CODEWITHSUNDEEP
javaandroid
user3694470
user3694470

Reputation: 143

Null checking not working

sorry if this is a low quality question, but still is a question :) here im using a simple in the eyes condition for checking EditText's null Being,

public String theuser=null;
public String thepass=null;

EditText  u=(EditText)findViewById(R.id.inputuser);
this.theuser = u.getText().toString();
EditText p =(EditText)findViewById(R.id.inputpassword);
this.thepass = p.getText().toString();

if ((theuser.equals(null))||(thepass.equals(null))){ 
    Toast.makeText(this,"Username and Password Cant Be Empty!",     
    Toast.LENGTH_SHORT).show();   
}else{
    Log.i("lifemate","did you click me ?!"+theuser+"  "+thepass);
    BusProvider.getInstance().post(SendRequestInfo());
}

but the null check seems to be not working ! i tried .equals(null) and .equals("") too still not working! do guys know why is that ?!

Upvotes: 1

Views: 143

Answers (6)

GovindRathod
GovindRathod

Reputation: 887

For checking the null in string android provide very good class over there

you just pass your string in

//check while for the null string. 
if(TextUtils.isEmpty("YOUR_STRING")){
 //perform operation. 
}

It will automatically handle NULL as well as EMPTY string.

Upvotes: 0

weston
weston

Reputation: 54801

Equals contract states that:

For any non-null reference value x, x.equals(null) should return false.

But when x is null this would cause a NullPointerException because you are trying to access a method of a null object.

In short use x == null rather than x.equals(null).

But in your case

You are testing the text value from a TextView. I would not expect this to be null, particulary as you call toString() on a CharSequence. So this will be just empty if anything, i.e. you can do this:

if ("".equals(theuser) || "".equals(thepass)) {

Upvotes: 0

Jens
Jens

Reputation: 69460

that if ((theuser.equals(null))||(thepass.equals(null))){

must be if ((theuser.equals(""))||(thepassequals(""))){

because getText() returns an empty string if there is no input. It not return null.

Upvotes: 2

Macrosoft-Dev
Macrosoft-Dev

Reputation: 2185

replace 

if ((theuser.equals(null))||(thepass.equals(null)))

with 

if (theuser==null||thepass==null)

Upvotes: 0

marshallino16
marshallino16

Reputation: 2671

equals null is not applicable for the reference of your String object.

You need to use (mystring != null) to test the nullability.

Upvotes: 0

peter.petrov
peter.petrov

Reputation: 39477

Comparison to null should be done using the == operator.

So use if (theuser==null || thepass == null).

Upvotes: 3

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