how to check the string array is empty or null android? [duplicate]

Question

This question already has answers here:

Check whether a string is not null and not empty (33 answers)

Closed 7 years ago.

I am new to java. Am unable to check for null. Could you enlighten me on this? I have string array which has no elements.

I tried this code

String[] k = new String[3];
if(k==null){
    System.out.println(k.length);
}

Answer 1

Very precisely

if(k!=null && k.length>0){
    System.out.println(k.length);
}else
    System.out.println("Array is not initialized or empty");

k!=null would check array is not null. And StringArray#length>0 would return it is not empty[you can also trim before check length which discard white spaces].

Some related popular question -

• What is null in java?
• Avoiding “!= null” statements in Java?

Answer 2

There's a key difference between a null array and an empty array. This is a test for null.

int arr[] = null;
if (arr == null) {
  System.out.println("array is null");
}

"Empty" here has no official meaning. I'm choosing to define empty as having 0 elements:

arr = new int[0];
if (arr.length == 0) {
  System.out.println("array is empty");
}

An alternative definition of "empty" is if all the elements are null:

Object arr[] = new Object[10];
boolean empty = true;
for (int i=0; i<arr.length; i++) {
  if (arr[i] != null) {
    empty = false;
    break;
  }
}

or

Object arr[] = new Object[10];
boolean empty = true;
for (Object ob : arr) {
  if (ob != null) {
    empty = false;
    break;
  }
}

Reference

Answer 3

if (myArray == null)

   System.Console.WriteLine("array is not initialized");

else if (myArray.Length < 1)

   System.Console.WriteLine("array is empty");

Answer 4

String k[] = new String[3];

if(k.length == 0 ){

System.out.println("Null");
}

it will display null if there is no item in array.

Answer 5

I think you can use this:

if(str != null && !str.isEmpty())

UPDATE

Better solution is this one:

TextUtils.isEmpty(str)