当我尝试在HTTP请求中发布图片时，我的应用程序崩溃了。我正在尝试将图像上传到服务器。崩溃似乎与我的自动释放池有关，因为崩溃被困在[pool release]消息中。
以下是崩溃报告：
#0 0x326712f8 in prepareForMethodLookup ()
#1 0x3266cf5c in lookUpMethod ()
#2 0x32668f28 in objc_msgSend_uncached ()
#3 0x33f70996 in NSPopAutoreleasePool ()
#4 0x33f82a6c in -[NSAutoreleasePool drain] ()
#5 0x00003d3e in -[CameraViewcontroller save:] (self=0x811400, _cmd=0x319c00d4, number=0x11e210) at /Users/hardikrathore/Desktop/LiveVideoRecording/Classes/CameraViewcontroller.m:266
#6 0x33f36f8a in __NSFireDelayedPerform ()
#7 0x32da44c2 in CFRunLoopRunSpecific ()
#8 0x32da3c1e in CFRunLoopRunInMode ()
#9 0x31bb9374 in GSEventRunModal ()
#10 0x30bf3c30 in -[UIApplication _run] ()
#11 0x30bf2230 in UIApplicationMain ()
#12 0x00002650 in main (argc=1, argv=0x2ffff474) at /Users/hardikrathore/Desktop/LiveVideoRecording/main.m:14
崩溃报告说下面代码的最后一行是崩溃的重点。 （第266行）
-(void)save:(id)number
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
j =[number intValue];
while(screens[j] != NULL){
NSLog(@" image made : %d",j);
UIImage * image = [UIImage imageWithCGImage:screens[j]];
image=[self imageByCropping:image toRect:CGRectMake(0, 0, 320, 240)];
NSData *imgdata = UIImageJPEGRepresentation(image,0.3);
[image release];
CGImageRelease(screens[j]);
screens[j] = NULL;
UIImage * image1 = [UIImage imageWithCGImage:screens[j+1]];
image1=[self imageByCropping:image1 toRect:CGRectMake(0, 0, 320, 240)];
NSData *imgdata1 = UIImageJPEGRepresentation(image1,0.3);
[image1 release];
CGImageRelease(screens[j+1]);
screens[j+1] = NULL;
NSString *urlString=@"http://www.test.itmate4.com/iPhoneToServerTwice.php";
// setting up the request object now
NSMutableURLRequest *request = [[NSMutableURLRequest alloc]init];
[request setURL:[NSURL URLWithString:urlString]];
[request setHTTPMethod:@"POST"];
NSString *fileName=[VideoID stringByAppendingString:@"_"];
fileName=[fileName stringByAppendingString:[NSString stringWithFormat:@"%d",k]];
NSString *fileName2=[VideoID stringByAppendingString:@"_"];
fileName2=[fileName2 stringByAppendingString:[NSString stringWithFormat:@"%d",k+1]];
/*
add some header info now
we always need a boundary when we post a file
also we need to set the content type
You might want to generate a random boundary.. this is just the same
as my output from wireshark on a valid html post
*/
NSString *boundary = [NSString stringWithString:@"---------------------------14737809831466499882746641449"];
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
[request addValue:contentType forHTTPHeaderField: @"Content-Type"];
/*
now lets create the body of the post
*/
//NSString *count=[NSString stringWithFormat:@"%d",front];;
NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
//[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; count=\"@\"";filename=\"%@.jpg\"\r\n",count,fileName] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"%@.jpg\"\r\n",fileName] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithData:imgdata]];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
//second boundary
NSString *string1 = [[NSString alloc] initWithFormat:@"\r\n--%@\r\n",boundary];
NSString *string2 =[[NSString alloc] initWithFormat:@"Content-Disposition: form-data; name=\"userfile2\"; filename=\"%@.jpg\"\r\n",fileName2];
NSString *string3 =[[NSString alloc] initWithFormat:@"\r\n--%@--\r\n",boundary];
[body appendData:[string1 dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[string2 dataUsingEncoding:NSUTF8StringEncoding]];
//experiment
//[body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile2\"; filename=\"%@.jpg\"\r\n",fileName2] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[NSData dataWithData:imgdata1]];
//[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[string3 dataUsingEncoding:NSUTF8StringEncoding]];
// setting the body of the post to the reqeust
[request setHTTPBody:body];
// now lets make the connection to the web
NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];
if([returnString isEqualToString:@"SUCCESS"])
{
NSLog(returnString);
k=k+2;
j=j+2;
[self performSelectorInBackground:@selector(save:) withObject:(id)[NSNumber numberWithInt:j]];
}
[imgdata release];
[imgdata1 release];
[NSThread sleepForTimeInterval:.01];
}
[pool drain]; //<-------------Line 266
}
我不明白是什么导致了崩溃。
答案 0 :(得分：1)
此处不需要自定义自动释放池。除非您一次保存几十个图像（不太可能），否则不需要本地池。
在循环之外创建自动释放池没有多大意义，因为循环包含整个方法。如果你确实需要一个自定义池，你应该把它放在循环中，这样它就可以清理每次循环中的内存。
崩溃可能与池没有直接关系，但这只是调试器捕获它的地方。要开始调试，请注释掉自动释放池及其排放。这可能会揭示崩溃的根源。
作为一个好的经验法则。在测试代码段并确定需要代码段之前，请不要创建本地池。只需要很少一个，然后只有在小范围内创建大量对象时才需要。
答案 1 :(得分：0)
根据您的崩溃报告，很难找出崩溃发生的原因。不确定是否可以使用NSLog获取一些调试信息（至少不在您的示例代码中）？ NSLog是一个将消息输出到输出控制台的功能。这是一个很棒的工具，可以找出崩溃的位置。