Android 获取滚动视图垂直滚动方向
欢迎各位 我有scrollview,我想知道滚动方向是向上还是向下 因为我想在滚动到底部时隐藏actionbar选项卡(如twitter应用程序) 试过了,但没用Android 获取滚动视图垂直滚动方向,android,Android,欢迎各位 我有scrollview,我想知道滚动方向是向上还是向下 因为我想在滚动到底部时隐藏actionbar选项卡(如twitter应用程序) 试过了,但没用 wrap_layout.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { switch (ev
wrap_layout.setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
y = event.getY();
break;
case MotionEvent.ACTION_UP:
Log.d("scroll", event.getY() - y + "");
break;
default:
break;
}
return false;
}
});
最简单的方法是创建这样的自定义滚动视图
public class ObservableScrollView extends ScrollView{
public ObservableScrollView(Context context) {
super(context);
}
public ObservableScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ObservableScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
}
然后遍历onScrollChanged()方法
@覆盖
受保护的无效onScrollChanged(int-scrollX、int-scrollY、int-oldScrollX、int-oldScrollY){
super.onScrollChanged(scrollX、scrollY、oldScrollX、oldScrollY);
如果(滚动创建自定义滚动视图
public class CustomScrollView extends ScrollView {
private float mTouchPosition;
private float mReleasePosition;
public interface OnScrollViewListener {
void onScrollChanged(CustomScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY);
void scrollUp();
void scrollDown();
}
private OnScrollViewListener mOnScrollViewListener;
public CustomScrollView(Context context) {
this(context, null, 0);
}
public CustomScrollView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
mOnScrollViewListener.onScrollChanged( this, l, t, oldl, oldt );
super.onScrollChanged(l, t, oldl, oldt);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
mTouchPosition = event.getY();
}
if (event.getAction() == MotionEvent.ACTION_UP) {
mReleasePosition = event.getY();
if (mTouchPosition - mReleasePosition > 0) {
mOnScrollViewListener.scrollDown();
} else {
mOnScrollViewListener.scrollUp();
}
}
return super.onTouchEvent(event);
}
public void setOnScrollViewListener(OnScrollViewListener l) {
this.mOnScrollViewListener = l;
}
}
并添加监听器
yourCustomScrollView.setOnScrollViewListener(new CustomScrollView.OnScrollViewListener() {
@Override
public void onScrollChanged(CustomScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
}
@Override
public void scrollUp() {
Timber.e("SCROLL UP");
}
@Override
public void scrollDown() {
Timber.e("SCROLL DOWN");
}
});
您只需将ScrollListener设置为scrollView,并按如下方式处理它
nsv.setOnScrollChangeListener((NestedScrollView.OnScrollChangeListener) (v, scrollX, scrollY, oldScrollX, oldScrollY) -> {
if (!nsv.canScrollVertically(1))
{
// bottom of scroll view
}
//reached at top of scrollView
if (!nsv.canScrollVertically(-1)) {
// top of scroll view
}
//scrolling up and down
if(scrollY<oldScrollY){
//vertical scrolling down
}else{
//vertical scrolling upp
}
if(scrollX<oldScrollX){
//horizontal scrolling down
}else{
//horizontal scrolling upp
}});
nsv.setOnScrollChangeListener((NestedScrollView.OnScrollChangeListener)(v,scrollX,scrollY,oldScrollX,oldScrollY)->{
如果(!nsv.cans)(1))
{
//滚动视图的底部
}
//到达滚动视图的顶部
如果(!nsv.cans(-1)){
//滚动视图顶部
}
//上下滚动
如果(滚动)只存储当前的y偏移,如果发生滚动,则获取差异。如果y偏移发生变化,则垂直滚动。首先,我尝试知道垂直方向(上/下)如果是垂直或水平秒,则不会。已经尝试过了,但不起作用。在滚动时,您可以从滚动视图中获取当前的y偏移量吗?如果是这样,如果您采用difference=currentOffsetY-oldOffsetY
且该值为正值,则为正值(我相信是向下的),如果为负数,则向上。请参阅我在上面添加的代码。我发现oldScrollY在牛轧糖上始终返回0。在下一个作用域向上时,我能够跟踪旧滚动。
nsv.setOnScrollChangeListener((NestedScrollView.OnScrollChangeListener) (v, scrollX, scrollY, oldScrollX, oldScrollY) -> {
if (!nsv.canScrollVertically(1))
{
// bottom of scroll view
}
//reached at top of scrollView
if (!nsv.canScrollVertically(-1)) {
// top of scroll view
}
//scrolling up and down
if(scrollY<oldScrollY){
//vertical scrolling down
}else{
//vertical scrolling upp
}
if(scrollX<oldScrollX){
//horizontal scrolling down
}else{
//horizontal scrolling upp
}});