Fix inoperative "Forgot pattern" button when face unlock enabled

This fixes a bug where the forgot pattern button wasn't working because
the logic for face unlock was interfering with determining the proper
backup to use.

The fix:
- adds a new state to SecurityMode so we have an initial condition
we can check for.
- passes the current mode to SecurityModel.getBackupSecurityMode() so
it relies on the current state.
- prevents face unlock from invoking callbacks that change state
once we're no longer showing face unlock.

Fixes bug 7346989

Change-Id: I4e64515efbbad712f11c820e690b458f352bf46c

Author: Jim Miller

policy/src/com/android/internal/policy/impl/keyguard/KeyguardHostView.java

@@ -79,7 +79,7 @@ public class KeyguardHostView extends KeyguardViewBase {
     private boolean mEnableMenuKey;
     private boolean mIsVerifyUnlockOnly;
     private boolean mEnableFallback; // TODO: This should get the value from KeyguardPatternView
-    private SecurityMode mCurrentSecuritySelection = SecurityMode.None;
+    private SecurityMode mCurrentSecuritySelection = SecurityMode.Invalid;
 
     protected Runnable mLaunchRunnable;
 
@@ -433,7 +433,8 @@ void showPrimarySecurityScreen(boolean turningOff) {
      */
     private void showBackupSecurityScreen() {
         if (DEBUG) Log.d(TAG, "showBackupSecurity()");
-        showSecurityScreen(mSecurityModel.getBackupSecurityMode());
+        SecurityMode backup = mSecurityModel.getBackupSecurityMode(mCurrentSecuritySelection);
+        showSecurityScreen(backup);
     }
 
     public boolean showNextSecurityScreenIfPresent() {
@@ -543,6 +544,45 @@ public void run() {
 
     private KeyguardStatusViewManager mKeyguardStatusViewManager;
 
+    // Used to ignore callbacks from methods that are no longer current (e.g. face unlock).
+    // This avoids unwanted asynchronous events from messing with the state.
+    private KeyguardSecurityCallback mNullCallback = new KeyguardSecurityCallback() {
+
+        @Override
+        public void userActivity(long timeout) {
+        }
+
+        @Override
+        public void showBackupSecurity() {
+        }
+
+        @Override
+        public void setOnDismissRunnable(Runnable runnable) {
+        }
+
+        @Override
+        public void reportSuccessfulUnlockAttempt() {
+        }
+
+        @Override
+        public void reportFailedUnlockAttempt() {
+        }
+
+        @Override
+        public boolean isVerifyUnlockOnly() {
+            return false;
+        }
+
+        @Override
+        public int getFailedAttempts() {
+            return 0;
+        }
+
+        @Override
+        public void dismiss(boolean securityVerified) {
+        }
+    };
+
     @Override
     public void reset() {
         mIsVerifyUnlockOnly = false;
@@ -568,9 +608,10 @@ private KeyguardSecurityView getSecurityView(SecurityMode securityMode) {
             }
         }
         boolean simPukFullScreen = getResources().getBoolean(R.bool.kg_sim_puk_account_full_screen);
-        if (view == null) {
+        int layoutId = getLayoutIdFor(securityMode);
+        if (view == null && layoutId != 0) {
             final LayoutInflater inflater = LayoutInflater.from(mContext);
-            View v = inflater.inflate(getLayoutIdFor(securityMode), this, false);
+            View v = inflater.inflate(layoutId, this, false);
             mSecurityViewContainer.addView(v);
             updateSecurityView(v);
 
@@ -617,8 +658,12 @@ private void showSecurityScreen(SecurityMode securityMode) {
         KeyguardSecurityView newView = getSecurityView(securityMode);
 
         // Emulate Activity life cycle
-        oldView.onPause();
+        if (oldView != null) {
+            oldView.onPause();
+            oldView.setKeyguardCallback(mNullCallback); // ignore requests from old view
+        }
         newView.onResume();
+        newView.setKeyguardCallback(mCallback);
 
         final boolean needsInput = newView.needsInput();
         if (mViewMediatorCallback != null) {
@@ -749,7 +794,7 @@ private int getLayoutIdFor(SecurityMode securityMode) {
             case SimPin: return R.layout.keyguard_sim_pin_view;
             case SimPuk: return R.layout.keyguard_sim_puk_view;
             default:
-                throw new RuntimeException("No layout for securityMode " + securityMode);
+                return 0;
         }
     }
 

policy/src/com/android/internal/policy/impl/keyguard/KeyguardSecurityModel.java

@@ -28,6 +28,7 @@ public class KeyguardSecurityModel {
      * @see com.android.internal.policy.impl.LockPatternKeyguardView#getUnlockMode()
      */
     enum SecurityMode {
+        Invalid, // NULL state
         None, // No security enabled
         Pattern, // Unlock by drawing a pattern.
         Password, // Unlock by entering a password or PIN
@@ -53,7 +54,7 @@ void setLockPatternUtils(LockPatternUtils utils) {
      * Returns true if biometric unlock is installed and selected.  If this returns false there is
      * no need to even construct the biometric unlock.
      */
-    private boolean isBiometricUnlockEnabled() {
+    boolean isBiometricUnlockEnabled() {
         return mLockPatternUtils.usingBiometricWeak()
                 && mLockPatternUtils.isBiometricWeakInstalled();
     }
@@ -128,15 +129,7 @@ SecurityMode getAlternateFor(SecurityMode mode) {
      *
      * @return backup method or current security mode
      */
-    SecurityMode getBackupSecurityMode() {
-        SecurityMode mode = getSecurityMode();
-
-        // Note that getAlternateFor() cannot be called here because we want to get the backup for
-        // biometric unlock even if it's suppressed; it just has to be enabled.
-        if (isBiometricUnlockEnabled()
-                && (mode == SecurityMode.Password || mode == SecurityMode.Pattern)) {
-            mode = SecurityMode.Biometric;
-        }
+    SecurityMode getBackupSecurityMode(SecurityMode mode) {
         switch(mode) {
             case Biometric:
                 return getSecurityMode();