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

/**
 * Returns a matrix of size same as the {@link CellLayout} dimension that is initialized with the
 * index of the child view.
 */
// TODO: get rid of the dynamic matrix creation
public static int[][] createSparseMatrix(CellLayout layout) {
    ShortcutAndWidgetContainer parent = layout.getShortcutsAndWidgets();
    final int m = layout.getCountX();
    final int n = layout.getCountY();
    final boolean invert = parent.invertLayoutHorizontally();

    int[][] matrix = createFullMatrix(m, n);

    // Iterate thru the children.
    for (int i = 0; i < parent.getChildCount(); i++ ) {
        View cell = parent.getChildAt(i);
        if (!cell.isFocusable()) {
            continue;
        }
        int cx = ((CellLayout.LayoutParams) cell.getLayoutParams()).cellX;
        int cy = ((CellLayout.LayoutParams) cell.getLayoutParams()).cellY;
        matrix[invert ? (m - cx - 1) : cx][cy] = i;
    }
    return matrix;
}
 

protected void handleStateOnResult(LayoutChunkResult result, View view) {
    if (view == null) {
        return;
    }

    RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();

    // Consume the available space if the view is not removed OR changed
    if (params.isItemRemoved() || params.isItemChanged()) {
        result.mIgnoreConsumed = true;
    }

    // used when search a focusable view
    result.mFocusable = result.mFocusable || view.isFocusable();

}
 

private void getFocusableViews(View view, final List<View> focusables) {
    // Not using addFocusables() or addTouchables() because of concerns with adding ViewGroup
    // and not getting "clickables."

    if (!(view instanceof ViewGroup) && (view != null) &&
            (view.isFocusable() || view.isClickable())) {
        focusables.add(view);
    }

    if (view instanceof ViewGroup) {
        ViewGroup parent = (ViewGroup) view;

        for (int i = 0; i < parent.getChildCount(); i++) {
            getFocusableViews(parent.getChildAt(i), focusables);
        }
    }
}
 

/**
 * Scrolls to the element with the given label (<a name...) and focuses it
 * (if focusable).
 */
public void gotoLabel(String label) {
  View v = label == null ? this : labels.get(label);
  if (v != null) {
    if (v.isFocusable()) {
      v.requestFocus();
    }
    int y = v.getTop();
    ViewParent parent = v.getParent();
    while (parent instanceof View) {
      if (parent instanceof ScrollView) {
        ((ScrollView) parent).smoothScrollTo(0, y);
        break;
      }
      y += ((View) parent).getTop();
      parent = parent.getParent();
    }
  }
}
 

/**
 * 获取 View 是否可以获取焦点
 * @param view {@link View}
 * @return {@code true} 可获取, {@code false} 不可获取
 */
public static boolean isFocusable(final View view) {
    if (view != null) {
        return view.isFocusable();
    }
    return false;
}
 

@Override
public View onFocusSearchFailed(View focused, int focusDirection,
                                RecyclerView.Recycler recycler,
                                RecyclerView.State state) {
    resolveShouldLayoutReverse();
    if (getChildCount() == 0) {
        return null;
    }

    final int layoutDir = convertFocusDirectionToLayoutDirection(focusDirection);
    if (layoutDir == RenderState.INVALID_LAYOUT) {
        return null;
    }
    final View referenceChild;
    if (layoutDir == RenderState.LAYOUT_START) {
        referenceChild = getChildClosestToStart();
    } else {
        referenceChild = getChildClosestToEnd();
    }
    ensureRenderState();
    final int maxScroll = (int) (MAX_SCROLL_FACTOR * (mOrientationHelper.getEndAfterPadding() -
            mOrientationHelper.getStartAfterPadding()));
    updateRenderState(layoutDir, maxScroll, false, state);
    mRenderState.mScrollingOffset = RenderState.SCOLLING_OFFSET_NaN;
    fill(recycler, mRenderState, state, true);
    final View nextFocus;
    if (layoutDir == RenderState.LAYOUT_START) {
        nextFocus = getChildClosestToStart();
    } else {
        nextFocus = getChildClosestToEnd();
    }
    if (nextFocus == referenceChild || !nextFocus.isFocusable()) {
        return null;
    }
    return nextFocus;
}
 

private static View getFirstFocusableIconInReadingOrder(CellLayout cellLayout, boolean isRtl) {
    View icon;
    int countX = cellLayout.getCountX();
    for (int y = 0; y < cellLayout.getCountY(); y++) {
        int increment = isRtl ? -1 : 1;
        for (int x = isRtl ? countX - 1 : 0; 0 <= x && x < countX; x += increment) {
            if ((icon = cellLayout.getChildAt(x, y)) != null && icon.isFocusable()) {
                return icon;
            }
        }
    }
    return null;
}
 

private static View getFirstFocusableIconInReverseReadingOrder(CellLayout cellLayout,
        boolean isRtl) {
    View icon;
    int countX = cellLayout.getCountX();
    for (int y = cellLayout.getCountY() - 1; y >= 0; y--) {
        int increment = isRtl ? 1 : -1;
        for (int x = isRtl ? 0 : countX - 1; 0 <= x && x < countX; x += increment) {
            if ((icon = cellLayout.getChildAt(x, y)) != null && icon.isFocusable()) {
                return icon;
            }
        }
    }
    return null;
}
 

/**
 * Creates a sparse matrix that merges the icon of previous/next page and last column of
 * current page. When left key is triggered on the leftmost column, sparse matrix is created
 * that combines previous page matrix and an extra column on the right. Likewise, when right
 * key is triggered on the rightmost column, sparse matrix is created that combines this column
 * on the 0th column and the next page matrix.
 *
 * @param pivotX    x coordinate of the focused item in the current page
 * @param pivotY    y coordinate of the focused item in the current page
 */
// TODO: get rid of the dynamic matrix creation
public static int[][] createSparseMatrixWithPivotColumn(CellLayout iconLayout,
        int pivotX, int pivotY) {

    ViewGroup iconParent = iconLayout.getShortcutsAndWidgets();

    int[][] matrix = createFullMatrix(iconLayout.getCountX() + 1, iconLayout.getCountY());

    // Iterate thru the children of the top parent.
    for (int i = 0; i < iconParent.getChildCount(); i++) {
        View cell = iconParent.getChildAt(i);
        if (!cell.isFocusable()) {
            continue;
        }
        int cx = ((CellLayout.LayoutParams) cell.getLayoutParams()).cellX;
        int cy = ((CellLayout.LayoutParams) cell.getLayoutParams()).cellY;
        if (pivotX < 0) {
            matrix[cx - pivotX][cy] = i;
        } else {
            matrix[cx][cy] = i;
        }
    }

    if (pivotX < 0) {
        matrix[0][pivotY] = PIVOT;
    } else {
        matrix[pivotX][pivotY] = PIVOT;
    }
    return matrix;
}
 

public View onFocusSearchFailed(View focused, int focusDirection, Recycler recycler, State state) {
    resolveShouldLayoutReverse();
    if (getChildCount() == 0) {
        return null;
    }
    int layoutDir = convertFocusDirectionToLayoutDirection(focusDirection);
    if (layoutDir == Integer.MIN_VALUE) {
        return null;
    }
    View referenceChild;
    ensureLayoutState();
    if (layoutDir == -1) {
        referenceChild = findReferenceChildClosestToStart(recycler, state);
    } else {
        referenceChild = findReferenceChildClosestToEnd(recycler, state);
    }
    if (referenceChild == null) {
        return null;
    }
    View nextFocus;
    ensureLayoutState();
    updateLayoutState(layoutDir, (int) (MAX_SCROLL_FACTOR * ((float) this.mOrientationHelper.getTotalSpace())), false, state);
    this.mLayoutState.mScrollingOffset = Integer.MIN_VALUE;
    this.mLayoutState.mRecycle = false;
    fill(recycler, this.mLayoutState, state, true);
    if (layoutDir == -1) {
        nextFocus = getChildClosestToStart();
    } else {
        nextFocus = getChildClosestToEnd();
    }
    if (nextFocus == referenceChild || !nextFocus.isFocusable()) {
        return null;
    }
    return nextFocus;
}
 

protected void fireOnItemClickedEvent(View view, int position) {
    if (position < 0 || position > items.length)
        return;
    I item = items[position];
    carbon.widget.RecyclerView.OnItemClickedListener<I> typeSpecificListener = (carbon.widget.RecyclerView.OnItemClickedListener<I>) onItemClickedListeners.get(item.getClass());
    if (typeSpecificListener != null)
        typeSpecificListener.onItemClicked(view, item, position);
    if (onItemClickedListener != null)
        onItemClickedListener.onItemClicked(view, item, position);
    if (selectionMode != SelectionMode.NONE && view.isFocusable() && view.isClickable())
        selectItem(item);
}
 

@Override
public View onFocusSearchFailed(View focused, int focusDirection,
                                RecyclerView.Recycler recycler,
                                RecyclerView.State state) {
    resolveShouldLayoutReverse();
    if (getChildCount() == 0) {
        return null;
    }

    final int layoutDir = convertFocusDirectionToLayoutDirection(focusDirection);
    if (layoutDir == RenderState.INVALID_LAYOUT) {
        return null;
    }
    final View referenceChild;
    if (layoutDir == RenderState.LAYOUT_START) {
        referenceChild = getChildClosestToStart();
    } else {
        referenceChild = getChildClosestToEnd();
    }
    ensureRenderState();
    final int maxScroll = (int) (MAX_SCROLL_FACTOR * (mOrientationHelper.getEndAfterPadding() -
            mOrientationHelper.getStartAfterPadding()));
    updateRenderState(layoutDir, maxScroll, false, state);
    mRenderState.mScrollingOffset = RenderState.SCOLLING_OFFSET_NaN;
    fill(recycler, mRenderState, state, true);
    final View nextFocus;
    if (layoutDir == RenderState.LAYOUT_START) {
        nextFocus = getChildClosestToStart();
    } else {
        nextFocus = getChildClosestToEnd();
    }
    if (nextFocus == referenceChild || !nextFocus.isFocusable()) {
        return null;
    }
    return nextFocus;
}
 

/**
 * Determines if the supplied {@link View} is actionable for accessibility purposes.
 *
 * @param view The {@link View} to evaluate
 * @return {@code true} if {@code view} is considered actionable for accessibility
 */
public static boolean isActionableForAccessibility(View view) {
  if (view == null) {
    return false;
  }

  return (view.isClickable() || view.isLongClickable() || view.isFocusable());
}
 

/**
 * Focus the given view and show the soft keyboard.
 * @param activity the current activity
 * @param view the view to focus
 */
public static void focusAndShowKeyboard(@Nullable Activity activity, @NonNull View view) {
    if (activity == null) return;
    if (view.isFocusable()) {
        view.requestFocus();
    }
    if (view instanceof EditText) {
        showKeyboard(activity);
    }
}
 

/**
 * @return {@code true} if the given view has a focus.
 */
public static boolean hasFocus(View view) {
    // If the container view is not focusable, we consider it always focused from
    // Chromium's point of view.
    return !view.isFocusable() ? true : view.hasFocus();
}
 

void layoutChunk(RecyclerView.Recycler recycler, RecyclerView.State state,
                 LayoutState layoutState, LayoutChunkResult result) {
    View view = layoutState.next(recycler);
    if (view == null) {
        if (DEBUG && layoutState.mScrapList == null) {
            throw new RuntimeException("received null view when unexpected");
        }
        // if we are laying out views in scrap, this may return null which means there is
        // no more items to layout.
        result.mFinished = true;
        return;
    }
    RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();
    if (layoutState.mScrapList == null) {
        if (mShouldReverseLayout == (layoutState.mLayoutDirection
                == LayoutState.LAYOUT_START)) {
            addView(view);
        } else {
            addView(view, 0);
        }
    } else {
        if (mShouldReverseLayout == (layoutState.mLayoutDirection
                == LayoutState.LAYOUT_START)) {
            addDisappearingView(view);
        } else {
            addDisappearingView(view, 0);
        }
    }
    measureChildWithMargins(view, 0, 0);
    result.mConsumed = mOrientationHelper.getDecoratedMeasurement(view);
    int left, top, right, bottom;
    if (mOrientation == VERTICAL) {
        if (isLayoutRTL()) {
            right = getWidth() - getPaddingRight();
            left = right - mOrientationHelper.getDecoratedMeasurementInOther(view);
        } else {
            left = getPaddingLeft();
            right = left + mOrientationHelper.getDecoratedMeasurementInOther(view);
        }
        if (layoutState.mLayoutDirection == LayoutState.LAYOUT_START) {
            bottom = layoutState.mOffset;
            top = layoutState.mOffset - result.mConsumed;
        } else {
            top = layoutState.mOffset;
            bottom = layoutState.mOffset + result.mConsumed;
        }
    } else {
        top = getPaddingTop();
        bottom = top + mOrientationHelper.getDecoratedMeasurementInOther(view);

        if (layoutState.mLayoutDirection == LayoutState.LAYOUT_START) {
            right = layoutState.mOffset;
            left = layoutState.mOffset - result.mConsumed;
        } else {
            left = layoutState.mOffset;
            right = layoutState.mOffset + result.mConsumed;
        }
    }
    // We calculate everything with View's bounding box (which includes decor and margins)
    // To calculate correct layout position, we subtract margins.
    layoutDecorated(view, left + params.leftMargin, top + params.topMargin,
            right - params.rightMargin, bottom - params.bottomMargin);
    if (DEBUG) {
        Log.d(TAG, "laid out child at position " + getPosition(view) + ", with l:"
                + (left + params.leftMargin) + ", t:" + (top + params.topMargin) + ", r:"
                + (right - params.rightMargin) + ", b:" + (bottom - params.bottomMargin));
    }
    // Consume the available space if the view is not removed OR changed
    if (params.isItemRemoved() || params.isItemChanged()) {
        result.mIgnoreConsumed = true;
    }
    result.mFocusable = view.isFocusable();
}
 

protected void layoutChunk(RecyclerView.Recycler recycler, RecyclerView.State state,
                           LayoutState layoutState, com.alibaba.android.vlayout.layout.LayoutChunkResult result) {
    View view = layoutState.next(recycler);
    if (view == null) {
        if (DEBUG && layoutState.mScrapList == null) {
            throw new RuntimeException("received null view when unexpected");
        }
        // if we are laying out views in scrap, this may return null which means there is
        // no more items to layout.
        result.mFinished = true;
        return;
    }
    RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) view.getLayoutParams();
    if (layoutState.mScrapList == null) {
        // can not find in scrapList
        if (mShouldReverseLayoutExpose == (layoutState.mLayoutDirection
                == LayoutState.LAYOUT_START)) {
            addView(view);
        } else {
            addView(view, 0);
        }
    } else {
        if (mShouldReverseLayoutExpose == (layoutState.mLayoutDirection
                == LayoutState.LAYOUT_START)) {
            addDisappearingView(view);
        } else {
            addDisappearingView(view, 0);
        }
    }
    measureChildWithMargins(view, 0, 0);
    result.mConsumed = mOrientationHelper.getDecoratedMeasurement(view);
    int left, top, right, bottom;
    if (getOrientation() == VERTICAL) {
        if (isLayoutRTL()) {
            right = getWidth() - getPaddingRight();
            left = right - mOrientationHelper.getDecoratedMeasurementInOther(view);
        } else {
            left = getPaddingLeft();
            right = left + mOrientationHelper.getDecoratedMeasurementInOther(view);
        }

        if (layoutState.mLayoutDirection == LayoutState.LAYOUT_START) {
            bottom = layoutState.mOffset;
            top = layoutState.mOffset - result.mConsumed;
        } else {
            top = layoutState.mOffset;
            bottom = layoutState.mOffset + result.mConsumed;
        }
    } else {
        top = getPaddingTop();
        bottom = top + mOrientationHelper.getDecoratedMeasurementInOther(view);

        // whether this layout pass is layout form start to end or in reverse
        if (layoutState.mLayoutDirection == LayoutState.LAYOUT_START) {
            right = layoutState.mOffset;
            left = layoutState.mOffset - result.mConsumed;
        } else {
            left = layoutState.mOffset;
            right = layoutState.mOffset + result.mConsumed;
        }
    }
    // We calculate everything with View's bounding box (which includes decor and margins)
    // To calculate correct layout position, we subtract margins.
    layoutDecorated(view, left + params.leftMargin, top + params.topMargin,
            right - params.rightMargin, bottom - params.bottomMargin);
    if (DEBUG) {
        Log.d(TAG, "laid out child at position " + getPosition(view) + ", with l:"
                + (left + params.leftMargin) + ", t:" + (top + params.topMargin) + ", r:"
                + (right - params.rightMargin) + ", b:" + (bottom - params.bottomMargin));
    }
    // Consume the available space if the view is not removed OR changed
    if (params.isItemRemoved() || params.isItemChanged()) {
        result.mIgnoreConsumed = true;
    }
    result.mFocusable = view.isFocusable();
}
 

@Override
public View onFocusSearchFailed(View focused, int focusDirection,
                                RecyclerView.Recycler recycler, RecyclerView.State state) {
    myResolveShouldLayoutReverse();
    if (getChildCount() == 0) {
        return null;
    }

    final int layoutDir = convertFocusDirectionToLayoutDirectionExpose(focusDirection);
    if (layoutDir == LayoutState.INVALID_LAYOUT) {
        return null;
    }

    View referenceChild = null;
    if (layoutDir == LayoutState.LAYOUT_START) {
        referenceChild = myFindReferenceChildClosestToStart(state);
    } else {
        referenceChild = myFindReferenceChildClosestToEnd(state);

    }

    if (referenceChild == null) {
        if (DEBUG) {
            Log.d(TAG,
                    "Cannot find a child with a valid position to be used for focus search.");
        }
        return null;
    }
    ensureLayoutStateExpose();
    final int maxScroll = (int) (MAX_SCROLL_FACTOR * mOrientationHelper.getTotalSpace());
    updateLayoutStateExpose(layoutDir, maxScroll, false, state);
    mLayoutState.mScrollingOffset = LayoutState.SCOLLING_OFFSET_NaN;
    mLayoutState.mRecycle = false;
    mLayoutState.mOnRefresLayout = false;
    fill(recycler, mLayoutState, state, true);
    final View nextFocus;
    if (layoutDir == LayoutState.LAYOUT_START) {
        nextFocus = getChildClosestToStartExpose();
    } else {
        nextFocus = getChildClosestToEndExpose();
    }
    if (nextFocus == referenceChild || !nextFocus.isFocusable()) {
        return null;
    }
    return nextFocus;
}
 

@Override
public boolean matchesSafely(View view) {
  return view.isFocusable() == isFocusable;
}
 

void layoutChunk(Recycler recycler, State state, LayoutState layoutState, LayoutChunkResult result) {
    View view = layoutState.next(recycler);
    if (view == null) {
        result.mFinished = true;
        return;
    }
    int right;
    int left;
    int bottom;
    int top;
    LayoutParams params = (LayoutParams) view.getLayoutParams();
    if (layoutState.mScrapList == null) {
        if (this.mShouldReverseLayout == (layoutState.mLayoutDirection == -1)) {
            addView(view);
        } else {
            addView(view, 0);
        }
    } else {
        if (this.mShouldReverseLayout == (layoutState.mLayoutDirection == -1)) {
            addDisappearingView(view);
        } else {
            addDisappearingView(view, 0);
        }
    }
    measureChildWithMargins(view, 0, 0);
    result.mConsumed = this.mOrientationHelper.getDecoratedMeasurement(view);
    if (this.mOrientation == 1) {
        if (isLayoutRTL()) {
            right = getWidth() - getPaddingRight();
            left = right - this.mOrientationHelper.getDecoratedMeasurementInOther(view);
        } else {
            left = getPaddingLeft();
            right = left + this.mOrientationHelper.getDecoratedMeasurementInOther(view);
        }
        if (layoutState.mLayoutDirection == -1) {
            bottom = layoutState.mOffset;
            top = layoutState.mOffset - result.mConsumed;
        } else {
            top = layoutState.mOffset;
            bottom = layoutState.mOffset + result.mConsumed;
        }
    } else {
        top = getPaddingTop();
        bottom = top + this.mOrientationHelper.getDecoratedMeasurementInOther(view);
        if (layoutState.mLayoutDirection == -1) {
            right = layoutState.mOffset;
            left = layoutState.mOffset - result.mConsumed;
        } else {
            left = layoutState.mOffset;
            right = layoutState.mOffset + result.mConsumed;
        }
    }
    layoutDecorated(view, left + params.leftMargin, top + params.topMargin, right - params.rightMargin, bottom - params.bottomMargin);
    if (params.isItemRemoved() || params.isItemChanged()) {
        result.mIgnoreConsumed = true;
    }
    result.mFocusable = view.isFocusable();
}