我的目标是通过在片段中滑动来删除列表视图项。这里我试图删除右侧的通话记录
我在 ListView 中关注 OnFling，获取已刷过的项目信息
“但我总是在 onFling(MotionEvent e1, MotionEvent e2) 方法中得到 MotionEvent e1 null”
最后我才知道它在 MainActivity 中有效，然后我按照下面的链接来获取它
https://github.com/romannurik/Android-SwipeToDismiss
在这里我要正确删除项目，但我的问题是“刷卡不是经常发生。意味着如果我刷了 10 次，它会增加 2 或 3 次”
这是我在DialerFragment.java中的代码
final SwipeDismissListViewTouchListener swipeDismissTouchListener;
swipeDismissTouchListener = new SwipeDismissListViewTouchListener(listView,
new SwipeDismissListViewTouchListener.DismissCallbacks() {
public boolean canDismiss(int position) {
return true;
}
public void onDismiss(ListView listView, int[] reverseSortedPositions) {
long[] selectedIds = null;
/*
* Code to delete
*/
}
});
listView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
return swipeDismissTouchListener.onTouch(view, motionEvent);
}
});
listView.setOnScrollListener(swipeDismissTouchListener.makeScrollListener());
和另一个类SwipeDismissListViewTouchListener.java
public class SwipeDismissListViewTouchListener implements View.OnTouchListener {
// Cached ViewConfiguration and system-wide constant values
private int mSlop;
private int mMinFlingVelocity;
private int mMaxFlingVelocity;
private long mAnimationTime;
// Fixed properties
private ListView mListView;
private DismissCallbacks mCallbacks;
private int mViewWidth = 1; // 1 and not 0 to prevent dividing by zero
// Transient properties
private List<PendingDismissData> mPendingDismisses = new ArrayList<PendingDismissData>();
private int mDismissAnimationRefCount = 0;
private float mDownX;
private boolean mSwiping;
private VelocityTracker mVelocityTracker;
private int mDownPosition;
private View mDownView;
private boolean mPaused;
/**
* The callback interface used by {@link SwipeDismissListViewTouchListener} to inform its client
* about a successful dismissal of one or more list item positions.
*/
public interface DismissCallbacks {
/**
* Called to determine whether the given position can be dismissed.
*/
boolean canDismiss(int position);
/**
* Called when the user has indicated they she would like to dismiss one or more list item
* positions.
*
* @param listView The originating {@link ListView}.
* @param reverseSortedPositions An array of positions to dismiss, sorted in descending
* order for convenience.
*/
void onDismiss(ListView listView, int[] reverseSortedPositions);
}
/**
* Constructs a new swipe-to-dismiss touch listener for the given list view.
*
* @param listView The list view whose items should be dismissable.
* @param callbacks The callback to trigger when the user has indicated that she would like to
* dismiss one or more list items.
*/
public SwipeDismissListViewTouchListener(ListView listView, DismissCallbacks callbacks) {
ViewConfiguration vc = ViewConfiguration.get(listView.getContext());
mSlop = vc.getScaledTouchSlop();
mMinFlingVelocity = vc.getScaledMinimumFlingVelocity() * 16;
mMaxFlingVelocity = vc.getScaledMaximumFlingVelocity();
mAnimationTime = listView.getContext().getResources().getInteger(
android.R.integer.config_shortAnimTime);
mListView = listView;
mCallbacks = callbacks;
}
/**
* Enables or disables (pauses or resumes) watching for swipe-to-dismiss gestures.
*
* @param enabled Whether or not to watch for gestures.
*/
public void setEnabled(boolean enabled) {
mPaused = !enabled;
}
/**
* Returns an {@link AbsListView.OnScrollListener} to be added to the {@link
* ListView} using {@link ListView#setOnScrollListener(AbsListView.OnScrollListener)}.
* If a scroll listener is already assigned, the caller should still pass scroll changes through
* to this listener. This will ensure that this {@link SwipeDismissListViewTouchListener} is
* paused during list view scrolling.</p>
*
* @see SwipeDismissListViewTouchListener
*/
public AbsListView.OnScrollListener makeScrollListener() {
return new AbsListView.OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView absListView, int scrollState) {
setEnabled(scrollState != AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL);
}
@Override
public void onScroll(AbsListView absListView, int i, int i1, int i2) {
}
};
}
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
if (mViewWidth < 2) {
mViewWidth = mListView.getWidth();
}
switch (motionEvent.getActionMasked()) {
case MotionEvent.ACTION_DOWN: {
if (mPaused) {
return false;
}
// TODO: ensure this is a finger, and set a flag
// Find the child view that was touched (perform a hit test)
Rect rect = new Rect();
int childCount = mListView.getChildCount();
int[] listViewCoords = new int[2];
mListView.getLocationOnScreen(listViewCoords);
int x = (int) motionEvent.getRawX() - listViewCoords[0];
int y = (int) motionEvent.getRawY() - listViewCoords[1];
View child;
for (int i = 0; i < childCount; i++) {
child = mListView.getChildAt(i);
child.getHitRect(rect);
if (rect.contains(x, y)) {
mDownView = child;
break;
}
}
if (mDownView != null) {
mDownX = motionEvent.getRawX();
mDownPosition = mListView.getPositionForView(mDownView);
if (mCallbacks.canDismiss(mDownPosition)) {
mVelocityTracker = VelocityTracker.obtain();
mVelocityTracker.addMovement(motionEvent);
} else {
mDownView = null;
}
}
view.onTouchEvent(motionEvent);
return true;
}
case MotionEvent.ACTION_UP: {
if (mVelocityTracker == null) {
break;
}
float deltaX = motionEvent.getRawX() - mDownX;
mVelocityTracker.addMovement(motionEvent);
mVelocityTracker.computeCurrentVelocity(1000);
float velocityX = mVelocityTracker.getXVelocity();
float absVelocityX = Math.abs(velocityX);
float absVelocityY = Math.abs(mVelocityTracker.getYVelocity());
boolean dismiss = false;
boolean dismissRight = false;
if (Math.abs(deltaX) > mViewWidth / 2) {
dismiss = true;
dismissRight = deltaX > 0;
} else if (mMinFlingVelocity <= absVelocityX && absVelocityX <= mMaxFlingVelocity
&& absVelocityY < absVelocityX) {
// dismiss only if flinging in the same direction as dragging
dismiss = (velocityX < 0) == (deltaX < 0);
dismissRight = mVelocityTracker.getXVelocity() > 0;
}
if (dismiss) {
// dismiss
final View downView = mDownView; // mDownView gets null'd before animation ends
final int downPosition = mDownPosition;
++mDismissAnimationRefCount;
mDownView.animate()
.translationX(dismissRight ? mViewWidth : -mViewWidth)
.alpha(0)
.setDuration(mAnimationTime)
.setListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
performDismiss(downView, downPosition);
}
});
} else {
// cancel
mDownView.animate()
.translationX(0)
.alpha(1)
.setDuration(mAnimationTime)
.setListener(null);
}
mVelocityTracker.recycle();
mVelocityTracker = null;
mDownX = 0;
mDownView = null;
mDownPosition = ListView.INVALID_POSITION;
mSwiping = false;
break;
}
case MotionEvent.ACTION_MOVE: {
if (mVelocityTracker == null || mPaused) {
break;
}
mVelocityTracker.addMovement(motionEvent);
float deltaX = motionEvent.getRawX() - mDownX;
if (Math.abs(deltaX) > mSlop) {
mSwiping = true;
mListView.requestDisallowInterceptTouchEvent(true);
// Cancel ListView's touch (un-highlighting the item)
MotionEvent cancelEvent = MotionEvent.obtain(motionEvent);
cancelEvent.setAction(MotionEvent.ACTION_CANCEL |
(motionEvent.getActionIndex()
<< MotionEvent.ACTION_POINTER_INDEX_SHIFT));
mListView.onTouchEvent(cancelEvent);
cancelEvent.recycle();
}
if (mSwiping) {
mDownView.setTranslationX(deltaX);
mDownView.setAlpha(Math.max(0f, Math.min(1f,
1f - 2f * Math.abs(deltaX) / mViewWidth)));
return true;
}
break;
}
}
return false;
}
class PendingDismissData implements Comparable<PendingDismissData> {
public int position;
public View view;
public PendingDismissData(int position, View view) {
this.position = position;
this.view = view;
}
@Override
public int compareTo(PendingDismissData other) {
// Sort by descending position
return other.position - position;
}
}
private void performDismiss(final View dismissView, final int dismissPosition) {
// Animate the dismissed list item to zero-height and fire the dismiss callback when
// all dismissed list item animations have completed. This triggers layout on each animation
// frame; in the future we may want to do something smarter and more performant.
final ViewGroup.LayoutParams lp = dismissView.getLayoutParams();
final int originalHeight = dismissView.getHeight();
ValueAnimator animator = ValueAnimator.ofInt(originalHeight, 1).setDuration(mAnimationTime);
animator.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
--mDismissAnimationRefCount;
if (mDismissAnimationRefCount == 0) {
// No active animations, process all pending dismisses.
// Sort by descending position
Collections.sort(mPendingDismisses);
int[] dismissPositions = new int[mPendingDismisses.size()];
for (int i = mPendingDismisses.size() - 1; i >= 0; i--) {
dismissPositions[i] = mPendingDismisses.get(i).position;
}
mCallbacks.onDismiss(mListView, dismissPositions);
ViewGroup.LayoutParams lp;
for (PendingDismissData pendingDismiss : mPendingDismisses) {
// Reset view presentation
pendingDismiss.view.setAlpha(1f);
pendingDismiss.view.setTranslationX(0);
lp = pendingDismiss.view.getLayoutParams();
lp.height = originalHeight;
pendingDismiss.view.setLayoutParams(lp);
}
mPendingDismisses.clear();
}
}
});
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
lp.height = (Integer) valueAnimator.getAnimatedValue();
dismissView.setLayoutParams(lp);
}
});
mPendingDismisses.add(new PendingDismissData(dismissPosition, dismissView));
animator.start();
}
}