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If you don't know how to write a fairly simple Java expression in Kotlin. Here is a simple trick, which is to write a piece of code in the Java file of AndroidStudio and paste it into the kt file and it will automatically convert to Kotlin.
Kotlin Advantages
- It is easier to express: this is one of its most important advantages. You can write much less code.
- It is more secure: Kotlin is empty-security, which means that it handles various null situations during our compilation period, avoiding execution exceptions. You can save a lot of time in debugging null pointer exceptions and solve bugs caused by null.
- It can extend functions: this means that even if we do not have permission to access the code in this class, we can extend more features of this class.
- It is functional: Kotlin is an object-oriented language. But like many other modern languages, it uses a lot of functional programming concepts, such as using lambda expressions to solve problems more easily. One of the great features is how Collections is handled. I'll introduce it later.
- It is highly interoperable: you can continue to use all the code and libraries written in Java, and even use a mixed programming language in Kotlin and Java in one project. One line of Java and one line of Kotlin.
OK, let's not say much, let's take a look at the main text of this article
Many times we need to determine whether the data input in EditText is empty. In Java, the following code is needed:
String mobile = ().toString();
if ((mobile)) {
showError("The mobile phone number cannot be empty");
return;
}
String password = ().toString();
if ((password)) {
showError("Password cannot be empty");
return;
}
...Now let's take a look at how the same thing is done elegantly with Kotlin:
// Write an extension methodfun (message: String): String? {
val text = ()
if (()) {
showError(message)
return null
}
return text
}
// Elegantly verbalval mobile = ("The mobile phone number cannot be empty") ?: return
val password = ("Password cannot be empty") ?: returnSummarize
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