NativeScript · CatchABus · Feb 4, 2023 · Feb 4, 2023 · Feb 4, 2023 · Feb 5, 2023
diff --git a/packages/core/platforms/android/widgets-release.aar b/packages/core/platforms/android/widgets-release.aar
diff --git a/...obile-base/android/widgets/src/main/java/org/nativescript/widgets/CommonLayoutParams.java b/...obile-base/android/widgets/src/main/java/org/nativescript/widgets/CommonLayoutParams.java
@@ -96,6 +96,33 @@ protected static int getDesiredHeight(View view) {
 		return view.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;
 	}
 
+	protected static int getLayoutGravity(View child, boolean fitsWidth, boolean fitsHeight) {
+		CommonLayoutParams lp = (CommonLayoutParams) child.getLayoutParams();
+		int gravity = lp.gravity;
+
+		if (gravity == -1) {
+			gravity = Gravity.FILL;
+		}
+
+		// If gravity is FILL and content does not fill parent, we need it to be centered otherwise our explicit size won't be taken into account.
+		if (fitsWidth) {
+			int horizontalGravity = Gravity.getAbsoluteGravity(gravity, child.getLayoutDirection()) & Gravity.HORIZONTAL_GRAVITY_MASK;
+			if (horizontalGravity == Gravity.FILL_HORIZONTAL) {
+				gravity &= ~Gravity.FILL_HORIZONTAL;
+				gravity |= Gravity.CENTER_HORIZONTAL;
+			}
+		}
+		if (fitsHeight) {
+			int verticalGravity = gravity & Gravity.VERTICAL_GRAVITY_MASK;
+			if (verticalGravity == Gravity.FILL_VERTICAL) {
+				gravity &= ~Gravity.FILL_VERTICAL;
+				gravity |= Gravity.CENTER_VERTICAL;
+			}
+		}
+
+		return gravity;
+	}
+
 	// We use our own layout method because the one in FrameLayout is broken when margins are set and gravity is CENTER_VERTICAL or CENTER_HORIZONTAL.
 	@SuppressLint("RtlHardcoded")
 	protected static void layoutChild(View child, int left, int top, int right, int bottom) {
@@ -110,18 +137,9 @@ protected static void layoutChild(View child, int left, int top, int right, int
 		int childHeight = child.getMeasuredHeight();
 
 		CommonLayoutParams lp = (CommonLayoutParams) child.getLayoutParams();
-		int gravity = lp.gravity;
-		if (gravity == -1) {
-			gravity = Gravity.FILL;
-		}
-
-		int verticalGravity = gravity & Gravity.VERTICAL_GRAVITY_MASK;
-
-		// If we have explicit height and gravity is FILL we need to be centered otherwise our explicit height won't be taken into account.
-		if ((lp.height >= 0 || lp.heightPercent > 0) && verticalGravity == Gravity.FILL_VERTICAL) {
-			verticalGravity = Gravity.CENTER_VERTICAL;
-		}
-
+		final int gravity = CommonLayoutParams.getLayoutGravity(child, (lp.width >= 0 || lp.widthPercent > 0), (lp.height >= 0 || lp.heightPercent > 0));
+
+		final int verticalGravity = gravity & Gravity.VERTICAL_GRAVITY_MASK;
 		switch (verticalGravity) {
 			case Gravity.TOP:
 				childTop = top + lp.topMargin;
@@ -142,13 +160,7 @@ protected static void layoutChild(View child, int left, int top, int right, int
 				break;
 		}
 
-		int horizontalGravity = Gravity.getAbsoluteGravity(gravity, child.getLayoutDirection()) & Gravity.HORIZONTAL_GRAVITY_MASK;
-
-		// If we have explicit width and gravity is FILL we need to be centered otherwise our explicit width won't be taken into account.
-		if ((lp.width >= 0 || lp.widthPercent > 0) && horizontalGravity == Gravity.FILL_HORIZONTAL) {
-			horizontalGravity = Gravity.CENTER_HORIZONTAL;
-		}
-
+		final int horizontalGravity = Gravity.getAbsoluteGravity(gravity, child.getLayoutDirection()) & Gravity.HORIZONTAL_GRAVITY_MASK;
 		switch (horizontalGravity) {
 			case Gravity.LEFT:
 				childLeft = left + lp.leftMargin;

diff --git a/...ile-base/android/widgets/src/main/java/org/nativescript/widgets/HorizontalScrollView.java b/...ile-base/android/widgets/src/main/java/org/nativescript/widgets/HorizontalScrollView.java
@@ -1,45 +1,22 @@
 package org.nativescript.widgets;
 
 import android.content.Context;
-import android.graphics.Rect;
-import android.os.Parcel;
-import android.os.Parcelable;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
-import android.view.ViewParent;
 import android.widget.FrameLayout;
 
-import androidx.annotation.NonNull;
-
 /**
  * @author hhristov
  */
 public class HorizontalScrollView extends android.widget.HorizontalScrollView {
 
-	private final Rect mTempRect = new Rect();
-
 	private int contentMeasuredWidth = 0;
 	private int contentMeasuredHeight = 0;
 	private int scrollableLength = 0;
-	private SavedState mSavedState;
-	private boolean isFirstLayout = true;
 	private boolean scrollEnabled = true;
 
-	/**
-	 * True when the layout has changed but the traversal has not come through yet.
-	 * Ideally the view hierarchy would keep track of this for us.
-	 */
-	private boolean mIsLayoutDirty = true;
-
-	/**
-	 * The child to give focus to in the event that a child has requested focus while the
-	 * layout is dirty. This prevents the scroll from being wrong if the child has not been
-	 * laid out before requesting focus.
-	 */
-	private View mChildToScrollTo = null;
-
 	public HorizontalScrollView(Context context) {
 		super(context);
 	}
@@ -75,12 +52,6 @@ public boolean onTouchEvent(MotionEvent ev) {
 		return super.onTouchEvent(ev);
 	}
 
-	@Override
-	public void requestLayout() {
-		this.mIsLayoutDirty = true;
-		super.requestLayout();
-	}
-
 	@Override
 	protected CommonLayoutParams generateDefaultLayoutParams() {
 		return new CommonLayoutParams();
@@ -116,17 +87,6 @@ protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams fro
 		return new CommonLayoutParams(from);
 	}
 
-	@Override
-	public void requestChildFocus(View child, View focused) {
-		if (!mIsLayoutDirty) {
-			this.scrollToChild(focused);
-		} else {
-			// The child may not be laid out yet, we can't compute the scroll yet
-			mChildToScrollTo = focused;
-		}
-		super.requestChildFocus(child, focused);
-	}
-
 	@Override
 	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 		CommonLayoutParams.adjustChildrenLayoutParams(this, widthMeasureSpec, heightMeasureSpec);
@@ -138,13 +98,26 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 			this.scrollableLength = 0;
 			this.contentMeasuredWidth = 0;
 			this.contentMeasuredHeight = 0;
+
+			this.setPadding(0, 0, 0, 0);
 		} else {
-			CommonLayoutParams.measureChild(child, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), heightMeasureSpec);
+			CommonLayoutParams lp = (CommonLayoutParams) child.getLayoutParams();
+
+			final int childWidthMeasureSpec;
+
+			final int availableWidth = MeasureSpec.getSize(widthMeasureSpec) - lp.leftMargin - lp.rightMargin;
+			final int childWidth = child.getMeasuredWidth();
+			if (lp.width == LayoutParams.MATCH_PARENT && childWidth > 0 && childWidth < availableWidth) {
+				childWidthMeasureSpec = widthMeasureSpec;
+			} else {
+				childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
+			}
+
+			CommonLayoutParams.measureChild(child, childWidthMeasureSpec, heightMeasureSpec);
 			this.contentMeasuredWidth = CommonLayoutParams.getDesiredWidth(child);
 			this.contentMeasuredHeight = CommonLayoutParams.getDesiredHeight(child);
 
 			// Android ScrollView does not account to child margins so we set them as paddings. Otherwise you can never scroll to bottom.
-			CommonLayoutParams lp = (CommonLayoutParams) child.getLayoutParams();
 			this.setPadding(lp.leftMargin, lp.topMargin, lp.rightMargin, lp.bottomMargin);
 		}
 
@@ -165,151 +138,44 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 
 	@Override
 	protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
-		int childWidth = 0;
-		if (this.getChildCount() > 0) {
-			View child = this.getChildAt(0);
-			childWidth = child.getMeasuredWidth();
-
-			int width = right - left;
-			int height = bottom - top;
-
-			this.scrollableLength = this.contentMeasuredWidth - width;
-			CommonLayoutParams.layoutChild(child, 0, 0, Math.max(this.contentMeasuredWidth, width), height);
-			this.scrollableLength = Math.max(0, this.scrollableLength);
-		}
-
-		this.mIsLayoutDirty = false;
-		// Give a child focus if it needs it
-		if (this.mChildToScrollTo != null && isViewDescendantOf(this.mChildToScrollTo, this)) {
-			this.scrollToChild(this.mChildToScrollTo);
-		}
+		final int width = right - left;
+		final int height = bottom - top;
 
-		this.mChildToScrollTo = null;
-
-		int scrollX = this.getScrollX();
-		int scrollY = this.getScrollY();
-
-		if (this.isFirstLayout) {
-			this.isFirstLayout = false;
-
-			final int scrollRange = Math.max(0, childWidth - (right - left - this.getPaddingLeft() - this.getPaddingRight()));
-			if (this.mSavedState != null) {
-				scrollX = (this.isLayoutRtl() == mSavedState.isLayoutRtl) ? mSavedState.scrollPosition : (scrollRange - this.mSavedState.scrollPosition);
-				mSavedState = null;
-			} else {
-				if (this.isLayoutRtl()) {
-					scrollX = scrollRange - scrollX;
-				} // mScrollX default value is "0" for LTR
-			}
-			// Don't forget to clamp
-			if (scrollX > scrollRange) {
-				scrollX = scrollRange;
-			} else if (scrollX < 0) {
-				scrollX = 0;
-			}
+		if (this.getChildCount() > 0) {
+			final View child = this.getChildAt(0);
+			final CommonLayoutParams childLayoutParams = (CommonLayoutParams) child.getLayoutParams();
+
+			final int leftMargin = childLayoutParams.leftMargin;
+			final int topMargin = childLayoutParams.topMargin;
+			final int rightMargin = childLayoutParams.rightMargin;
+			final int bottomMargin = childLayoutParams.bottomMargin;
+			final int gravity = childLayoutParams.gravity;
+
+			// Android scrollviews don't handle margins very well, so unset margin values and set their values anew when layout calculations are done
+			childLayoutParams.leftMargin = 0;
+			childLayoutParams.topMargin = 0;
+			childLayoutParams.rightMargin = 0;
+			childLayoutParams.bottomMargin = 0;
+
+			// This will apply gravity defaults if needed
+			childLayoutParams.gravity = CommonLayoutParams.getLayoutGravity(child, (childLayoutParams.width >= 0 && childLayoutParams.width < width), 
+				(childLayoutParams.height >= 0 && childLayoutParams.height < height));
+
+			super.onLayout(changed, left, top, right, bottom);
+
+			// View has finished laying out child, set margin values back
+			childLayoutParams.leftMargin = leftMargin;
+			childLayoutParams.topMargin = topMargin;
+			childLayoutParams.rightMargin = rightMargin;
+			childLayoutParams.bottomMargin = bottomMargin;
+
+			// Set previous gravity value
+			childLayoutParams.gravity = gravity;
+		} else {
+			super.onLayout(changed, left, top, right, bottom);
 		}
 
-		// Calling this with the present values causes it to re-claim them
-		this.scrollTo(scrollX, scrollY);
+		this.scrollableLength = Math.max(0, this.contentMeasuredWidth - width);
 		CommonLayoutParams.restoreOriginalParams(this);
 	}
-
-	@Override
-	protected void onAttachedToWindow() {
-		super.onAttachedToWindow();
-		this.isFirstLayout = true;
-	}
-
-	@Override
-	protected void onDetachedFromWindow() {
-		super.onDetachedFromWindow();
-		this.isFirstLayout = true;
-	}
-
-	@Override
-	protected void onRestoreInstanceState(Parcelable state) {
-		SavedState ss = (SavedState) state;
-		super.onRestoreInstanceState(ss.getSuperState());
-		this.mSavedState = ss;
-		this.requestLayout();
-	}
-
-	@Override
-	protected Parcelable onSaveInstanceState() {
-		Parcelable superState = super.onSaveInstanceState();
-		SavedState ss = new SavedState(superState);
-		ss.scrollPosition = this.getScrollX();
-		ss.isLayoutRtl = this.isLayoutRtl();
-		return ss;
-	}
-
-	private void scrollToChild(View child) {
-		child.getDrawingRect(mTempRect);
-
-		/* Offset from child's local coordinates to ScrollView coordinates */
-		offsetDescendantRectToMyCoords(child, mTempRect);
-
-		int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect);
-		if (scrollDelta != 0) {
-			this.scrollBy(scrollDelta, 0);
-		}
-	}
-
-	private boolean isLayoutRtl() {
-		return (this.getLayoutDirection() == LAYOUT_DIRECTION_RTL);
-	}
-
-	/**
-	 * Return true if child is a descendant of parent, (or equal to the parent).
-	 */
-	static boolean isViewDescendantOf(View child, View parent) {
-		if (child == parent) {
-			return true;
-		}
-
-		final ViewParent theParent = child.getParent();
-		return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent);
-	}
-
-	static class SavedState extends BaseSavedState {
-		public int scrollPosition;
-		public boolean isLayoutRtl;
-
-		SavedState(Parcelable superState) {
-			super(superState);
-		}
-
-		public SavedState(Parcel source) {
-			super(source);
-			scrollPosition = source.readInt();
-			isLayoutRtl = source.readInt() == 0;
-		}
-
-		@Override
-		public void writeToParcel(Parcel dest, int flags) {
-			super.writeToParcel(dest, flags);
-			dest.writeInt(scrollPosition);
-			dest.writeInt(isLayoutRtl ? 1 : 0);
-		}
-
-		@NonNull
-		@Override
-		public String toString() {
-			return "HorizontalScrollView.SavedState{"
-				+ Integer.toHexString(System.identityHashCode(this))
-				+ " scrollPosition=" + scrollPosition
-				+ " isLayoutRtl=" + isLayoutRtl + "}";
-		}
-
-		public static final Creator<SavedState> CREATOR
-			= new Creator<SavedState>() {
-			public SavedState createFromParcel(Parcel in) {
-				return new SavedState(in);
-			}
-
-			public SavedState[] newArray(int size) {
-				return new SavedState[size];
-			}
-		};
-	}
 }