Handle fp enrollment errors more gracefully

- When finger can't be analyzed for enrollment
(FINGERPRINT_ERROR_UNABLE_TO_PROCESS), tell the user
to try again or use a different finger.
- When timeout is reached (FINGERPRINT_ERROR_TIMEOUT),
stop enrollment and ask the user to try again.

Fixes bug 23546104
Fixes bug 22708384

Change-Id: I879874b53dd0d928093fab1c92d0d4d68d73be28

src/com/android/settings/fingerprint/FingerprintSettings.java

@@ -70,8 +70,9 @@ import java.util.List;
  * Settings screen for fingerprints
  */
 public class FingerprintSettings extends SubSettings {
+
     /**
-     * Used by the FP settings wizard to indicate the wizard is
+     * Used by the choose fingerprint wizard to indicate the wizard is
      * finished, and each activity in the wizard should finish.
      * <p>
      * Previously, each activity in the wizard would finish itself after
@@ -79,7 +80,21 @@ public class FingerprintSettings extends SubSettings {
      * behavior. So, now an activity does not finish itself until it gets this
      * result.
      */
-    static final int RESULT_FINISHED = RESULT_FIRST_USER;
+    protected static final int RESULT_FINISHED = RESULT_FIRST_USER;
+
+    /**
+     * Used by the enrolling screen during setup wizard to skip over setting up fingerprint, which
+     * will be useful if the user accidentally entered this flow.
+     */
+    protected static final int RESULT_SKIP = RESULT_FIRST_USER + 1;
+
+    /**
+     * Like {@link #RESULT_FINISHED} except this one indicates enrollment failed because the
+     * device was left idle. This is used to clear the credential token to require the user to
+     * re-enter their pin/pattern/password before continuing.
+     */
+    protected static final int RESULT_TIMEOUT = RESULT_FIRST_USER + 2;
+
     private static final long LOCKOUT_DURATION = 30000; // time we have to wait for fp to reset, ms
 
     @Override
@@ -441,6 +456,12 @@ public class FingerprintSettings extends SubSettings {
                                 ChooseLockSettingsHelper.EXTRA_KEY_CHALLENGE_TOKEN);
                     }
                 }
+            } else if (requestCode == ADD_FINGERPRINT_REQUEST) {
+                if (resultCode == RESULT_TIMEOUT) {
+                    Activity activity = getActivity();
+                    activity.setResult(RESULT_TIMEOUT);
+                    activity.finish();
+                }
             }
 
             if (mToken == null) {