Add lock screen help dialog.

app/src/main/AndroidManifest.xml

@@ -661,7 +661,7 @@
 
     <activity android:name=".PassphrasePromptActivity"
               android:launchMode="singleTask"
-              android:theme="@style/TextSecure.LightIntroTheme"
+              android:theme="@style/Theme.Signal.DayNight.NoActionBar"
               android:configChanges="touchscreen|keyboard|keyboardHidden|orientation|screenLayout|screenSize"
               android:exported="false"/>
 

app/src/main/java/org/thoughtcrime/securesms/PassphrasePromptActivity.java

@@ -44,10 +44,13 @@ import android.widget.ImageView;
 import android.widget.TextView;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.appcompat.widget.Toolbar;
 import androidx.biometric.BiometricManager;
 import androidx.biometric.BiometricPrompt;
 
+import com.google.android.material.dialog.MaterialAlertDialogBuilder;
+
 import org.signal.core.util.ThreadUtil;
 import org.signal.core.util.logging.Log;
 import org.thoughtcrime.securesms.animation.AnimationCompleteListener;
@@ -55,6 +58,7 @@ import org.thoughtcrime.securesms.components.AnimatingToggle;
 import org.thoughtcrime.securesms.crypto.InvalidPassphraseException;
 import org.thoughtcrime.securesms.crypto.MasterSecret;
 import org.thoughtcrime.securesms.crypto.MasterSecretUtil;
+import org.thoughtcrime.securesms.keyvalue.SignalStore;
 import org.thoughtcrime.securesms.logsubmit.SubmitDebugLogActivity;
 import org.thoughtcrime.securesms.util.CommunicationActions;
 import org.thoughtcrime.securesms.util.DynamicIntroTheme;
@@ -74,7 +78,8 @@ public class PassphrasePromptActivity extends PassphraseActivity {
   private static final String TAG                       = Log.tag(PassphrasePromptActivity.class);
   private static final short  AUTHENTICATE_REQUEST_CODE = 1007;
   private static final String BUNDLE_ALREADY_SHOWN      = "bundle_already_shown";
-  public static final  String FROM_FOREGROUND           = "from_foreground";
+  public  static final String FROM_FOREGROUND           = "from_foreground";
+  private static final int    HELP_COUNT_THRESHOLD      = 3;
 
   private DynamicIntroTheme dynamicTheme    = new DynamicIntroTheme();
   private DynamicLanguage   dynamicLanguage = new DynamicLanguage();
@@ -188,6 +193,7 @@ public class PassphrasePromptActivity extends PassphraseActivity {
     } else {
       Log.w(TAG, "Authentication failed");
       hadFailure = true;
+      incrementAttemptCountAndShowHelpIfNecessary();
     }
   }
 
@@ -207,6 +213,7 @@ public class PassphrasePromptActivity extends PassphraseActivity {
       passphraseText.setText("");
       passphraseText.setError(
               getString(R.string.PassphrasePromptActivity_invalid_passphrase_exclamation));
+      incrementAttemptCountAndShowHelpIfNecessary();
     }
   }
 
@@ -216,6 +223,7 @@ public class PassphrasePromptActivity extends PassphraseActivity {
       
       MasterSecret masterSecret = MasterSecretUtil.getMasterSecret(this, MasterSecretUtil.UNENCRYPTED_PASSPHRASE);
       setMasterSecret(masterSecret);
+      SignalStore.misc().setLockScreenAttemptCount(0);
     } catch (InvalidPassphraseException e) {
       throw new AssertionError(e);
     }
@@ -272,6 +280,10 @@ public class PassphrasePromptActivity extends PassphraseActivity {
     fingerprintPrompt.getBackground().setColorFilter(getResources().getColor(R.color.core_ultramarine), PorterDuff.Mode.SRC_IN);
 
     lockScreenButton.setOnClickListener(v -> resumeScreenLock(true));
+
+    if (SignalStore.misc().getLockScreenAttemptCount() > HELP_COUNT_THRESHOLD) {
+      showHelpDialogAndResetAttemptCount(null);
+    }
   }
 
   private void setLockTypeVisibility() {
@@ -288,6 +300,10 @@ public class PassphrasePromptActivity extends PassphraseActivity {
   }
 
   private void resumeScreenLock(boolean force) {
+    if (incrementAttemptCountAndShowHelpIfNecessary(() -> resumeScreenLock(force))) {
+      return;
+    }
+
     if (!biometricAuth.authenticate(getApplicationContext(), force, this::showConfirmDeviceCredentialIntent)) {
       handleAuthenticated();
     }
@@ -312,6 +328,33 @@ public class PassphrasePromptActivity extends PassphraseActivity {
     return Unit.INSTANCE;
   }
 
+  private boolean incrementAttemptCountAndShowHelpIfNecessary() {
+    return incrementAttemptCountAndShowHelpIfNecessary(null);
+  }
+
+  private boolean incrementAttemptCountAndShowHelpIfNecessary(Runnable onDismissed) {
+    SignalStore.misc().incrementLockScreenAttemptCount();
+
+    if (SignalStore.misc().getLockScreenAttemptCount() > HELP_COUNT_THRESHOLD) {
+      showHelpDialogAndResetAttemptCount(onDismissed);
+      return true;
+    }
+
+    return false;
+  }
+
+  private void showHelpDialogAndResetAttemptCount(@Nullable Runnable onDismissed) {
+    new MaterialAlertDialogBuilder(this)
+        .setMessage(R.string.PassphrasePromptActivity_help_prompt_body)
+        .setPositiveButton(android.R.string.ok, (dialog, which) -> {
+          SignalStore.misc().setLockScreenAttemptCount(0);
+          if (onDismissed != null) {
+            onDismissed.run();
+          }
+        })
+        .show();
+  }
+
   private class PassphraseActionListener implements TextView.OnEditorActionListener {
     @Override
     public boolean onEditorAction(TextView exampleView, int actionId, KeyEvent keyEvent) {
@@ -366,6 +409,8 @@ public class PassphrasePromptActivity extends PassphraseActivity {
       Log.w(TAG, "Authentication error: " + errorCode);
       hadFailure = true;
 
+      incrementAttemptCountAndShowHelpIfNecessary();
+
       if (errorCode != BiometricPrompt.ERROR_CANCELED && errorCode != BiometricPrompt.ERROR_USER_CANCELED) {
         onAuthenticationFailed();
       }

app/src/main/java/org/thoughtcrime/securesms/keyvalue/MiscellaneousValues.kt

@@ -36,6 +36,7 @@ class MiscellaneousValues internal constructor(store: KeyValueStore) : SignalSto
     private const val LINKED_DEVICE_LAST_ACTIVE_CHECK_TIME = "misc.linked_device.last_active_check_time"
     private const val LEAST_ACTIVE_LINKED_DEVICE = "misc.linked_device.least_active"
     private const val NEXT_DATABASE_ANALYSIS_TIME = "misc.next_database_analysis_time"
+    private const val LOCK_SCREEN_ATTEMPT_COUNT = "misc.lock_screen_attempt_count"
   }
 
   public override fun onFirstEverAppLaunch() {
@@ -248,4 +249,13 @@ class MiscellaneousValues internal constructor(store: KeyValueStore) : SignalSto
    * When the next scheduled database analysis is.
    */
   var nextDatabaseAnalysisTime: Long by longValue(NEXT_DATABASE_ANALYSIS_TIME, 0)
+
+  /**
+   * How many times the lock screen has been seen and _not_ unlocked. Used to determine if the user is confused by how to bypass the lock screen.
+   */
+  var lockScreenAttemptCount: Int by integerValue(LOCK_SCREEN_ATTEMPT_COUNT, 0)
+
+  fun incrementLockScreenAttemptCount() {
+    lockScreenAttemptCount++
+  }
 }

app/src/main/res/values/strings.xml

@@ -7127,6 +7127,8 @@
     <string name="RemoteBackupsSettingsFragment__monthly">Monthly</string>
     <!-- Title for frequency option DAILY for backup frequency -->
     <string name="RemoteBackupsSettingsFragment__manually_back_up">Manually back up</string>
+    <!-- The body of an alert dialog shown when we detect the user may be confused by the lock screen -->
+    <string name="PassphrasePromptActivity_help_prompt_body">Please enter your device pin, password or pattern.</string>
 
     <!-- EOF -->
 </resources>