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

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.

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.

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"