use*_*691 82 android scrollview
我ScrollView在Android中使用了一个,其中可见部分的ScrollView大小与其中一个单元格的大小相同Scrollview.每个"细胞"都是相同的高度.因此,我想要做的是ScrollView在滚动后捕捉到位置.
目前我正在检测用户何时触摸,ScrollView以及何时开始滚动并从那里开始工作,但它非常错误.当用户只是轻弹它并滚动然后减速时,它也需要工作.
在iPhone上有一个类似的功能,didDecelerate在ScrollView完成滚动后我可以做任何我想要的代码.Android有这样的东西吗？或者是否有一些我可以看到的代码来找出更好的方法呢？
我查看了Android文档,找不到类似的东西.
tul*_*84z 93
我最近不得不实现你描述的功能.我做的是让一个Runnable检查出ScrollView是否已经停止滚动,当首次使用在变量newCheck定义的时间之后返回的值触发onTouchEvent时,比较getScrollY()返回的值.
见下面的代码(工作解决方案):
public class MyScrollView extends ScrollView{
private Runnable scrollerTask;
private int initialPosition;
private int newCheck = 100;
private static final String TAG = "MyScrollView";
public interface OnScrollStoppedListener{
void onScrollStopped();
}
private OnScrollStoppedListener onScrollStoppedListener;
public MyScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
scrollerTask = new Runnable() {
public void run() {
int newPosition = getScrollY();
if(initialPosition - newPosition == 0){//has stopped
if(onScrollStoppedListener!=null){
onScrollStoppedListener.onScrollStopped();
}
}else{
initialPosition = getScrollY();
MyScrollView.this.postDelayed(scrollerTask, newCheck);
}
}
};
}
public void setOnScrollStoppedListener(MyScrollView.OnScrollStoppedListener listener){
onScrollStoppedListener = listener;
}
public void startScrollerTask(){
initialPosition = getScrollY();
MyScrollView.this.postDelayed(scrollerTask, newCheck);
}
}
然后我有:
scroll.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
scroll.startScrollerTask();
}
return false;
}
});
scroll.setOnScrollStoppedListener(new OnScrollStoppedListener() {
public void onScrollStopped() {
Log.i(TAG, "stopped");
}
});
顺便说一下,我用其他回复中的一些想法在我的应用程序中执行此操作.希望这可以帮助.有任何问题请随时询问我(们).干杯.
con*_*ept 22
这是另一个修复,恕我直言,在ScrollView中缺少OnEndScroll事件错误.
它的灵感来自于朴实的答案.只需将此类放入您的项目(更改包以匹配您自己的)并使用下面的xml
package com.thecrag.components.ui;
import android.content.Context;
import android.util.AttributeSet;
import android.widget.ScrollView;
public class ResponsiveScrollView extends ScrollView {
public interface OnEndScrollListener {
public void onEndScroll();
}
private boolean mIsFling;
private OnEndScrollListener mOnEndScrollListener;
public ResponsiveScrollView(Context context) {
this(context, null, 0);
}
public ResponsiveScrollView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public ResponsiveScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
public void fling(int velocityY) {
super.fling(velocityY);
mIsFling = true;
}
@Override
protected void onScrollChanged(int x, int y, int oldX, int oldY) {
super.onScrollChanged(x, y, oldX, oldY);
if (mIsFling) {
if (Math.abs(y - oldY) < 2 || y >= getMeasuredHeight() || y == 0) {
if (mOnEndScrollListener != null) {
mOnEndScrollListener.onEndScroll();
}
mIsFling = false;
}
}
}
public OnEndScrollListener getOnEndScrollListener() {
return mOnEndScrollListener;
}
public void setOnEndScrollListener(OnEndScrollListener mOnEndScrollListener) {
this.mOnEndScrollListener = mOnEndScrollListener;
}
}
再次更改包名称以匹配您的项目
<com.thecrag.components.ui.ResponsiveScrollView
android:id="@+id/welcome_scroller"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/welcome_scroll_command_help_container"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/welcome_header_text_thecrag"
android:layout_margin="6dp">
....
</com.thecrag.components.ui.ResponsiveScrollView>
我将(水平)ScrollView子类化并做了类似这样的事情:
@Override
protected void onScrollChanged(int x, int y, int oldX, int oldY) {
if (Math.abs(x - oldX) > SlowDownThreshold) {
currentlyScrolling = true;
} else {
currentlyScrolling = false;
if (!currentlyTouching) {
//scrolling stopped...handle here
}
}
super.onScrollChanged(x, y, oldX, oldY);
}
我为SlowDownThreshold使用值1,因为它似乎总是最后一次onScrollChanged事件的差异.
为了在慢慢拖动时使其行为正常,我必须这样做:
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
currentlyTouching = true;
}
return super.onInterceptTouchEvent(event);
}
@Override
public boolean onTouch(View view, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
currentlyTouching = false;
if (!currentlyScrolling) {
//I handle the release from a drag here
return true;
}
}
return false;
}
我的方法是每次调用onScrollChanged()时通过更改时间戳来确定滚动状态.可以很容易地确定滚动的开始和结束时间.您还可以更改阈值(我使用100毫秒)来修复灵敏度.
public class CustomScrollView extends ScrollView {
private long lastScrollUpdate = -1;
private class ScrollStateHandler implements Runnable {
@Override
public void run() {
long currentTime = System.currentTimeMillis();
if ((currentTime - lastScrollUpdate) > 100) {
lastScrollUpdate = -1;
onScrollEnd();
} else {
postDelayed(this, 100);
}
}
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (lastScrollUpdate == -1) {
onScrollStart();
postDelayed(new ScrollStateHandler(), 100);
}
lastScrollUpdate = System.currentTimeMillis();
}
private void onScrollStart() {
// do something
}
private void onScrollEnd() {
// do something
}
}
小智 5
我对这个问题的方法是使用计时器来检查以下 2 个“事件”。
1) onScrollChanged() 停止被调用
2）用户的手指从滚动视图中抬起
public class CustomScrollView extends HorizontalScrollView {
public CustomScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
Timer ntimer = new Timer();
MotionEvent event;
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt)
{
checkAgain();
super.onScrollChanged(l, t, oldl, oldt);
}
public void checkAgain(){
try{
ntimer.cancel();
ntimer.purge();
}
catch(Exception e){}
ntimer = new Timer();
ntimer.schedule(new TimerTask() {
@Override
public void run() {
if(event.getAction() == MotionEvent.ACTION_UP){
// ScrollView Stopped Scrolling and Finger is not on the ScrollView
}
else{
// ScrollView Stopped Scrolling But Finger is still on the ScrollView
checkAgain();
}
}
},100);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
this.event = event;
return super.onTouchEvent(event);
}
}
在我看来，这是又一个简单而干净的解决方案，它自然受到上述答案的启发。基本上，在短暂延迟（此处为50ms）之后，用户结束手势后，检查getScrollY（）是否仍在更改。
public class ScrollViewWithOnStopListener extends ScrollView {
OnScrollStopListener listener;
public interface OnScrollStopListener {
void onScrollStopped(int y);
}
public ScrollViewWithOnStopListener(Context context) {
super(context);
}
public ScrollViewWithOnStopListener(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_UP:
checkIfScrollStopped();
}
return super.onTouchEvent(ev);
}
int initialY = 0;
private void checkIfScrollStopped() {
initialY = getScrollY();
this.postDelayed(new Runnable() {
@Override
public void run() {
int updatedY = getScrollY();
if (updatedY == initialY) {
//we've stopped
if (listener != null) {
listener.onScrollStopped(getScrollY());
}
} else {
initialY = updatedY;
checkIfScrollStopped();
}
}
}, 50);
}
public void setOnScrollStoppedListener(OnScrollStopListener yListener) {
listener = yListener;
}
}
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