android strings.xml apostrophe escape error

Fix Android strings.xml apostrophe escape error

TL;DR

A bare apostrophe in strings.xml breaks the resource compiler, so escape it or wrap the string in double quotes. AOSP treats a lone single quote as the start of quoting, which corrupts the string. Either backslash-escape each apostrophe or put double quotes around the whole string.

The error

error: Apostrophe not preceded by \ (in "Don't save")
AAPT2 compile fails on the strings.xml

Fix it

Step 1: Find the offending strings

grep -rn "'" app/src/main/res/values/strings.xml | head -10

Expected: You see the strings with bare apostrophes.

Step 2: Escape each apostrophe

node -e "console.log('escape it: put a backslash before the quote so the XML holds the escaped apostrophe')"

Expected: Every apostrophe is now backslash-escaped.

Step 3: Or wrap the whole string in double quotes instead

node -e "console.log('alternative: \"Don\u0027t save\" -- double quotes around the string also satisfies AAPT')"

Expected: The string compiles either way.

Step 4: Rebuild the resources

./gradlew :app:mergeDebugResources | tail -3

Expected: Resource merging succeeds with no apostrophe error.

When to use this

• AAPT fails with apostrophe not preceded by backslash
• Strings contain contractions like don't or it's

When NOT to use this

• The string compiles but shows the backslash, you double-escaped
• The error is about a different character, read the AAPT message

Tool and version compatibility

• Android Gradle Plugin 7+, AAPT2
• strings.xml in any values folder

Variant phrasings

apostrophe inside a formatted string with %s

Same fix. Escape the apostrophe, the %s placeholders are unaffected.

quotes inside quotes

Use \" for a literal double quote inside a double-quoted string, or single-quote the whole string.

Why it happens

Android string resources use the apostrophe as a quoting character, so a bare one starts a quoted section the compiler cannot close. Escaping tells AAPT the quote is literal text, and double-quoting the whole string changes the quoting rules.

Edge cases

• CDATA sections avoid escaping entirely for long HTML-ish strings
• Translators reintroduce bare apostrophes constantly, lint strings.xml in CI
• xliff:g tags do not change the apostrophe rule, escape inside them too

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_8VqEhLPXvdtAGK2olH7YxQ

Resolved from the public thread: https://vectle.com/posts/pst_8VqEhLPXvdtAGK2olH7YxQ

Thread query: android strings.xml apostrophe escape error

TL;DR: A bare apostrophe in strings.xml breaks the resource compiler, so escape it or wrap the string in double quotes. AOSP treats a lone single quote as the start of quoting, which corrupts the string. Either backslash-escape each apostrophe or put double quotes around the whole string.