我试图在地图视图中添加注释。每个注释代表一条推文。我从twitter api获取每条推文的坐标。应用程序在加载地图后立即崩溃。而且我不确定为什么。
编辑：这是相关代码的当前版本。它运行正常，直到它发送tweetLocation为null的推文。然后它崩溃了。
STTwitterAPI *twitter = [STTwitterAPI twitterAPIAppOnlyWithConsumerKey:@"key" consumerSecret:@"secret"];
[twitter verifyCredentialsWithSuccessBlock:^(NSString *username) {
[twitter getSearchTweetsWithQuery:@"apple" geocode:geoCode lang:nil locale:nil resultType:@"recent" count:@"10" until:nil sinceID:nil maxID:nil includeEntities:nil callback:nil successBlock:^(NSDictionary *searchMetadata, NSArray *statuses) {
tweetsArray = [NSMutableArray arrayWithArray:statuses];
NSLog(@"tweetsArray: %@", tweetsArray);
for (int i = 0; i < [tweetsArray count]; i++) {
NSDictionary *t = tweetsArray[i];
tweetAnnotation = [[MKPointAnnotation alloc]init];
NSArray *tweetLocation = [[t valueForKey:@"geo"]valueForKey:@"coordinates"];
NSLog(@"Tweet Location: %@", tweetLocation);
if ([tweetLocation count] == 0) {
continue;
}
else {
double lat = [[tweetLocation objectAtIndex:0]doubleValue];
double longitude = [[tweetLocation objectAtIndex:1]doubleValue];
locationCoord.latitude = lat;
locationCoord.longitude = longitude;
twitterName = [t valueForKeyPath:@"user.screen_name"];
NSLog(@"Twitter name: %@", twitterName);
tweetAnnotation.title = twitterName;
tweetAnnotation.coordinate = locationCoord;
[tweetLocationsArray addObject:tweetAnnotation];
}
}
[tweetMap addAnnotations:tweetLocationsArray];
} errorBlock:^(NSError *error) {
NSLog(@"%@", error.debugDescription);
}];
} errorBlock:^(NSError *error) {
NSLog(@"%@", error.debugDescription);
}];
编辑：这是控制台中的当前错误：
2014-10-07 08:00:36.278 Tweets By Location[5244:382886] Tweet Location: (
"37.33158914",
"-122.03076495"
)
2014-10-07 08:00:36.278 Tweets By Location[5244:382886] Twitter name: tofuhunter
2014-10-07 08:00:36.278 Tweets By Location[5244:382886] Tweet Location: (
"37.33161957",
"-122.03080173"
)
2014-10-07 08:00:36.278 Tweets By Location[5244:382886] Twitter name: treynesss
2014-10-07 08:00:36.278 Tweets By Location[5244:382886] Tweet Location: (
"37.33161957",
"-122.03080173"
)
2014-10-07 08:00:36.279 Tweets By Location[5244:382886] Twitter name: mattlarowe
2014-10-07 08:00:36.279 Tweets By Location[5244:382886] Tweet Location: <null>
2014-10-07 08:00:36.279 Tweets By Location[5244:382886] -[NSNull count]: unrecognized selector sent to instance 0x10b0accb0
2014-10-07 08:00:36.281 Tweets By Location[5244:382886] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSNull count]: unrecognized selector sent to instance 0x10b0accb0'
*** First throw call stack:
(
0 CoreFoundation 0x000000010ae043f5 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x000000010aa9dbb7 objc_exception_throw + 45
2 CoreFoundation 0x000000010ae0b50d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x000000010ad637fc ___forwarding___ + 988
4 CoreFoundation 0x000000010ad63398 _CF_forwarding_prep_0 + 120
5 Tweets By Location 0x000000010a08876e __32-[MapViewController viewDidLoad]_block_invoke_2 + 542
6 Tweets By Location 0x000000010a029feb __147-[STTwitterAPI getSearchTweetsWithQuery:geocode:lang:locale:resultType:count:until:sinceID:maxID:includeEntities:callback:successBlock:errorBlock:]_block_invoke + 203
7 Tweets By Location 0x000000010a01cd1a __99-[STTwitterAPI getResource:baseURLString:parameters:downloadProgressBlock:successBlock:errorBlock:]_block_invoke117 + 186
8 Tweets By Location 0x000000010a0751d8 __95-[STTwitterAppOnly getResource:baseURLString:parameters:progressBlock:successBlock:errorBlock:]_block_invoke104 + 184
9 Tweets By Location 0x000000010a065a32 __158+[STHTTPRequest(STTwitter) twitterRequestWithURLString:stTwitterUploadProgressBlock:stTwitterDownloadProgressBlock:stTwitterSuccessBlock:stTwitterErrorBlock:]_block_invoke33 + 722
10 Tweets By Location 0x000000010a071538 -[STHTTPRequest connectionDidFinishLoading:] + 472
11 CFNetwork 0x00000001105212cc __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke + 69
12 CFNetwork 0x0000000110521270 -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 199
13 CFNetwork 0x00000001105213d7 -[NSURLConnectionInternal _withActiveConnectionAndDelegate:] + 48
14 CFNetwork 0x00000001103f25f7 ___ZN27URLConnectionClient_Classic26_delegate_didFinishLoadingEU13block_pointerFvvE_block_invoke + 107
15 CFNetwork 0x00000001104be871 ___ZN27URLConnectionClient_Classic18_withDelegateAsyncEPKcU13block_pointerFvP16_CFURLConnectionPK33CFURLConnectionClientCurrent_VMaxE_block_invoke_2 + 273
16 CFNetwork 0x00000001103ddb36 _ZN19RunloopBlockContext13_invoke_blockEPKvPv + 72
17 CoreFoundation 0x000000010ad0c714 CFArrayApplyFunction + 68
18 CFNetwork 0x00000001103dd9f7 _ZN19RunloopBlockContext7performEv + 133
19 CFNetwork 0x00000001103dd836 _ZN17MultiplexerSource7performEv + 256
20 CFNetwork 0x00000001103dd64c _ZN17MultiplexerSource8_performEPv + 72
21 CoreFoundation 0x000000010ad39ad1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
22 CoreFoundation 0x000000010ad2f99d __CFRunLoopDoSources0 + 269
23 CoreFoundation 0x000000010ad2efd4 __CFRunLoopRun + 868
24 CoreFoundation 0x000000010ad2ea06 CFRunLoopRunSpecific + 470
25 GraphicsServices 0x000000010cf2f9f0 GSEventRunModal + 161
26 UIKit 0x000000010b277550 UIApplicationMain + 1282
27 Tweets By Location 0x000000010a089e43 main + 115
28 libdyld.dylib 0x000000010cb78145 start + 1
29 ??? 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
答案 0 :(得分：1)
崩溃日志中的这一行：
2014-10-06 14:18:08.622 Tweets By Location[3612:174001] -[__NSCFArray length]: unrecognized selector sent to instance 0x7fa983d03510
表示您正在向数组发送length，但数组没有名为length的方法。
原因是这段代码：
NSString *tweetLocation = [[t valueForKey:@"geo"]valueForKey:@"coordinates"];
NSLog(@"Tweet Location: %@", tweetLocation);
if ([tweetLocation length] == 0) {
continue;
}
您假设geo.coordinates处的任何内容都是字符串，但服务器返回一个数组。
要修复它，请查看服务器应返回的规范，并调整代码以符合规范。如果服务器可能返回该字段的数组或字符串，则可以使用isKindOfClass:测试在运行时返回的数据。
答案 1 :(得分：1)
元素"coordinates"不是字符串。
根据文档，您正在遍历的对象是Tweet对象： https://dev.twitter.com/overview/api/tweets
此coordinates部分与此示例类似：
"coordinates":
[
-75.14310264,
40.05701649
]
您应该将coordinates解析为表示（经度，纬度）对的数组。
请注意，coordinates可能为空（与[NSNull null]相比），因此您也应该考虑到这一点。
答案 2 :(得分：0)
我弄清楚它崩溃的原因。我必须检查坐标JSON数组是否等于NSNull。
if ([tweetLocation isEqual:[NSNull null]]) {
continue;
}
else {
double lat = [[tweetLocation objectAtIndex:0]doubleValue];
double longitude = [[tweetLocation objectAtIndex:1]doubleValue];
locationCoord.latitude = lat;
locationCoord.longitude = longitude;
NSLog(@"Lat: %.8f, Long: %.8f", lat, longitude);
twitterName = [t valueForKeyPath:@"user.screen_name"];
NSLog(@"Twitter name: %@", twitterName);
tweetAnnotation.title = twitterName;
tweetAnnotation.coordinate = locationCoord;
[tweetLocationsArray addObject:tweetAnnotation];
}