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

Question

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.

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?

Answer 1

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.

Answer 2

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"