在不在活动中的片段中的ListView项上滑动删除

Question

我的目标是通过在片段中滑动来删除列表视图项。在这里我试图删除右侧的呼叫历史

我关注OnFling in a ListView, Get the swiped Item info

“但我总是在onFling方法中获得 MotionEvent e1 null（MotionEvent e1，MotionEvent e2）”

最后我开始知道它在MainActivity中有效，然后我在下面的链接中找到它

https://github.com/romannurik/Android-SwipeToDismiss

在这里，我要正确删除项目，但我的问题是“刷卡不会发生。这意味着如果我刷了10次，那就是2到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();
}

}