if (text.equals("") Crashes

Question

I have a textfield on my view, and when the text changes on the textfield i have a if statement, so when a certain keyword is in the textview, some code will run. Here is my code for the if statement:

 if (text1.equals("rotate")) {


                red.setRotation(red.getRotation() + 5);

                blue.setRotation(blue.getRotation() + 5);


            }

but when text1 equals 'rotate' and its running this code, the app will crash.

Here is the log cat:

Always post your logcat in code in question. Never add it as picture. — Damian Kozlak, Nov 23 '15 at 18:26
[What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — PPartisan, Nov 23 '15 at 18:39

score 5 · Answer 1 · answered Nov 23 '15 at 18:21

5

The reason for that is text1 is null and you are trying to call a method on null reference.

Either you forgot to initialize it or no value assigned yet.

If you already have the initialization and if there are chances to get a null value, you need to have a guard condition for that.

 if (text1 !=null && text1.equals("rotate")) {

This first checks for null and then invoke the method.

answered Nov 23 '15 at 18:21

Suresh Atta

118,038
37
189
297

1

Simply do "rotate".equals(text1) that should take care on NPE. you don't need to check for null. – StackFlowed Nov 23 '15 at 18:24
1

@StackFlowed [I know that, but cared for OP's beginner level :)](http://stackoverflow.com/questions/18611050/what-are-the-benefits-of-string-equalsotherstring/18611083#18611083) – Suresh Atta Nov 23 '15 at 18:25
Agreed. what about Apache StringUtils.isNotBlank(text1) ? – StackFlowed Nov 23 '15 at 18:27
@StackFlowed Let OP learn the core things :) Then he optimize his codes with them. – Suresh Atta Nov 23 '15 at 18:28
Even if i use this code, the app still crashes. With the same log – fafafa Nov 23 '15 at 18:42

score 1 · Answer 2 · answered Nov 23 '15 at 18:22

1

It appears like text1 is not initialized. In you method, initialize text1. Here's an example of how to:

text1   = (EditText)findViewById(R.id.text1);

If it is initialized and can have null, then guard it.

 if ("rotate".equals(text1)) {

answered Nov 23 '15 at 18:22

Aragorn

4,534
3
25
35

score 0 · Answer 3 · answered Nov 23 '15 at 18:29

First: Initialise text1

If it is a TextView then

text1 = (TextView) findViewById(R.id.textview_id);

If it is a EditText then

text1 = (EditText) findViewById(R.id.editText_id);

Second: Compare it like this:

if (text1.getText().toString().equalsIgnoreCase("rotate")) {
   red.setRotation(red.getRotation() + 5);
   blue.setRotation(blue.getRotation() + 5);
 }

score 0 · Answer 4 · answered Nov 23 '15 at 18:49

0

First of all you need to initialise the text1 object. From the log it is clear that the text1 object is null.

You can then compare the string using:

if (text1 && "rotate".equals(text1.getText().toString()))
{
}

answered Nov 23 '15 at 18:49

Midhun MP

97,760
30
152
197

if (text.equals("") Crashes

4 Answers4