Android TextView : "Do not concatenate text displayed with setText"

173
votes

I am setting text using setText() by following way.

prodNameView.setText("" + name);

prodOriginalPriceView.setText("" + String.format(getString(R.string.string_product_rate_with_ruppe_sign), "" + new BigDecimal(price).setScale(2, RoundingMode.UP)));

In that First one is simple use and Second one is setting text with formatting text.

Android Studio is so much interesting, I used Menu Analyze -> Code Cleanup and i got suggestion on above two lines like.

enter image description here

Do not concatenate text displayed with setText. Use resource string with placeholders. less... (Ctrl+F1)

When calling TextView#setText:

  • Never call Number#toString() to format numbers; it will not handle fraction separators and locale-specific digits properly. Consider using String#format with proper format specifications (%d or %f) instead.
  • Do not pass a string literal (e.g. "Hello") to display text. Hardcoded text can not be properly translated to other languages. Consider using Android resource strings instead.
  • Do not build messages by concatenating text chunks. Such messages can not be properly translated.

What I can do for this? Anyone can help explain what the thing is and what should I do?

11
androidconcatenationtextviewstring-concatenation
That means you should pass only a String into setText(). Ex: setText(name) in stead of setText("" + name). Because if you concatenate text, it will not be translated like you use Hardcoded text as the message notify – Mr Neo
But it will give NPE if name is NULL – Pratik Butani
check name is not NULL before using setText() function. – Mr Neo
You should not concat a String resource with some value, instead use placeholders in your string resource. So in your string.xml you do: <string name="string_product_rate_with_ruppe_sign">Something %1$d</string> And in your java code you do something like this: prodOriginalPriceView.setText(getString(R.string.string_product_rate_with_ruppe_sign), price); (you can do the formatting in the xml file: [developer.android.com/guide/topics/resources/… – CodeBreakers

11 Answers

349
votes

Resource has the get overloaded version of getString which takes a varargs of type Object: getString(int, java.lang.Object...). If you setup correctly your string in strings.xml, with the correct place holders, you can use this version to retrieve the formatted version of your final String. E.g. 

<string name="welcome_messages">Hello, %1$s! You have %2$d new messages.</string>

using getString(R.string.welcome_message, "Test", 0);

android will return a String with 

 "Hello Test! you have 0 new messages"

About setText("" + name);

Your first Example, prodNameView.setText("" + name); doesn't make any sense to me. The TextView is able to handle null values. If name is null, no text will be drawn.

47
votes

Don't get confused with %1$s and %2$d in the accepted answer.Here is a few extra information.

  • The format specifiers can be of the following syntax:

%[argument_index$]format_specifier

  1. The optional argument_index is specified as a number ending with a “$” after the “%” and selects the specified argument in the argument list. The first argument is referenced by "1$", the second by "2$", etc.
  2. The required format specifier is a character indicating how the argument should be formatted. The set of valid conversions for a given argument depends on the argument's data type.

Example

We will create the following formatted string where the gray parts are inserted programmatically.

Hello Test! you have 0 new messages

Your string resource:

< string name="welcome_messages">Hello, %1$s! You have %2$d new messages< /string >

Do the string substitution as given below:

getString(R.string.welcome_message, "Test", 0);

Note:

  • %1$s will be substituted by the string "Test"
  • %2$d will be substituted by the string "0"
19
votes

I ran into the same lint error message and solved it this way.

Initially my code was:

private void displayQuantity(int quantity) {
    TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
    quantityTextView.setText("" + quantity);
}

I got the following error 

Do not concatenate text displayed with setText. Use resource string with placeholders.

So, I added this to strings.xml

<string name="blank">%d</string>

Which is my initial "" + a placeholder for my number(quantity).

Note: My quantity variable was previously defined and is what I wanted to append to the string. My code as a result was

private void displayQuantity(int quantity) {
    TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
    quantityTextView.setText(getString(R.string.blank, quantity));
}

After this, my error went away. The behavior in the app did not change and my quantity continued to display as I wanted it to now without a lint error.

13
votes

Do not concatenate text inside your setText() method, Concatenate what ever you want in a String and put that String value inside your setText() method.

ex: correct way

int min = 120;
int sec = 200;
int hrs = 2;

String minutes = String.format("%02d", mins);
String seconds = String.format("%02d", secs);
String newTime = hrs+":"+minutes+":"+seconds;

text.setText(minutes);

Do not concatenate inside setText() like

text.setText(hrs+":"+String.format("%02d", mins)+":"+String.format("%02d", secs));
11
votes

You should check this thread and use a placeholder like his one (not tested)

<string name="string_product_rate_with_ruppe_sign">Price : %1$d</string>

String text = String.format(getString(R.string.string_product_rate_with_ruppe_sign),new BigDecimal(price).setScale(2, RoundingMode.UP));
prodOriginalPriceView.setText(text);
5
votes

the problem is because you are appending "" at the beginning of every string.

lint will scan arguments being passed to setText and will generate warnings, in your case following warning is relevant:

Do not build messages by concatenating text chunks. Such messages can not be properly translated.

as you are concatenating every string with "".

remove this concatenation as the arguments you are passing are already text. Also, you can use .toString() if at all required anywhere else instead of concatenating your string with ""

2
votes

Don't Mad, It's too Simple.

String firstname = firstname.getText().toString();
String result = "hi "+ firstname +" Welcome Here";
            mytextview.setText(result);
0
votes

If you don't need to support i18n, you can disable this lint check in Android Studio

File -> Settings -> Editor -> Inspections -> Android -> Lint -> TextView Internationalization(uncheck this)

0
votes

You can use this , it works for me

title.setText(MessageFormat.format("{0} {1}", itemList.get(position).getOppName(), itemList.get(position).getBatchNum()));
0
votes
prodNameView.setText("" + name); //this produce lint error

val nameStr="" + name;//workaround for quick warning fix require rebuild
prodNameView.setText(nameStr);
-1
votes

if it is textView you can use like that : myTextView.text = ("Hello World") in editText you can use myTextView.setText("Hello World")