下面列出了android.view.View#FOCUS_RIGHT 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
@Override
public boolean dispatchUnhandledMove(View focused, int direction) {
// XXX-RTL: This will be fixed in a future CL
if (direction == View.FOCUS_LEFT) {
if (getCurrentPage() > 0) {
snapToPage(getCurrentPage() - 1);
return true;
}
} else if (direction == View.FOCUS_RIGHT) {
if (getCurrentPage() < getPageCount() - 1) {
snapToPage(getCurrentPage() + 1);
return true;
}
}
return super.dispatchUnhandledMove(focused, direction);
}
/**
* <p>Handles scrolling in response to a "page up/down" shortcut press. This
* method will scroll the view by one page left or right and give the focus
* to the leftmost/rightmost component in the new visible area. If no
* component is a good candidate for focus, this scrollview reclaims the
* focus.</p>
*
* @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT}
* to go one page left or {@link android.view.View#FOCUS_RIGHT}
* to go one page right
* @return true if the key event is consumed by this method, false otherwise
*/
public boolean pageScroll(int direction) {
boolean right = direction == View.FOCUS_RIGHT;
int width = getWidth();
if (right) {
mTempRect.left = getScrollX() + width;
int count = getChildCount();
if (count > 0) {
View view = getChildAt(0);
if (mTempRect.left + width > view.getRight()) {
mTempRect.left = view.getRight() - width;
}
}
} else {
mTempRect.left = getScrollX() - width;
if (mTempRect.left < 0) {
mTempRect.left = 0;
}
}
mTempRect.right = mTempRect.left + width;
return scrollAndFocus(direction, mTempRect.left, mTempRect.right);
}
/**
* <p>Handles scrolling in response to a "home/end" shortcut press. This
* method will scroll the view to the left or right and give the focus
* to the leftmost/rightmost component in the new visible area. If no
* component is a good candidate for focus, this scrollview reclaims the
* focus.</p>
*
* @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT}
* to go the left of the view or {@link android.view.View#FOCUS_RIGHT}
* to go the right
* @return true if the key event is consumed by this method, false otherwise
*/
public boolean fullScroll(int direction) {
boolean right = direction == View.FOCUS_RIGHT;
int width = getWidth();
mTempRect.left = 0;
mTempRect.right = width;
if (right) {
int count = getChildCount();
if (count > 0) {
View view = getChildAt(0);
mTempRect.right = view.getRight();
mTempRect.left = mTempRect.right - width;
}
}
return scrollAndFocus(direction, mTempRect.left, mTempRect.right);
}
public boolean fullScrollH(int direction) {
boolean right = direction == View.FOCUS_RIGHT;
int width = getWidth();
mTempRect.left = 0;
mTempRect.right = width;
if (right) {
int count = getChildCount();
if (count > 0) {
View view = getChildAt(0);
mTempRect.right = view.getRight();
mTempRect.left = mTempRect.right - width;
}
}
return scrollAndFocusH(direction, mTempRect.left, mTempRect.right);
}
private int getMovement(int direction) {
if (mOrientation == VERTICAL) {
if (direction == View.FOCUS_UP) {
return mShouldReverseLayout ? DIRECTION_FORWARD : DIRECTION_BACKWARD;
} else if (direction == View.FOCUS_DOWN) {
return mShouldReverseLayout ? DIRECTION_BACKWARD : DIRECTION_FORWARD;
} else {
return DIRECTION_NO_WHERE;
}
} else {
if (direction == View.FOCUS_LEFT) {
return mShouldReverseLayout ? DIRECTION_FORWARD : DIRECTION_BACKWARD;
} else if (direction == View.FOCUS_RIGHT) {
return mShouldReverseLayout ? DIRECTION_BACKWARD : DIRECTION_FORWARD;
} else {
return DIRECTION_NO_WHERE;
}
}
}
@Override
public boolean dispatchUnhandledMove(View focused, int direction) {
if (super.dispatchUnhandledMove(focused, direction)) {
return true;
}
if (mIsRtl) {
if (direction == View.FOCUS_LEFT) {
direction = View.FOCUS_RIGHT;
} else if (direction == View.FOCUS_RIGHT) {
direction = View.FOCUS_LEFT;
}
}
if (direction == View.FOCUS_LEFT) {
if (getCurrentPage() > 0) {
snapToPage(getCurrentPage() - 1);
return true;
}
} else if (direction == View.FOCUS_RIGHT) {
if (getCurrentPage() < getPageCount() - 1) {
snapToPage(getCurrentPage() + 1);
return true;
}
}
return false;
}
@Override
public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
if (getDescendantFocusability() == FOCUS_BLOCK_DESCENDANTS) {
return;
}
// XXX-RTL: This will be fixed in a future CL
if (mCurrentPage >= 0 && mCurrentPage < getPageCount()) {
getPageAt(mCurrentPage).addFocusables(views, direction, focusableMode);
}
if (direction == View.FOCUS_LEFT) {
if (mCurrentPage > 0) {
getPageAt(mCurrentPage - 1).addFocusables(views, direction, focusableMode);
}
} else if (direction == View.FOCUS_RIGHT){
if (mCurrentPage < getPageCount() - 1) {
getPageAt(mCurrentPage + 1).addFocusables(views, direction, focusableMode);
}
}
}
@Override
public boolean dispatchUnhandledMove(View focused, int direction) {
// XXX-RTL: This will be fixed in a future CL
if (direction == View.FOCUS_LEFT) {
if (getCurrentPage() > 0) {
snapToPage(getCurrentPage() - 1);
return true;
}
} else if (direction == View.FOCUS_RIGHT) {
if (getCurrentPage() < getPageCount() - 1) {
snapToPage(getCurrentPage() + 1);
return true;
}
}
return super.dispatchUnhandledMove(focused, direction);
}
@Override
public void handleKeyboardEvent(KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
int direction;
switch (event.getKeyCode()) {
case KeyEvent.KEYCODE_DPAD_DOWN:
direction = View.FOCUS_DOWN;
break;
case KeyEvent.KEYCODE_DPAD_UP:
direction = View.FOCUS_UP;
break;
case KeyEvent.KEYCODE_DPAD_LEFT:
direction = View.FOCUS_LEFT;
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
direction = View.FOCUS_RIGHT;
break;
default:
direction = 0;
break;
}
if (direction != 0 && tryToMoveFocus(direction)) return;
}
mContentsClient.onUnhandledKeyEvent(event);
}
/**
* Converts a focusDirection to orientation.
*
* @param focusDirection One of {@link View#FOCUS_UP}, {@link View#FOCUS_DOWN},
* {@link View#FOCUS_LEFT}, {@link View#FOCUS_RIGHT},
* {@link View#FOCUS_BACKWARD}, {@link View#FOCUS_FORWARD}
* or 0 for not applicable
* @return {@link LayoutState#LAYOUT_START} or {@link LayoutState#LAYOUT_END} if focus direction
* is applicable to current state, {@link LayoutState#INVALID_LAYOUT} otherwise.
*/
private int convertFocusDirectionToLayoutDirection(int focusDirection) {
switch (focusDirection) {
case View.FOCUS_BACKWARD:
if (mOrientation == VERTICAL) {
return LayoutState.LAYOUT_START;
} else if (isLayoutRTL()) {
return LayoutState.LAYOUT_END;
} else {
return LayoutState.LAYOUT_START;
}
case View.FOCUS_FORWARD:
if (mOrientation == VERTICAL) {
return LayoutState.LAYOUT_END;
} else if (isLayoutRTL()) {
return LayoutState.LAYOUT_START;
} else {
return LayoutState.LAYOUT_END;
}
case View.FOCUS_UP:
return mOrientation == VERTICAL ? LayoutState.LAYOUT_START
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_DOWN:
return mOrientation == VERTICAL ? LayoutState.LAYOUT_END
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_LEFT:
return mOrientation == HORIZONTAL ? LayoutState.LAYOUT_START
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_RIGHT:
return mOrientation == HORIZONTAL ? LayoutState.LAYOUT_END
: LayoutState.INVALID_LAYOUT;
default:
if (DEBUG) {
Log.d(TAG, "Unknown focus request:" + focusDirection);
}
return LayoutState.INVALID_LAYOUT;
}
}
@Override
public boolean dispatchUnhandledMove(View focused, int direction) {
if (direction == View.FOCUS_LEFT) {
if (getCurrentPage() > 0) {
snapToPage(getCurrentPage() - 1);
return true;
}
} else if (direction == View.FOCUS_RIGHT) {
if (getCurrentPage() < getChildCount() - 1) {
snapToPage(getCurrentPage() + 1);
return true;
}
}
return super.dispatchUnhandledMove(focused, direction);
}
/**
* Converts a focusDirection to orientation.
*
* @param focusDirection One of {@link View#FOCUS_UP}, {@link View#FOCUS_DOWN},
* {@link View#FOCUS_LEFT}, {@link View#FOCUS_RIGHT},
* {@link View#FOCUS_BACKWARD}, {@link View#FOCUS_FORWARD}
* or 0 for not applicable
* @return {@link RenderState#LAYOUT_START} or {@link RenderState#LAYOUT_END} if focus direction
* is applicable to current state, {@link RenderState#INVALID_LAYOUT} otherwise.
*/
private int convertFocusDirectionToLayoutDirection(int focusDirection) {
switch (focusDirection) {
case View.FOCUS_BACKWARD:
return RenderState.LAYOUT_START;
case View.FOCUS_FORWARD:
return RenderState.LAYOUT_END;
case View.FOCUS_UP:
return mOrientation == VERTICAL ? RenderState.LAYOUT_START
: RenderState.INVALID_LAYOUT;
case View.FOCUS_DOWN:
return mOrientation == VERTICAL ? RenderState.LAYOUT_END
: RenderState.INVALID_LAYOUT;
case View.FOCUS_LEFT:
return mOrientation == HORIZONTAL ? RenderState.LAYOUT_START
: RenderState.INVALID_LAYOUT;
case View.FOCUS_RIGHT:
return mOrientation == HORIZONTAL ? RenderState.LAYOUT_END
: RenderState.INVALID_LAYOUT;
default:
if (DEBUG) {
Log.d(TAG, "Unknown focus request:" + focusDirection);
}
return RenderState.INVALID_LAYOUT;
}
}
/**
* Converts a focusDirection to orientation.
*
* @param focusDirection One of {@link View#FOCUS_UP}, {@link View#FOCUS_DOWN},
* {@link View#FOCUS_LEFT}, {@link View#FOCUS_RIGHT},
* {@link View#FOCUS_BACKWARD}, {@link View#FOCUS_FORWARD}
* or 0 for not applicable
* @return {@link LayoutState#LAYOUT_START} or {@link LayoutState#LAYOUT_END} if focus direction
* is applicable to current state, {@link LayoutState#INVALID_LAYOUT} otherwise.
*/
private int convertFocusDirectionToLayoutDirection(int focusDirection) {
switch (focusDirection) {
case View.FOCUS_BACKWARD:
return LayoutState.LAYOUT_START;
case View.FOCUS_FORWARD:
return LayoutState.LAYOUT_END;
case View.FOCUS_UP:
return mOrientation == VERTICAL ? LayoutState.LAYOUT_START
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_DOWN:
return mOrientation == VERTICAL ? LayoutState.LAYOUT_END
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_LEFT:
return mOrientation == HORIZONTAL ? LayoutState.LAYOUT_START
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_RIGHT:
return mOrientation == HORIZONTAL ? LayoutState.LAYOUT_END
: LayoutState.INVALID_LAYOUT;
default:
if (DEBUG) {
Log.d(TAG, "Unknown focus request:" + focusDirection);
}
return LayoutState.INVALID_LAYOUT;
}
}
public boolean arrowScroll(int direction) {
View currentFocused = findFocus();
if (currentFocused == this) currentFocused = null;
boolean handled = false;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused,
direction);
if (nextFocused != null && nextFocused != currentFocused) {
if (direction == View.FOCUS_LEFT) {
// If there is nothing to the left, or this is causing us to
// jump to the right, then what we really want to do is page left.
if (currentFocused != null && nextFocused.getLeft() >= currentFocused.getLeft()) {
handled = pageLeft();
} else {
handled = nextFocused.requestFocus();
}
} else if (direction == View.FOCUS_RIGHT) {
// If there is nothing to the right, or this is causing us to
// jump to the left, then what we really want to do is page right.
if (currentFocused != null && nextFocused.getLeft() <= currentFocused.getLeft()) {
handled = pageRight();
} else {
handled = nextFocused.requestFocus();
}
}
} else if (direction == FOCUS_LEFT || direction == FOCUS_BACKWARD) {
// Trying to move left and nothing there; try to page.
handled = pageLeft();
} else if (direction == FOCUS_RIGHT || direction == FOCUS_FORWARD) {
// Trying to move right and nothing there; try to page.
handled = pageRight();
}
if (handled) {
playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
}
return handled;
}
/**
* Converts a focusDirection to orientation.
*
* @param focusDirection One of {@link View#FOCUS_UP}, {@link View#FOCUS_DOWN},
* {@link View#FOCUS_LEFT}, {@link View#FOCUS_RIGHT},
* {@link View#FOCUS_BACKWARD}, {@link View#FOCUS_FORWARD}
* or 0 for not applicable
* @return {@link LayoutState#LAYOUT_START} or {@link LayoutState#LAYOUT_END} if focus direction
* is applicable to current state, {@link LayoutState#INVALID_LAYOUT} otherwise.
*/
int convertFocusDirectionToLayoutDirection(int focusDirection) {
switch (focusDirection) {
case View.FOCUS_BACKWARD:
if (mOrientation == VERTICAL) {
return LayoutState.LAYOUT_START;
} else if (isLayoutRTL()) {
return LayoutState.LAYOUT_END;
} else {
return LayoutState.LAYOUT_START;
}
case View.FOCUS_FORWARD:
if (mOrientation == VERTICAL) {
return LayoutState.LAYOUT_END;
} else if (isLayoutRTL()) {
return LayoutState.LAYOUT_START;
} else {
return LayoutState.LAYOUT_END;
}
case View.FOCUS_UP:
return mOrientation == VERTICAL ? LayoutState.LAYOUT_START
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_DOWN:
return mOrientation == VERTICAL ? LayoutState.LAYOUT_END
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_LEFT:
return mOrientation == HORIZONTAL ? LayoutState.LAYOUT_START
: LayoutState.INVALID_LAYOUT;
case View.FOCUS_RIGHT:
return mOrientation == HORIZONTAL ? LayoutState.LAYOUT_END
: LayoutState.INVALID_LAYOUT;
default:
if (DEBUG) {
Log.d(TAG, "Unknown focus request:" + focusDirection);
}
return LayoutState.INVALID_LAYOUT;
}
}
/**
* What is the distance between the source and destination rectangles given the direction of
* focus navigation between them? The direction basically helps figure out more quickly what is
* self evident by the relationship between the rects...
*
* @param source the source rectangle
* @param dest the destination rectangle
* @param direction the direction
* @return the distance between the rectangles
*/
static int getDistance(Rect source, Rect dest, int direction) {
int sX, sY; // source x, y
int dX, dY; // dest x, y
switch (direction) {
case View.FOCUS_RIGHT:
sX = source.right;
sY = source.top + source.height() / 2;
dX = dest.left;
dY = dest.top + dest.height() / 2;
break;
case View.FOCUS_DOWN:
sX = source.left + source.width() / 2;
sY = source.bottom;
dX = dest.left + dest.width() / 2;
dY = dest.top;
break;
case View.FOCUS_LEFT:
sX = source.left;
sY = source.top + source.height() / 2;
dX = dest.right;
dY = dest.top + dest.height() / 2;
break;
case View.FOCUS_UP:
sX = source.left + source.width() / 2;
sY = source.top;
dX = dest.left + dest.width() / 2;
dY = dest.bottom;
break;
default:
throw new IllegalArgumentException("direction must be one of "
+ "{FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT}.");
}
int deltaX = dX - sX;
int deltaY = dY - sY;
return deltaY * deltaY + deltaX * deltaX;
}
public boolean arrowScroll(int direction) {
View currentFocused = findFocus();
if (currentFocused == this) currentFocused = null;
boolean handled = false;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused,
direction);
if (nextFocused != null && nextFocused != currentFocused) {
if (direction == View.FOCUS_LEFT) {
handled = nextFocused.requestFocus();
} else if (direction == View.FOCUS_RIGHT) {
// If there is nothing to the right, or this is causing us to
// jump to the left, then what we really want to do is page right.
if (currentFocused != null && nextFocused.getLeft() <= currentFocused.getLeft()) {
handled = pageRight();
} else {
handled = nextFocused.requestFocus();
}
}
} else if (direction == FOCUS_LEFT || direction == FOCUS_BACKWARD) {
// Trying to move left and nothing there; try to page.
handled = pageLeft();
} else if (direction == FOCUS_RIGHT || direction == FOCUS_FORWARD) {
// Trying to move right and nothing there; try to page.
handled = pageRight();
}
if (handled) {
playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
}
return handled;
}
@Override
public boolean takeFocus(boolean reverse) {
int direction =
(reverse == (mContainerView.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL)) ?
View.FOCUS_RIGHT : View.FOCUS_LEFT;
if (tryToMoveFocus(direction)) return true;
direction = reverse ? View.FOCUS_UP : View.FOCUS_DOWN;
return tryToMoveFocus(direction);
}
/**
* When looking for focus in children of a scroll view, need to be a little
* more careful not to give focus to something that is scrolled off screen.
*
* This is more expensive than the default {@link android.view.ViewGroup}
* implementation, otherwise this behavior might have been made the default.
*/
@Override
protected boolean onRequestFocusInDescendants(int direction,
Rect previouslyFocusedRect) {
// convert from forward / backward notation to up / down / left / right
// (ugh).
if (direction == View.FOCUS_FORWARD) {
direction = View.FOCUS_RIGHT;
} else if (direction == View.FOCUS_BACKWARD) {
direction = View.FOCUS_LEFT;
}
final View nextFocus = previouslyFocusedRect == null ?
FocusFinder.getInstance().findNextFocus(this, null, direction) :
FocusFinder.getInstance().findNextFocusFromRect(this,
previouslyFocusedRect, direction);
if (nextFocus == null) {
return false;
}
if (isOffScreen(nextFocus)) {
return false;
}
return nextFocus.requestFocus(direction, previouslyFocusedRect);
}
public boolean arrowScroll(int direction) {
View currentFocused = findFocus();
if (currentFocused == this) currentFocused = null;
boolean handled = false;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused,
direction);
if (nextFocused != null && nextFocused != currentFocused) {
if (direction == View.FOCUS_LEFT) {
handled = nextFocused.requestFocus();
} else if (direction == View.FOCUS_RIGHT) {
// If there is nothing to the right, or this is causing us to
// jump to the left, then what we really want to do is page right.
if (currentFocused != null && nextFocused.getLeft() <= currentFocused.getLeft()) {
handled = pageRight();
} else {
handled = nextFocused.requestFocus();
}
}
} else if (direction == FOCUS_LEFT || direction == FOCUS_BACKWARD) {
// Trying to move left and nothing there; try to page.
handled = pageLeft();
} else if (direction == FOCUS_RIGHT || direction == FOCUS_FORWARD) {
// Trying to move right and nothing there; try to page.
handled = pageRight();
}
if (handled) {
playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
}
return handled;
}