if (String == null or String == "") doesn't activate [duplicate]

Question

I got this problem where I have three if statements and every one of them has IF String == null or String == "" and even the getText doesn't give any value, these doesn't activate.

 @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.action_two: final String hei = h.getText().toString(); final String wei = w.getText().toString(); String waist = wc.getText().toString(); if (hei == null || wei == null ){ final Animation animationFadeIn = AnimationUtils.loadAnimation(this, R.anim.fadein); checker.setText("Please, put your information in these spots!"); checker.startAnimation(animationFadeIn); } else if (waist == null){ AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle("Are you sure?"); builder.setMessage("If you let Waist circumference empty, we will ask it from you later.") .setCancelable(true) .setPositiveButton("OK", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { Intent i = new Intent(getApplicationContext(), number3.class); i.putExtra("height" , hei); i.putExtra("weight" , wei); startActivity(i); overridePendingTransition(R.anim.slide_in, R.anim.slide_out); } }); AlertDialog alert = builder.create(); alert.show(); } else{ Log.d("BMI Height" , String.valueOf(wei)); Log.d("BMI Weight" , String.valueOf(hei)); Intent i = new Intent(getApplicationContext(), healthcalculator3.class); i.putExtra("height" , hei); i.putExtra("WC" , waist); i.putExtra("weight" , wei); startActivity(i); overridePendingTransition(R.anim.slide_in, R.anim.slide_out); }

And even if all those (waist, wei, hei) are null or not value set, it only activates the last ELSE and the machine thinks that they have some data/value.

Instead of == use this

Rashin
– Rashin

2016-07-15 07:49:30 +00:00
Commented Jul 15, 2016 at 7:49 — Rashin
– Rashin, Commented Jul 15, 2016 at 7:49
set the hei=""; and check with hei.equalsIgnoreCase("")

Arjun saini
– Arjun saini

2016-07-15 07:49:50 +00:00
Commented Jul 15, 2016 at 7:49 — Arjun saini
– Arjun saini, Commented Jul 15, 2016 at 7:49
see my updated answer

Khizar Hayat
– Khizar Hayat

2016-07-15 07:50:37 +00:00
Commented Jul 15, 2016 at 7:50 — Khizar Hayat
– Khizar Hayat, Commented Jul 15, 2016 at 7:50

AMAN SINGH · Accepted Answer · 2016-07-15 07:52:08Z

1

You can also try this like

if (hei == null || wei == null || hei.equals("") || wei.equals("")){ // your body here }

answered Jul 15, 2016 at 7:52

AMAN SINGH

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Comments

Khizar Hayat · Accepted Answer · 2016-07-15 09:20:47Z

1

 Try this check if(!TextUtils.isEmpty(string){ //body here }

edited Jul 15, 2016 at 9:20

answered Jul 15, 2016 at 7:48

Khizar Hayat

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1 Comment

Joni Over a year ago

How can string be both null and equal to ""?

HormCodes · Accepted Answer · 2016-07-15 08:05:27Z

0

The best way to compare strings is use stringInstance.equals("what to compare"), so your code will be:

hei.equals("")

Also you can use length of string:

hei.length() > 0

edited Jul 15, 2016 at 8:05

answered Jul 15, 2016 at 7:57

HormCodes

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2 Comments

Tim Over a year ago

getLength doesn't exist

HormCodes Over a year ago

Ouch, error. Thank you. I edited my answer...

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