Uses static top padding for lockscreen notification space

This removes the usage of NSSLC.getTopPadding() to calculate the number of notifications to display, and uses a static value.

+ Make debugging lines for notification available space more clear.

+ Renamed getMinStackScrollerPadding, as it was used only in Lockscreen.

Fixes: 230083553
Test: Enabled debug lines for visual inspection & made sure notifications don't change count when coming back from camera started from lockscreen
Change-Id: I139d25e2bb57257a18f18f6288f3e18b7a1b72d1

packages/SystemUI/src/com/android/systemui/statusbar/phone/KeyguardClockPositionAlgorithm.java

@@ -220,7 +220,7 @@ public class KeyguardClockPositionAlgorithm {
         }
     }
 
-    public float getMinStackScrollerPadding() {
+    public float getLockscreenMinStackScrollerPadding() {
         if (mBypassEnabled) {
             return mUnlockedStackScrollerPadding;
         } else if (mIsSplitShade) {

packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelViewController.java

@@ -325,6 +325,11 @@ public class NotificationPanelViewController extends PanelViewController {
     private boolean mShouldUseSplitNotificationShade;
     // The bottom padding reserved for elements of the keyguard measuring notifications
     private float mKeyguardNotificationBottomPadding;
+    /**
+     * The top padding from where notification should start in lockscreen.
+     * Should be static also during animations and should match the Y of the first notification.
+     */
+    private float mKeyguardNotificationTopPadding;
     // Current max allowed keyguard notifications determined by measuring the panel
     private int mMaxAllowedKeyguardNotifications;
 
@@ -1513,7 +1518,10 @@ public class NotificationPanelViewController extends PanelViewController {
      */
     @VisibleForTesting
     float getSpaceForLockscreenNotifications() {
-        float topPadding = mNotificationStackScrollLayoutController.getTopPadding();
+        float staticTopPadding = mClockPositionAlgorithm.getLockscreenMinStackScrollerPadding()
+                // getMinStackScrollerPadding is from the top of the screen,
+                // but we need it from the top of the NSSL.
+                - mNotificationStackScrollLayoutController.getTop();
 
         // Space between bottom of notifications and top of lock icon or udfps background.
         float lockIconPadding = mLockIconViewController.getTop();
@@ -1525,11 +1533,15 @@ public class NotificationPanelViewController extends PanelViewController {
 
         float bottomPadding = Math.max(lockIconPadding,
                 Math.max(mIndicationBottomPadding, mAmbientIndicationBottomPadding));
-        mKeyguardNotificationBottomPadding = bottomPadding;
 
+        mKeyguardNotificationBottomPadding = bottomPadding;
+        mKeyguardNotificationTopPadding = staticTopPadding;
+
+        // To debug the available space, enable debug lines in this class. If you change how the
+        // available space is calculated, please also update those lines.
         float availableSpace =
                 mNotificationStackScrollLayoutController.getHeight()
-                        - topPadding
+                        - staticTopPadding
                         - bottomPadding;
         return availableSpace;
     }
@@ -4923,6 +4935,20 @@ public class NotificationPanelViewController extends PanelViewController {
             drawDebugInfo(canvas, (int) mLockIconViewController.getTop(), Color.GRAY,
                     "mLockIconViewController.getTop()");
 
+            if (mKeyguardShowing) {
+                // Notifications have the space between those two lines.
+                drawDebugInfo(canvas,
+                        mNotificationStackScrollLayoutController.getTop() +
+                                (int) mKeyguardNotificationTopPadding,
+                        Color.RED,
+                        "NSSL.getTop() + mKeyguardNotificationTopPadding");
+
+                drawDebugInfo(canvas, mNotificationStackScrollLayoutController.getBottom() -
+                                (int) mKeyguardNotificationBottomPadding,
+                        Color.RED,
+                        "NSSL.getBottom() - mKeyguardNotificationBottomPadding");
+            }
+
             mDebugPaint.setColor(Color.CYAN);
             canvas.drawLine(0, mClockPositionResult.stackScrollerPadding, mView.getWidth(),
                     mNotificationStackScrollLayoutController.getTopPadding(), mDebugPaint);

packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/KeyguardClockPositionAlgorithmTest.java

@@ -336,7 +336,7 @@ public class KeyguardClockPositionAlgorithmTest extends SysuiTestCase {
         // WHEN the position algorithm is run
         positionClock();
         // THEN the padding DOESN'T adjust for keyguard status height.
-        assertThat(mClockPositionAlgorithm.getMinStackScrollerPadding())
+        assertThat(mClockPositionAlgorithm.getLockscreenMinStackScrollerPadding())
                 .isEqualTo(mKeyguardStatusBarHeaderHeight);
     }
 

packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/NotificationPanelViewControllerTest.java

@@ -610,13 +610,13 @@ public class NotificationPanelViewControllerTest extends SysuiTestCase {
         when(mLockIconViewController.getTop()).thenReturn(80f);
         when(mResources.getDimensionPixelSize(R.dimen.shelf_and_lock_icon_overlap)).thenReturn(5);
 
-        // Available space (100 - 10 - 15 = 75)
+        // Available space (100 - 0 - 15 = 85)
         when(mNotificationStackScrollLayoutController.getHeight()).thenReturn(100);
-        when(mNotificationStackScrollLayoutController.getTopPadding()).thenReturn(10);
+        when(mNotificationStackScrollLayoutController.getTop()).thenReturn(0);
         mNotificationPanelViewController.updateResources();
 
         assertThat(mNotificationPanelViewController.getSpaceForLockscreenNotifications())
-                .isEqualTo(75);
+                .isEqualTo(85);
     }
 
     @Test