editText field is required before moving on to another Activity

Question

I have validation for editText. If the editText field is empty it should fail validation and stop the user moving on to another Activity, as a value is required. How to do it? I know this is a basic question, but I can't figure out how to do this.

My code:

btninsert = (Button)findViewById(R.id.btn_insert);
btninsert.setOnClickListener( new View.OnClickListener() {
    public void onClick(View v) {
        insertValues();
        EditText userName = (EditText) findViewById(R.id.editText1);

        if( userName.getText().toString().length() == 0 )
            userName.setError( "First name is required!" );

        Intent i = new Intent(getApplicationContext(), Login.class);
        startActivity(i);
    }
});

When this Button is clicked the user is redirect to next screen, but I need that if validation fails they stay on the current Activity, and only when validation is successful (i.e. a value has been entered) they go to the next Activity.

Answer 1

It's easy...check if your EditText is empty as in below example below.

if( TextUtils.isEmpty(userName.getText())){
   /**
    *   You can Toast a message here that the Username is Empty    
    **/
    
   userName.setError( "First name is required!" );

}else{
   Intent i = new Intent(getApplicationContext(), Login.class);
   startActivity(i);
}

Here is a Kotlin version:

userName.takeIf { it.isEmpty() }?.let {
  userName.error = "First name is required!"
} ?: run {
   startActivity(Intent(applicationContext, this))
}