在我的视图控制器中，我订阅了UIKeyboardWillShowNotification：
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
所以在我的keyboardWillShow:方法中，我能够从通知中检索有关键盘的一些信息。但我想要的是获得引入键盘的实际文本字段的引用。我在谷歌找不到怎么做，我怀疑这可能是不可能的，但有人可能知道。如果确实不可能，那么我想知道是否有可能以相反的方式 - 通过引用文本字段来获取有关键盘的信息。谢谢
答案 0 :(得分：5)
让我强调 @iphonic评论是正确的方法。
您应该使用
UITextField委托函数textFieldShouldBeginEditing:
任何不足之处都是kludge：UIKeyboardWillShowNotification假设软件键盘会出现，这是一个非常危险的假设，在各种情况下可能会失败，从但不限于蓝牙键盘。 在模拟器中尝试cmd-K。
以上是上述kludge，灵感来自Get the current first responder without using a private API
func keyboardWillShow() {
let firstResponder = self.findFirstResponder(inView: self.view)
println("keyboardWillShow for \(firstResponder)")
}
func findFirstResponder(inView view: UIView) -> UIView? {
for subView in view.subviews as! [UIView] {
if subView.isFirstResponder() {
return subView
}
if let recursiveSubView = self.findFirstResponder(inView: subView) {
return recursiveSubView
}
}
return nil
}
答案 1 :(得分：5)
有一种手动方式
MainActivity夫特
if ([firstName isFirstResponder]) {
// caused due to firstName
} else if ([lastName isFirstResponder]) {
// caused due to lastName
}
答案 2 :(得分：2)
通过开始编辑Undefined symbols for architecture i386:
"_deflate", referenced from:
+[GAICompressionUtil gai_dataByCompressingBytes:length:compressionLevel:mode:] in libGoogleAnalyticsServices.a(GAICompressionUtil.o)
"_deflateEnd", referenced from:
+[GAICompressionUtil gai_dataByCompressingBytes:length:compressionLevel:mode:] in libGoogleAnalyticsServices.a(GAICompressionUtil.o)
"_deflateInit2_", referenced from:
+[GAICompressionUtil gai_dataByCompressingBytes:length:compressionLevel:mode:] in libGoogleAnalyticsServices.a(GAICompressionUtil.o)
"_inflate", referenced from:
+[GAICompressionUtil gai_dataByInflatingBytes:length:isRawData:] in libGoogleAnalyticsServices.a(GAICompressionUtil.o)
"_inflateEnd", referenced from:
+[GAICompressionUtil gai_dataByInflatingBytes:length:isRawData:] in libGoogleAnalyticsServices.a(GAICompressionUtil.o)
"_inflateInit2_", referenced from:
+[GAICompressionUtil gai_dataByInflatingBytes:length:isRawData:] in libGoogleAnalyticsServices.a(GAICompressionUtil.o)
"_sqlite3_bind_blob", referenced from:
-[TAGDataLayerPersistentStoreImpl writeEntriesToDatabase:expireTime:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_bind_double", referenced from:
-[GAIAnalyticsPropertiesStore bindRecord:toUpsertStatement:] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
"_sqlite3_bind_int", referenced from:
-[TAGDataLayerPersistentStoreImpl deleteEntries:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_bind_int64", referenced from:
-[TAGDataLayerPersistentStoreImpl writeEntriesToDatabase:expireTime:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl peekEntryIds:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl deleteEntriesOlderThan:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[GAIAnalyticsPropertiesStore bindRecord:toUpsertStatement:] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
"_sqlite3_bind_text", referenced from:
-[GAISqlStore tableExists:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl clearKeysWithPrefixSingleThreaded:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl writeEntriesToDatabase:expireTime:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[GAIAnalyticsPropertiesStore bindRecord:toUpsertStatement:] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
-[GAIAnalyticsPropertiesStore selectStmtWithTrackingId:] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
"_sqlite3_close", referenced from:
-[GAISqlStore closeDatabase] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl closeDatabase] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_column_blob", referenced from:
-[TAGDataLayerPersistentStoreImpl loadSerialized] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_column_bytes", referenced from:
-[TAGDataLayerPersistentStoreImpl loadSerialized] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_column_count", referenced from:
-[GAISqlStore openAndValidateDatabase] in libGoogleAnalyticsServices.a(GAISqlStore.o)
"_sqlite3_column_double", referenced from:
-[GAIAnalyticsPropertiesStore propertyRecordForTrackingId:] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
"_sqlite3_column_int", referenced from:
-[GAISqlStore rowCountForTableWithName:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
"_sqlite3_column_int64", referenced from:
-[TAGDataLayerPersistentStoreImpl peekEntryIds:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl numStoredEntries] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[GAIAnalyticsPropertiesStore propertyRecordForTrackingId:] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
"_sqlite3_column_text", referenced from:
-[GAISqlStore openAndValidateDatabase] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl loadSerialized] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[GAIAnalyticsPropertiesStore hasValidPropertyColumns] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
-[GAIAnalyticsPropertiesStore propertyRecordForTrackingId:] in libGoogleAnalyticsServices.a(GAIAnalyticsPropertiesStore.o)
"_sqlite3_errcode", referenced from:
-[TAGDataLayerPersistentStoreImpl prepareSql:description:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_errmsg", referenced from:
-[GAISqlStore errorMessage] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl clearKeysWithPrefixSingleThreaded:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl writeEntriesToDatabase:expireTime:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl deleteEntries:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl numStoredEntries] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl deleteEntriesOlderThan:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl tablePresent:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
...
"_sqlite3_finalize", referenced from:
-[GAISqlStore removeStatementForQuery:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore finalizeAndClearStatements] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore openAndValidateDatabase] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore prepareSql:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore executeSql:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl clearKeysWithPrefixSingleThreaded:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl deleteEntries:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
...
"_sqlite3_open", referenced from:
-[TAGDataLayerPersistentStoreImpl openDatabaseAndInitStatements] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_open_v2", referenced from:
-[GAISqlStore openAndValidateDatabase] in libGoogleAnalyticsServices.a(GAISqlStore.o)
"_sqlite3_prepare_v2", referenced from:
-[GAISqlStore prepareSql:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl prepareSql:description:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
"_sqlite3_reset", referenced from:
-[GAISqlStore rowCountForTableWithName:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore tableExists:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore dropTableWithName:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl loadSerialized] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl writeEntriesToDatabase:expireTime:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl peekEntryIds:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl numStoredEntries] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
...
"_sqlite3_step", referenced from:
-[GAISqlStore rowCountForTableWithName:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore openAndValidateDatabase] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore tableExists:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore dropTableWithName:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[GAISqlStore executeSql:] in libGoogleAnalyticsServices.a(GAISqlStore.o)
-[TAGDataLayerPersistentStoreImpl clearKeysWithPrefixSingleThreaded:] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
-[TAGDataLayerPersistentStoreImpl loadSerialized] in libGoogleAnalyticsServices.a(TAGDataLayerPersistentStoreImpl.o)
...
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)
和UITextField的通知，有更好的方法可以做到这一点：
UITextView
和
UITextFieldTextDidBeginEditingNotification
UITextViewTextDidBeginEditingNotification答案 3 :(得分：1)
最简单（也是几乎唯一）的方法也是最好的方法（如@iphonic所述）
实施
UITextFieldDelegate委托方法textFieldShouldBeginEditing:textField
在任何其他事件之前（包括所有键盘通知），该方法将被称为
存储在确定哪个字段触发此事件时要引用的
UITextField引用。
我还建议您执行以下操作：如果要确定是哪个键盘触发了当前的键盘外观，请内部使用此委托方法简单地注册以接收键盘通知。
- (BOOL)textFieldShouldBeginEditing:(UITextView *)textView {
[NSNotificationCenter.defaultCenter addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
return YES;
}
这样，您可以确定在调用keyboardWillShow:时，它实际上是从此特定文本字段触发的。
当然，要确保正确跟踪文本字段，请在文本字段停止编辑时停止收听。
- (void)textFieldDidEndEditing:(UITextView *)textView {
[NSNotificationCenter.defaultCenter removeObserver:self name:UIKeyboardWillShowNotification object:nil];
}