类似的字符串比较失败

Question

I am trying the following code in Android Studio. When Debugging, I find out that even when Value of variable B is "(" my if statement does not execute and hovering over it, it shows it is false (please refer to image). The value of ScreenText in this case is "6(".

Any help is appreciated.

.

Answer 1

You should compare strings with the .equals() method. In this case, and to prevent a null pointer exception in case that your B variable is null, you should do so like this:

if("(".equals(B)) {
...
}

Answer 2

The == operator is used for reference comparison, to check whether two object have the same reference.

You want to compare two String s, use the boolean equals(String) method.

if( "(".equals(B)) {
// your logic
}

Here comparing B with "(" constant does not require you to make null checks.

Answer 3

I think a more generic way to compare strings in Android is:

TextUtils.equals(B, "(");

And by the way, in your code

String.valueOf(c).toString();

toString() is redundant.

Answer 4

If you want to compare the value or contents of two strings then use .equals() .

if(string.equals("(")){
    //Enter your code
}

But if you want to check that two object points to same reference then use ==