Fix biometric content overlap with top/bottom bars

Sets a solid background for the status and footer bar shown on each of
the biometric enroll introduction screens, to prevent the content from
showing through.

Test: Manually tested face and fingerprint enrollment

Fixes: 189075189
Change-Id: I1a41dc911c5ac7ded94e33b25a9c0e990e93ba3f

src/com/android/settings/biometrics/BiometricEnrollIntroduction.java

@@ -18,6 +18,8 @@ package com.android.settings.biometrics;
 
 import android.app.admin.DevicePolicyManager;
 import android.content.Intent;
+import android.content.res.ColorStateList;
+import android.graphics.Color;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffColorFilter;
 import android.os.Bundle;
@@ -25,14 +27,17 @@ import android.os.UserHandle;
 import android.os.UserManager;
 import android.util.Log;
 import android.view.View;
+import android.widget.LinearLayout;
 import android.widget.TextView;
 
+import androidx.annotation.ColorInt;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import com.android.internal.widget.LockPatternUtils;
 import com.android.settings.R;
 import com.android.settings.SetupWizardUtils;
+import com.android.settings.Utils;
 import com.android.settings.password.ChooseLockGeneric;
 import com.android.settings.password.ChooseLockSettingsHelper;
 
@@ -182,6 +187,15 @@ public abstract class BiometricEnrollIntroduction extends BiometricEnrollBase
         }
     }
 
+    @Override
+    protected void onPostCreate(@Nullable Bundle savedInstanceState) {
+        super.onPostCreate(savedInstanceState);
+        final LinearLayout buttonContainer = mFooterBarMixin.getButtonContainer();
+        if (buttonContainer != null) {
+            buttonContainer.setBackgroundColor(getBackgroundColor());
+        }
+    }
+
     @Override
     protected void onResume() {
         super.onResume();
@@ -199,6 +213,12 @@ public abstract class BiometricEnrollIntroduction extends BiometricEnrollBase
         }
     }
 
+    @Override
+    public void onAttachedToWindow() {
+        super.onAttachedToWindow();
+        getWindow().setStatusBarColor(getBackgroundColor());
+    }
+
     @Override
     protected void onSaveInstanceState(Bundle outState) {
         super.onSaveInstanceState(outState);
@@ -335,4 +355,10 @@ public abstract class BiometricEnrollIntroduction extends BiometricEnrollBase
         }
         return mIconColorFilter;
     }
+
+    @ColorInt
+    private int getBackgroundColor() {
+        final ColorStateList stateList = Utils.getColorAttr(this, android.R.attr.windowBackground);
+        return stateList != null ? stateList.getDefaultColor() : Color.TRANSPARENT;
+    }
 }