Better biometric subtitle with createConfirmDeviceCredentialIntent() API

Test: Tested manually with repro steps

Fixes: 224967328
Change-Id: I788abc0714502cbf857d8e18d51e69a5d54a0387

core/java/android/hardware/biometrics/BiometricPrompt.java

@@ -187,6 +187,19 @@ public class BiometricPrompt implements BiometricAuthenticator, BiometricConstan
             return this;
         }
 
+        /**
+         * Shows a default subtitle for the prompt if the subtitle would otherwise be
+         * null or empty. Currently for internal use only.
+         * @return This builder.
+         * @hide
+         */
+        @RequiresPermission(USE_BIOMETRIC_INTERNAL)
+        @NonNull
+        public Builder setUseDefaultSubtitle() {
+            mPromptInfo.setUseDefaultSubtitle(true);
+            return this;
+        }
+
         /**
          * Optional: Sets a description that will be shown on the prompt.
          * @param description The description to display.
@@ -628,6 +641,16 @@ public class BiometricPrompt implements BiometricAuthenticator, BiometricConstan
         return mPromptInfo.getSubtitle();
     }
 
+    /**
+     * Whether to use a default subtitle. For internal use only.
+     * @return See {@link Builder#setUseDefaultSubtitle()}.
+     * @hide
+     */
+    @RequiresPermission(USE_BIOMETRIC_INTERNAL)
+    public boolean shouldUseDefaultSubtitle() {
+        return mPromptInfo.isUseDefaultSubtitle();
+    }
+
     /**
      * Gets the description for the prompt, as set by {@link Builder#setDescription(CharSequence)}.
      * @return The description for the prompt, or null if the prompt has no description.

core/java/android/hardware/biometrics/PromptInfo.java

@@ -33,6 +33,7 @@ public class PromptInfo implements Parcelable {
     @NonNull private CharSequence mTitle;
     private boolean mUseDefaultTitle;
     @Nullable private CharSequence mSubtitle;
+    private boolean mUseDefaultSubtitle;
     @Nullable private CharSequence mDescription;
     @Nullable private CharSequence mDeviceCredentialTitle;
     @Nullable private CharSequence mDeviceCredentialSubtitle;
@@ -56,6 +57,7 @@ public class PromptInfo implements Parcelable {
         mTitle = in.readCharSequence();
         mUseDefaultTitle = in.readBoolean();
         mSubtitle = in.readCharSequence();
+        mUseDefaultSubtitle = in.readBoolean();
         mDescription = in.readCharSequence();
         mDeviceCredentialTitle = in.readCharSequence();
         mDeviceCredentialSubtitle = in.readCharSequence();
@@ -94,6 +96,7 @@ public class PromptInfo implements Parcelable {
         dest.writeCharSequence(mTitle);
         dest.writeBoolean(mUseDefaultTitle);
         dest.writeCharSequence(mSubtitle);
+        dest.writeBoolean(mUseDefaultSubtitle);
         dest.writeCharSequence(mDescription);
         dest.writeCharSequence(mDeviceCredentialTitle);
         dest.writeCharSequence(mDeviceCredentialSubtitle);
@@ -128,6 +131,8 @@ public class PromptInfo implements Parcelable {
             return true;
         } else if (mUseDefaultTitle) {
             return true;
+        } else if (mUseDefaultSubtitle) {
+            return true;
         } else if (mDeviceCredentialTitle != null) {
             return true;
         } else if (mDeviceCredentialSubtitle != null) {
@@ -154,6 +159,10 @@ public class PromptInfo implements Parcelable {
         mSubtitle = subtitle;
     }
 
+    public void setUseDefaultSubtitle(boolean useDefaultSubtitle) {
+        mUseDefaultSubtitle = useDefaultSubtitle;
+    }
+
     public void setDescription(CharSequence description) {
         mDescription = description;
     }
@@ -227,6 +236,10 @@ public class PromptInfo implements Parcelable {
         return mSubtitle;
     }
 
+    public boolean isUseDefaultSubtitle() {
+        return mUseDefaultSubtitle;
+    }
+
     public CharSequence getDescription() {
         return mDescription;
     }

services/core/java/com/android/server/biometrics/BiometricService.java

@@ -563,6 +563,14 @@ public class BiometricService extends SystemService {
                 }
             }
 
+            // Set the default subtitle if necessary.
+            if (promptInfo.isUseDefaultSubtitle()) {
+                if (TextUtils.isEmpty(promptInfo.getSubtitle())) {
+                    promptInfo.setSubtitle(getContext()
+                            .getString(R.string.biometric_dialog_default_subtitle));
+                }
+            }
+
             final long requestId = mRequestCounter.get();
             mHandler.post(() -> handleAuthenticate(
                     token, requestId, operationId, userId, receiver, opPackageName, promptInfo));