Java Code Examples for android.widget.ListView.getFirstVisiblePosition()

private void updatePodcastRows() {
    ListView list = getListView();
    int first = list.getFirstVisiblePosition();
    int last = list.getLastVisiblePosition();
    for (int i = first; i <= last; i++) {
        View view = list.getChildAt(i - first);
        list.getAdapter().getView(i, view, list);
    }
}
 

static void scrollListBy(ListView listView, int y) {
    int firstPosition = listView.getFirstVisiblePosition();
    if (firstPosition != -1) {
        View firstView = listView.getChildAt(0);
        if (firstView != null) {
            listView.setSelectionFromTop(firstPosition, firstView.getTop() - y);
        }
    }
}
 

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    // Shortcuts that work no matter what is selected
    if (QMail.useVolumeKeysForListNavigationEnabled() &&
            (keyCode == KeyEvent.KEYCODE_VOLUME_UP ||
            keyCode == KeyEvent.KEYCODE_VOLUME_DOWN)) {

        final ListView listView = getListView();

        int currentPosition = listView.getSelectedItemPosition();
        if (currentPosition == AdapterView.INVALID_POSITION || listView.isInTouchMode()) {
            currentPosition = listView.getFirstVisiblePosition();
        }

        if (keyCode == KeyEvent.KEYCODE_VOLUME_UP && currentPosition > 0) {
            listView.setSelection(currentPosition - 1);
        } else if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN &&
                currentPosition < listView.getCount()) {
            listView.setSelection(currentPosition + 1);
        }

        return true;
    }

    return super.onKeyDown(keyCode, event);
}
 

/**
 * 局部更新API
 */
public void notifyItemChanged(ListView listview, int position){
    int firstPos = listview.getFirstVisiblePosition();
    int lastPos = listview.getLastVisiblePosition();
    Job job = mData.get(position);
    if(position >= firstPos && position <= lastPos){
        View view = listview.getChildAt(position - firstPos); //NOTE
        DownloadAdapter.VH vh = (DownloadAdapter.VH) view.getTag();
        vh.progress.setProgress(job.progress);
        if(job.progress == 100){
            vh.btn.setText("完成");
        }
    }
}
 

/**
 * @see <a href="http://stackoverflow.com/questions/24811536/android-listview-get-item-view-by-position" >android - listview get item view by position
</a>
 * @param pos
 * @param listView
 * @return
 */
public static View getViewByPosition(int pos, ListView listView) {
    final int firstListItemPosition = listView.getFirstVisiblePosition();
    final int lastListItemPosition = firstListItemPosition + listView.getChildCount() - 1;

    if (pos < firstListItemPosition || pos > lastListItemPosition ) {
        return listView.getAdapter().getView(pos, null, listView);
    } else {
        final int childIndex = pos - firstListItemPosition;
        return listView.getChildAt(childIndex);
    }
}
 

/**
 * Notifies the menu that the contents of the menu item specified by {@code menuRowId} have
 * changed.  This should be called if icons, titles, etc. are changing for a particular menu
 * item while the menu is open.
 * @param menuRowId The id of the menu item to change.  This must be a row id and not a child
 *                  id.
 */
public void menuItemContentChanged(int menuRowId) {
    // Make sure we have all the valid state objects we need.
    if (mAdapter == null || mMenu == null || mPopup == null || mPopup.getListView() == null) {
        return;
    }

    // Calculate the item index.
    int index = -1;
    int menuSize = mMenu.size();
    for (int i = 0; i < menuSize; i++) {
        if (mMenu.getItem(i).getItemId() == menuRowId) {
            index = i;
            break;
        }
    }
    if (index == -1) return;

    // Check if the item is visible.
    ListView list = mPopup.getListView();
    int startIndex = list.getFirstVisiblePosition();
    int endIndex = list.getLastVisiblePosition();
    if (index < startIndex || index > endIndex) return;

    // Grab the correct View.
    View view = list.getChildAt(index - startIndex);
    if (view == null) return;

    // Cause the Adapter to re-populate the View.
    list.getAdapter().getView(index, view, list);
}
 

public boolean canTargetScrollVertically(int direction) {
    ListView target = this.mTarget;
    int itemCount = target.getCount();
    if (itemCount == 0) {
        return false;
    }
    int childCount = target.getChildCount();
    int firstPosition = target.getFirstVisiblePosition();
    int lastPosition = firstPosition + childCount;
    if (direction > 0) {
        if (lastPosition >= itemCount && target.getChildAt(childCount - 1).getBottom() <= target.getHeight()) {
            return false;
        }
    } else if (direction >= 0) {
        return false;
    } else {
        if (firstPosition <= 0 && target.getChildAt(0).getTop() >= 0) {
            return false;
        }
    }
    return true;
}
 

/**
 * 单个更新某个条目   只有可见的时候更新progress，
 * @param progress 当前进度
 * @param position 位置
 * @param lv_message Listview
    */
public static void updateProgressPartly(int progress,int position,ListView lv_message){
	int firstVisiblePosition = lv_message.getFirstVisiblePosition();
	int lastVisiblePosition = lv_message.getLastVisiblePosition();
	if(position>=firstVisiblePosition && position<=lastVisiblePosition){
		View view = lv_message.getChildAt(position - firstVisiblePosition);
		if(view.getTag() instanceof ImageMessageHolder){
			ImageMessageHolder vh = (ImageMessageHolder)view.getTag();
			vh.sobot_pic_progress_round.setProgress(progress);
		}
	}
}
 

public boolean canTargetScrollVertically(int direction) {
    ListView target = this.mTarget;
    int itemCount = target.getCount();
    if (itemCount == 0) {
        return false;
    }
    int childCount = target.getChildCount();
    int firstPosition = target.getFirstVisiblePosition();
    int lastPosition = firstPosition + childCount;
    if (direction > 0) {
        if (lastPosition >= itemCount && target.getChildAt(childCount - 1).getBottom() <= target.getHeight()) {
            return false;
        }
    } else if (direction >= 0) {
        return false;
    } else {
        if (firstPosition <= 0 && target.getChildAt(0).getTop() >= 0) {
            return false;
        }
    }
    return true;
}
 

private View getViewByPosition(int pos, ListView listView) {
    final int firstListItemPosition = listView.getFirstVisiblePosition();
    final int lastListItemPosition = firstListItemPosition + listView.getChildCount() - 1;

    if (pos < firstListItemPosition || pos > lastListItemPosition ) {
        return listView.getAdapter().getView(pos, null, listView);
    } else {
        final int childIndex = pos - firstListItemPosition;
        return listView.getChildAt(childIndex);
    }
}
 

/**
 * Utility method to check whether a {@link ListView} can scroll up from it's current position.
 * Handles platform version differences, providing backwards compatible functionality where
 * needed.
 */
private static boolean canListViewScrollUp(ListView listView) {
    if (android.os.Build.VERSION.SDK_INT >= 14) {
        // For ICS and above we can call canScrollVertically() to determine this
        return ViewCompat.canScrollVertically(listView, -1);
    } else {
        // Pre-ICS we need to manually check the first visible item and the child view's top
        // value
        return listView.getChildCount() > 0 &&
                (listView.getFirstVisiblePosition() > 0
                        || listView.getChildAt(0).getTop() < listView.getPaddingTop());
    }
}
 

@Override
    public AnimatorUpdateListener onLoadingFinish(final RefreshKernel kernel, final int footerHeight, int startDelay, final int duration) {
        if (mScrollableView != null && kernel.getRefreshLayout().isEnableScrollContentWhenLoaded()) {
            if (!canScrollDown(mScrollableView)) {
                return null;
            }
            if (mScrollableView instanceof AbsListView && !(mScrollableView instanceof ListView) && Build.VERSION.SDK_INT < 19) {
                if (startDelay > 0) {
                    kernel.getRefreshLayout().getLayout().postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            ((AbsListView) mScrollableView).smoothScrollBy(footerHeight, duration);
                        }
                    }, startDelay);
                } else {
                    ((AbsListView) mScrollableView).smoothScrollBy(footerHeight, duration);
                }
                return null;
            }
            return new AnimatorUpdateListener() {
                int lastValue = kernel.getSpinner();
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    int value = (int) animation.getAnimatedValue();
                    try {
                        if (mScrollableView instanceof ListView) {
                            if (Build.VERSION.SDK_INT >= 19) {
                                ((ListView) RefreshContentWrapper.this.mScrollableView).scrollListBy(value - lastValue);
                            } else {
//                                ListViewCompat.scrollListBy((ListView) mScrollableView, value - lastValue);
                                ListView listView = (ListView) RefreshContentWrapper.this.mScrollableView;
                                final int firstPosition = listView.getFirstVisiblePosition();
                                if (firstPosition == ListView.INVALID_POSITION) {
                                    return;
                                }
                                final View firstView = listView.getChildAt(0);
                                if (firstView == null) {
                                    return;
                                }
                                final int newTop = firstView.getTop() - (value - lastValue);
                                listView.setSelectionFromTop(firstPosition, newTop);
                            }
                        } else {
                            mScrollableView.scrollBy(0, value - lastValue);
                        }
                    } catch (Throwable ignored) {
                        //根据用户反馈，此处可能会有BUG
                    }
                    lastValue = value;
                }
            };
        }
        return null;
    }
 

@Override
    public AnimatorUpdateListener onLoadingFinish(final RefreshKernel kernel, final int footerHeight, int startDelay, final int duration) {
        if (mScrollableView != null && kernel.getRefreshLayout().isEnableScrollContentWhenLoaded()) {
            if (!canScrollDown(mScrollableView)) {
                return null;
            }
            if (mScrollableView instanceof AbsListView && !(mScrollableView instanceof ListView) && Build.VERSION.SDK_INT < 19) {
                if (startDelay > 0) {
                    kernel.getRefreshLayout().getLayout().postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            ((AbsListView) mScrollableView).smoothScrollBy(footerHeight, duration);
                        }
                    }, startDelay);
                } else {
                    ((AbsListView) mScrollableView).smoothScrollBy(footerHeight, duration);
                }
                return null;
            }
            return new AnimatorUpdateListener() {
                int lastValue = kernel.getSpinner();
                @Override
                public void onAnimationUpdate(ValueAnimator animation) {
                    int value = (int) animation.getAnimatedValue();
                    try {
                        if (mScrollableView instanceof ListView) {
                            if (Build.VERSION.SDK_INT >= 19) {
                                ((ListView) RefreshContentWrapper.this.mScrollableView).scrollListBy(value - lastValue);
                            } else {
//                                ListViewCompat.scrollListBy((ListView) mScrollableView, value - lastValue);
                                ListView listView = (ListView) RefreshContentWrapper.this.mScrollableView;
                                final int firstPosition = listView.getFirstVisiblePosition();
                                if (firstPosition == ListView.INVALID_POSITION) {
                                    return;
                                }
                                final View firstView = listView.getChildAt(0);
                                if (firstView == null) {
                                    return;
                                }
                                final int newTop = firstView.getTop() - (value - lastValue);
                                listView.setSelectionFromTop(firstPosition, newTop);
                            }
                        } else {
                            mScrollableView.scrollBy(0, value - lastValue);
                        }
                    } catch (Throwable ignored) {
                        //根据用户反馈，此处可能会有BUG
                    }
                    lastValue = value;
                }
            };
        }
        return null;
    }
 

/**
 * listview滚动到顶部
 *
 * @param animate 是否动画
 * @return
 */
public UDBaseListOrRecyclerView scrollToTop(final int offset, final boolean animate) {
    final ListView lv = getListView();
    if (lv != null) {
        if (animate) {
            if (lv.getFirstVisiblePosition() > 7) {//hack fast scroll
                lv.setSelection(7);
            }
            lv.smoothScrollToPositionFromTop(0, offset);
        } else {
            lv.setSelectionFromTop(0, offset);
        }
    }
    return this;
}
 

public static boolean isIdVisible(ListView listView, long id) {
    final int firstVisible = listView.getFirstVisiblePosition();
    final int lastVisible = listView.getLastVisiblePosition();

    for (int pos = firstVisible; pos <= lastVisible; pos++) {
        long posId = listView.getItemIdAtPosition(pos);

        if (posId == id) {
            return true;
        }
    }

    return false;
}
 

private int getScroll() {
	ListView listview = basePagedItemAdapter.getListView();
	View c = listview.getChildAt(0); //this is the first visible row
	int scrollY = -c.getTop();
	listViewItemHeights.put(listview.getFirstVisiblePosition(), c.getHeight());
	for (int i = 0; i < listview.getFirstVisiblePosition(); i ++) {
		if (listViewItemHeights.get(i) != null) { // (this is a sanity check)
			scrollY += listViewItemHeights.get(i); //add all heights of the views that are gone
		}
	}
	return scrollY;
}
 

public void saveListPosition() {
    if (mAdapter != null) {
        ListView l = getListView();
        int position = l.getFirstVisiblePosition();
        View v = l.getChildAt(0);
        int top = (v == null) ? 0 : v.getTop();
        setListPosition(new Position(position, top));
    }
}
 

void onWordListClicked(final View v) {
    // Note : v is the preference view
    final ViewParent parent = v.getParent();
    // Just in case something changed in the framework, test for the concrete class
    if (!(parent instanceof ListView)) return;
    final ListView listView = (ListView)parent;
    final int indexToOpen;
    // Close all first, we'll open back any item that needs to be open.
    final boolean wasOpen = mInterfaceState.isOpen(mWordlistId);
    mInterfaceState.closeAll();
    if (wasOpen) {
        // This button being shown. Take note that we don't want to open any button in the
        // loop below.
        indexToOpen = -1;
    } else {
        // This button was not being shown. Open it, and remember the index of this
        // child as the one to open in the following loop.
        mInterfaceState.setOpen(mWordlistId, mStatus);
        indexToOpen = listView.indexOfChild(v);
    }
    final int lastDisplayedIndex =
            listView.getLastVisiblePosition() - listView.getFirstVisiblePosition();
    // The "lastDisplayedIndex" is actually displayed, hence the <=
    for (int i = 0; i <= lastDisplayedIndex; ++i) {
        final ButtonSwitcher buttonSwitcher = (ButtonSwitcher)listView.getChildAt(i)
                .findViewById(R.id.wordlist_button_switcher);
        if (i == indexToOpen) {
            buttonSwitcher.setStatusAndUpdateVisuals(getButtonSwitcherStatus(mStatus));
        } else {
            buttonSwitcher.setStatusAndUpdateVisuals(ButtonSwitcher.STATUS_NO_BUTTON);
        }
    }
}
 

private boolean isRowInIconLoadingRange(long id) {
    ListView list = getListView();
    int count = adapter.getCount();
    int first = list.getFirstVisiblePosition();
    int last = list.getLastVisiblePosition();
    int visible = last - first + 1;
    int start = Math.max(0, first - visible / 2);
    int end = Math.min(count - 1, last + visible / 2);
    for (int i = start; i <= end; i++) {
        if (id == adapter.getItemId(i)) {
            return true;
        }
    }
    return false;
}
 

private void updatePodcastRow(long id) {
    ListView list = getListView();
    int first = list.getFirstVisiblePosition();
    int last = list.getLastVisiblePosition();
    for (int i = first; i <= last; i++) {
        if (id == list.getItemIdAtPosition(i)) {
            View view = list.getChildAt(i - first);
            list.getAdapter().getView(i, view, list);
            break;
        }
    }
}