String comparison on Android Data Binding

Question

I'm trying to make a string comparison with android XML data binding, but I'm not having the right results.

Evaluating my expression in code, I try notice.action == "continue" and this is false. And in data binding, this is false too, of course.

android:textColor='@{ notice.action == "continue" ? @color/enabledPurple : @color/disabledGray}'

It only gets true when I do notice.action.equals("continue") by code. This is the intended behavior. My problem is that I can't accomplish this with data binding expressions, because it won't run methods like equals. What can I do to replace the comparison expression with another one that works?

I'm using this guide.

Edit: I was wrong, methods are allowed in XML. Did it this way:

android:textColor='@{ notice.action.equals("continue") ? @color/enabledPurple : @color/disabledGray}'

Why do you say that it won't run a method like .equals()? Methods are supported in data binding expressions. — George Mount, Mar 14 '16 at 14:03
Re-reading the docs, I found it. I guess I past over it. Thank you for pointing this, I will try in my code! — Ricardo Melo, Mar 14 '16 at 15:15
Could you please share the code for using equals() in databinding — anoopg87, Jul 14 '16 at 07:21
Of course. It's like this @anoopg87. "android:textColor='@{ notice.action.equals("continue") ? @color/enabledPurple : @color/disabledGray}'" — Ricardo Melo, Jul 14 '16 at 12:28

score 60 · Accepted Answer · edited Apr 26 '19 at 08:07

It can be do in two way :-

1. First way inside xml :-

    android:textColor="@{notice.action.equals(`continue`) ? @color/enabledPurple : @color/disabledGray }"

2. Second way (programatically) Inside xml :-

app:setColor="@{notice.action}" 
inside activity or custom class : -    
    @BindingAdapter("setColor")
        public static void setTextColor(TextView textView, String s) {

             Context context = textView.getContext();

        textView.setTextColor(s.equals("continue") ? context.getResources().getColor(R.color.enabledPurple) : context.getResources().getColor(R.color.disabledGray));
        }

score 8 · Answer 2 · answered Jul 18 '18 at 12:23

8

There is no need to import the String class into your layout file.

To check whether two strings have equal value or not equals() method should be used.

= is used to check the whether the two strings refer to the same reference object or not.

Solution:

android:textColor="@{notice.action.equals(`continue`) ? @color/enabledPurple : @color/disabledGray }"

answered Jul 18 '18 at 12:23

Bhupendra Joshi

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This may throw java.lang.reflect.InvocationTargetException: "String has already been defined as java.lang.String but trying to re-define as String" – esQmo_ Mar 04 '21 at 11:03

score 5 · Answer 3 · answered Oct 16 '20 at 02:39

5

'continue' is char type, so it should be changed to String to compare with notice.action.

android:textColor="@{notice.action.equals(String.valueOf(`continue`)) ? @color/enabledPurple : @color/disabledGray }"

answered Oct 16 '20 at 02:39

Jagpaw

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score 3 · Answer 4 · answered Nov 08 '16 at 09:41

3

Try to add in xml

<data> <import type="String"/> </data> It may help to resolve .equals()

answered Nov 08 '16 at 09:41

Chickin Nick

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String comparison on Android Data Binding

4 Answers4