中看到的那样)和暂时的(它应该花费很多时间)。
所以你可以使用Mattias˚建议,并使用你可以附加数据的可变字符串。
这将解决您所看到的很多内存压力问题,但仍然会很慢:
解析格式字符串相对耗时,并且保存操作应该尽可能快。
因此,让我们忽略症状并查看问题:
你基本上想要一个对象层次结构的存档,对吗?
在自定义类中,实施-initWithCoder:
和-encodeWithCoder:
。
然后您的保存操作变得像
一样简单NSData *encodedObjectGraph = [NSKeyedArchiver archivedDataWithRootObject:yourObjectGraphsRootGoesHere];
NSError *saveError;
if ([encodedObjectGraph writeToURL:storeURL options:NSDataWritingAtomic error:&saveError])
return;
NSLog(@"Uh oh: %@", saveError);
并且您的加载操作仅变为
NSError *loadError;
NSData *savedObjectData = [NSData dataWithContentsOfURL:storeURL options:0 error:&loadError];
if (!savedObjectData) {
NSLog(@"No data at %@: %@", storeURL, loadError);
return;
}
objectGraphRoot = [NSKeyedUnarchiver unarchiveRootObjectWithData:savedObjectData];
(注意unarchiveRootObjectWithData:
返回一个自动释放的对象!)
答案 1 :(得分:1)
从部件构建字符串时,您应该使用NSMutableString
。
NSMutableString *xml = [NSMutableString string];
[xml appendFormat:@"....", ...];
[xml appendFormat:@"....", ...];
但在这种情况下,您甚至可能希望使用正确的XML序列化程序,如NSXMLDocument
等。