Kotlin Null Safety

Null check in kotlin

if(a != null)  {
//do something
}

Kotlin Null Safety

// Variable types in Kotlin don't allow the assignment of null. 
// Declare a nullable varible by adding ? at the end of its type.
var neverNull: String = "This can't be null"            
neverNull = null                                        // Error
var nullable: String? = "You can keep a null here"      
nullable = null                                         // Ok
var inferredNonNull = "The compiler assumes non-null"   
inferredNonNull = null                                  // Error
fun strLength(notNull: String): Int {                   
    return notNull.length
}
strLength(neverNull)                                    // Ok
strLength(nullable)                                     // Error

Source: play.kotlinlang.org

Similar codes

1 vote158 views1 answer
Close dialog android
Kotlin
3 votes187 views1 answer
Picaso ftp files android
Kotlin
3 votes216 views2 answers
Kotlin power
Kotlin
0 vote222 views1 answer
Kotlin labels
Kotlin
1 vote301 views4 answers
Regex find emails
Kotlin
2 votes143 views1 answer
Kotlin download file from url
Kotlin
4 votes305 views2 answers
How to set layout params in android programmatically kotlin
Kotlin
1 vote199 views1 answer
Any in kotlin
Kotlin
1 vote197 views1 answer
Check if network is metered android
Kotlin
0 vote215 views1 answer
Kotlin for loop with float
Kotlin