java - All of a sudden, I cannot change any strings in Android Studio -

i using google+ api , trying add chat application (not run chat using google). chat part easy, yet can't change strings add backslash before apostrophe of sudden. plus, has added <resources xmlns:ns1="urn:oasis:names:tc:xliff:document:1.2">, , not know why there nor means.

my strings.xml file (not entire file):

<!-- top of file --> <?xml version="1.0" encoding="utf-8"?> <resources xmlns:ns1="urn:oasis:names:tc:xliff:document:1.2">   <string name="common_android_wear_notification_needs_update_text"><ns1:g id="app_name">%1$s</ns1:g> requires update android wear app.</string> <string name="common_android_wear_update_text"><ns1:g id="app_name">%1$s</ns1:g> won\'t run unless update android wear app.</string> <string msgid="6006316683626838685" name="common_android_wear_update_title">update android wear</string> <string name="common_google_play_services_api_unavailable_text"><ns1:g id="app_name">%1$s</ns1:g> requires 1 or more google play services not available. please contact developer assistance.</string> <string msgid="2523291102206661146" name="common_google_play_services_enable_button">enable google play services</string> <string msgid="227660514972886228" name="common_google_play_services_enable_text"><ns1:g id="app_name">%1$s</ns1:g> won\'t work unless enable google play services.</string> <string msgid="5122002158466380389" name="common_google_play_services_enable_title">enable google play services</string> <string name="common_google_play_services_error_notification_requested_by_msg">requested <ns1:g id="app_name">%1$s</ns1:g></string> <string msgid="7153882981874058840" name="common_google_play_services_install_button">get google play services</string> <string msgid="2122112764540849864" name="common_google_play_services_install_text_phone"><ns1:g id="app_name">%1$s</ns1:g> won\'t run without google play services, missing phone.</string> <string msgid="7351599665250191022" name="common_google_play_services_install_text_tablet"><ns1:g id="app_name">%1$s</ns1:g> won\'t run without google play services, missing tablet.</string> <string msgid="7215213145546190223" name="common_google_play_services_install_title">get google play services</string> <string name="common_google_play_services_invalid_account_text">the specified account not exist on device. please choose different account.</string> <string name="common_google_play_services_invalid_account_title">invalid account</string> <string name="common_google_play_services_needs_enabling_title">an application requires google play services enabled.</string> <string name="common_google_play_services_network_error_text">a data connection required connect google play services.</string> <string name="common_google_play_services_network_error_title">network error</string> <string name="common_google_play_services_notification_needs_update_title">an application requires update google play services.</string> <string name="common_google_play_services_notification_ticker">google play services error</string> <string name="common_google_play_services_sign_in_failed_text">error signing in specified account. please choose different account.</string> <string name="common_google_play_services_sign_in_failed_title">sign in failed</string> <string name="common_google_play_services_unknown_issue">unknown issue google play services.</string> <string name="common_google_play_services_unsupported_text"><ns1:g id="app_name">%1$s</ns1:g> relies on google play services, not supported device. contact manufacturer assistance.</string> <string name="common_google_play_services_unsupported_title">google play services</string> <string msgid="6556509956452265614" name="common_google_play_services_update_button">update</string> <string msgid="9053896323427875356" name="common_google_play_services_update_text"><ns1:g id="app_name">%1$s</ns1:g> won\'t run unless update google play services.</string> <string msgid="6006316683626838685" name="common_google_play_services_update_title">update google play services</string> <string name="common_google_play_services_updating_text"><ns1:g id="app_name">%1$s</ns1:g> won\'t run without google play services, updating.</string> <string name="common_google_play_services_updating_title">google play services updating</string> <string name="common_open_on_phone">open on phone</string> <string name="common_signin_button_text">sign in</string> <string name="common_signin_button_text_long">sign in google</string> <string name="disk_cache_description">on ice cream sandwich , above, disk cache automatically used subsequent requests same url not re-download image.\n\nto enable functionality on pre-ics use standalone http client caching such okhttp. </string> <string name="easter_egg">i easter egg!</string> <string name="edit">edit</string> <string name="email">email</string> <string name="err_fields_empty">please fill fields.</string> <string name="err_login">error occurred while login:</string> <string name="err_singup">error occurred while signup:</string> <string name="err_users">error occurred while finding users:</string> <string name="error_a">error activity</string> <string name="error_b">unable launch specified activity or link page. check later.</string> <string name="error_field_required">this field required</string> <string name="error_incorrect_password">this password incorrect</string> <string name="error_invalid_email">this email address invalid</string> <string name="error_invalid_password">this password short</string> <string name="fetch_content_base">fetching content. please wait.</string> <string name="forgot_my_pwd">i can't remember password!</string> 

the forgot_my_pwd string has apostrophe , have tried add backslash, whenever build, compile, or clean, delete changes , error:(307) apostrophe not preceded \ (in can't remember password!). barely happened while adding couple strings, , don't think should change anything. appreciated have run out of clues on how solve this. thanks!

i have posted answer viewers experiencing same problem. of these steps explained in comments main post, here steps rewritten:

first, check see if strings.xml or values.xml file viewing not system one. tell if system one, tab file light yellow color, shown below.

if equivalent image shown, build file, , cannot edited.

to navigate editable file, make sure view on file tree set 'android' here:

now, navigate file circled in file browser shown in following image:

once have navigated file, should able change values of string desire.