android.view.View#isScrollContainer ( )源码实例Demo

/**
 * Determines if the supplied {@link View} is a top-level item within a scrollable container.
 *
 * @param view The {@link View} to evaluate
 * @return {@code true} if {@code view} is a top-level view within a scrollable container, {@code
 *     false} otherwise
 */
@RequiresApi(Build.VERSION_CODES.JELLY_BEAN) // Calls View#getParentForAccessibility
private static boolean isChildOfScrollableContainer(View view) {
  if (view == null) {
    return false;
  }

  ViewParent viewParent = view.getParentForAccessibility();
  if ((viewParent == null) || !(viewParent instanceof View)) {
    return false;
  }

  View parent = (View) viewParent;
  if (parent.isScrollContainer()) {
    return true;
  }

  // Specifically check for parents that are AdapterView, ScrollView, or HorizontalScrollView, but
  // exclude Spinners, which are a special case of AdapterView.
  return (((parent instanceof AdapterView)
          || (parent instanceof ScrollView)
          || (parent instanceof HorizontalScrollView))
      && !(parent instanceof Spinner));
}
 

/**
 * 获取 View 是否需要滚动效应
 * @param view {@link View}
 * @return {@code true} yes, {@code false} no
 */
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
public static boolean isScrollContainer(final View view) {
    if (view != null) {
        return view.isScrollContainer();
    }
    return false;
}
 

Builder(int id, @Nullable ViewHierarchyElementAndroid parent, View fromView) {
  // Bookkeeping
  this.id = id;
  this.parentId = (parent != null) ? parent.getId() : null;

  this.drawingOrder = null;

  // API 16+ properties
  this.scrollable = AT_16 ? fromView.isScrollContainer() : null;

  // API 11+ properties
  this.backgroundDrawableColor =
      (AT_11 && (fromView != null) && (fromView.getBackground() instanceof ColorDrawable))
          ? ((ColorDrawable) fromView.getBackground()).getColor()
          : null;

  // Base properties
  this.visibleToUser = ViewAccessibilityUtils.isVisibleToUser(fromView);
  this.className = fromView.getClass().getName();
  this.accessibilityClassName = null;
  this.packageName = fromView.getContext().getPackageName();
  this.resourceName =
      (fromView.getId() != View.NO_ID)
          ? ViewAccessibilityUtils.getResourceNameForView(fromView)
          : null;
  this.contentDescription = SpannableStringAndroid.valueOf(fromView.getContentDescription());
  this.enabled = fromView.isEnabled();
  if (fromView instanceof TextView) {
    TextView textView = (TextView) fromView;
    // Hint text takes precedence if no text is present.
    CharSequence text = textView.getText();
    if (TextUtils.isEmpty(text)) {
      text = textView.getHint();
    }
    this.text = SpannableStringAndroid.valueOf(text);
    this.textSize = textView.getTextSize();

    this.textColor = textView.getCurrentTextColor();
    this.typefaceStyle =
        (textView.getTypeface() != null) ? textView.getTypeface().getStyle() : null;
  } else {
    this.text = null;
    this.textSize = null;
    this.textColor = null;
    this.typefaceStyle = null;
  }

  this.importantForAccessibility = ViewAccessibilityUtils.isImportantForAccessibility(fromView);
  this.clickable = fromView.isClickable();
  this.longClickable = fromView.isLongClickable();
  this.focusable = fromView.isFocusable();
  this.editable = ViewAccessibilityUtils.isViewEditable(fromView);
  this.canScrollForward =
      (ViewCompat.canScrollVertically(fromView, 1)
          || ViewCompat.canScrollHorizontally(fromView, 1));
  this.canScrollBackward =
      (ViewCompat.canScrollVertically(fromView, -1)
          || ViewCompat.canScrollHorizontally(fromView, -1));
  this.checkable = (fromView instanceof Checkable);
  this.checked = (fromView instanceof Checkable) ? ((Checkable) fromView).isChecked() : null;
  this.hasTouchDelegate = (fromView.getTouchDelegate() != null);
  this.touchDelegateBounds = ImmutableList.of(); // Unavailable from the View API
  this.boundsInScreen = getBoundsInScreen(fromView);
  this.nonclippedHeight = fromView.getHeight();
  this.nonclippedWidth = fromView.getWidth();
  this.actionList = ImmutableList.of(); // Unavailable from the View API
}