Java Code Examples for android.widget.ListView#getLastVisiblePosition()

public static void ensureVisible(@Nullable ListView listView, int pos) {
    if (listView == null || listView.getAdapter() == null) {
        return;
    }

    if (pos < 0 || pos >= listView.getAdapter().getCount()) {
        return;
    }

    int first = listView.getFirstVisiblePosition();
    int last = listView.getLastVisiblePosition();

    if (pos < first) {
        listView.setSelection(pos);
        return;
    }

    if (pos >= last) {
        listView.setSelection(1 + pos - (last - first));
    }
}
 

public static RowViewInfo getCurrentRowViewInfo(FileListViewFragment host, Object item)
{
    if(host == null || host.isRemoving() || !host.isResumed())
        return null;
    ListView list = host.getListView();
    if(list == null)
        return null;
    int start = list.getFirstVisiblePosition();
    for(int i=start, j=list.getLastVisiblePosition();i<=j;i++)
        if(j<list.getCount() && item == list.getItemAtPosition(i))
        {
            RowViewInfo rvi = new RowViewInfo();
            rvi.view = list.getChildAt(i-start);
            rvi.position = i;
            rvi.listView = list;
            return rvi;
        }
    return null;
}
 

public void selectItem(int num) {
	final ListView commitList = (ListView) getView().findViewById(R.id.git_history_commit_list);
	
	selectedItem = num;
	int selection = num - commitList.getFirstVisiblePosition();
	
	//Keep the selected commit on screen... with a little bit of breathing room
	if (num < commitList.getFirstVisiblePosition() + 2) {
		commitList.setSelection(num == 0 ? num : num - 1);
	} else if (num > commitList.getLastVisiblePosition() - 2) {
		commitList.setSelection(num == commitList.getCount() - 1 ? num : num + 1);
	}
	
	for (int i = 0; i < commitList.getCount(); i ++) {
		View child = commitList.getChildAt(i);
		
		if (child != null) {
			child.setBackgroundColor(selection == i
					? getResources().getColor(R.color.holo_select)
					: getResources().getColor(android.R.color.transparent));
		}
	}
}
 

private void onMsgRecv(MessageEntity entity) {
    logger.d("message_activity#onMsgRecv");

    imService.getUnReadMsgManager().ackReadMsg(entity);
    logger.d("chat#start pushList");
    pushList(entity);
    ListView lv = lvPTR.getRefreshableView();
    if (lv != null) {

        if (lv.getLastVisiblePosition() < adapter.getCount()) {
            textView_new_msg_tip.setVisibility(View.VISIBLE);
        } else {
            scrollToBottomListItem();
        }
    }
}
 

/**
 * 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 static Object getViewHolderByIndex(ListView listView, int index) {
    int firstVisibleFeedPosition = listView.getFirstVisiblePosition() - listView.getHeaderViewsCount();
    int lastVisibleFeedPosition = listView.getLastVisiblePosition() - listView.getHeaderViewsCount();

    //只有获取可见区域的
    if (index >= firstVisibleFeedPosition && index <= lastVisibleFeedPosition) {
        View view = listView.getChildAt(index - firstVisibleFeedPosition);
        Object tag = view.getTag();
        return tag;
    } else {
        return null;
    }
}
 

public static boolean isLastMessageVisible(ListView messageListView) {
    if (messageListView == null || messageListView.getAdapter() == null) {
        return false;
    }

    if (messageListView.getLastVisiblePosition() >= messageListView.getAdapter().getCount() - 1 - messageListView.getFooterViewsCount()) {
        return true;
    } else {
        return false;
    }
}
 

@Override
public void onItemCheckedStateChanged(ActionMode mode, int position, long id, boolean checked) {
    ListView listView = getListView();
    int count = listView.getCheckedItemCount();
    mode.setTitle(getResources().getQuantityString(R.plurals.itemsSelected, count, count));
    // Update (redraw) list item view
    int start = listView.getFirstVisiblePosition();
    for (int i = start, j = listView.getLastVisiblePosition(); i <= j; i++) {
        if (position == i) {
            View view = listView.getChildAt(i - start);
            listView.getAdapter().getView(i, view, listView);
            break;
        }
    }
}
 

@Override
public void onSaveInstanceState(@NonNull final Bundle outState) {
	super.onSaveInstanceState(outState);

	// Save the last log list view scroll position
	final ListView list = getListView();
	final boolean scrolledToBottom = list.getCount() > 0 && list.getLastVisiblePosition() == list.getCount() - 1;
	outState.putInt(SIS_LOG_SCROLL_POSITION, scrolledToBottom ? LOG_SCROLLED_TO_BOTTOM : list.getFirstVisiblePosition());
}
 

/**
 * 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);
}
 

private ScrollState getScrollPosition() {
    final ListView listView = this.binding == null ? null : this.binding.messagesView;
    if (listView == null || listView.getCount() == 0 || listView.getLastVisiblePosition() == listView.getCount() - 1) {
        return null;
    } else {
        final int pos = listView.getFirstVisiblePosition();
        final View view = listView.getChildAt(0);
        if (view == null) {
            return null;
        } else {
            return new ScrollState(pos, view.getTop());
        }
    }
}
 

private boolean hasHitBottom() {
    if (mMainView instanceof ScrollView) {
        ScrollView scrollView = (ScrollView) mMainView;
        View view = scrollView.getChildAt(scrollView.getChildCount() - 1);
        int diff = (view.getBottom() - (scrollView.getHeight() + scrollView.getScrollY()));// Calculate the scrolldiff
        return diff == 0;
    } else if (mMainView instanceof ListView) {
        ListView listView = (ListView) mMainView;
        if (listView.getAdapter() != null) {
            if (listView.getAdapter().getCount() > 0) {
                return listView.getLastVisiblePosition() == listView.getAdapter().getCount() - 1 &&
                        listView.getChildAt(listView.getChildCount() - 1).getBottom() <= listView.getHeight();
            }
        }
    } else if (mMainView instanceof RecyclerView) {
        RecyclerView recyclerView = (RecyclerView) mMainView;
        if (recyclerView.getAdapter() != null && recyclerView.getLayoutManager() != null) {
            RecyclerView.Adapter adapter = recyclerView.getAdapter();
            if (adapter.getItemCount() > 0) {
                RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
                if (layoutManager instanceof LinearLayoutManager) {
                    LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
                    return linearLayoutManager.findLastCompletelyVisibleItemPosition() == adapter.getItemCount() - 1;
                } else if (layoutManager instanceof StaggeredGridLayoutManager) {
                    StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
                    int[] checks = staggeredGridLayoutManager.findLastCompletelyVisibleItemPositions(null);
                    for (int check : checks) {
                        if (check == adapter.getItemCount() - 1)
                            return true;
                    }
                }
            }
        }
    }
    return false;
}
 

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);
        }
    }
}
 

/**
 * 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);
}
 

/**
 * 判断 ListView 是否已经滚动到底部
 *
 * @param listView 需要被判断的 ListView
 * @return
 */
public static boolean isListViewAlreadyAtBottom(ListView listView) {
    if (listView.getAdapter() == null || listView.getHeight() == 0) {
        return false;
    }

    if (listView.getLastVisiblePosition() == listView.getAdapter().getCount() - 1) {
        View lastItemView = listView.getChildAt(listView.getChildCount() - 1);
        if (lastItemView != null && lastItemView.getBottom() == listView.getHeight()) {
            return true;
        }
    }
    return false;
}
 

public static void smoothScrollToPositionCompat(ListView listView,
                                                int position, int offset) {
    if (android.os.Build.VERSION.SDK_INT >= 11) {
        listView.smoothScrollToPositionFromTop(position, offset);
    }
    {
        int firstVisible = listView.getFirstVisiblePosition();
        int lastVisible = listView.getLastVisiblePosition();
        if (position < firstVisible)
            listView.smoothScrollToPosition(position);
        else
            listView.smoothScrollToPosition(position + lastVisible
                    - firstVisible - 2);
    }
}
 

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 void updateRowView(ListView lv, int pos)
{
    int start = lv.getFirstVisiblePosition();
    if(pos >= start && pos <= lv.getLastVisiblePosition())
    {
        View view = lv.getChildAt(pos - start);
        lv.getAdapter().getView(pos, view, lv);
    }
}
 

/**
 * 判断 ListView 是否已经滚动到底部
 *
 * @param listView 需要被判断的 ListView
 * @return
 */
public static boolean isListViewAlreadyAtBottom(ListView listView) {
    if (listView.getAdapter() == null || listView.getHeight() == 0) {
        return false;
    }

    if (listView.getLastVisiblePosition() == listView.getAdapter().getCount() - 1) {
        View lastItemView = listView.getChildAt(listView.getChildCount() - 1);
        if (lastItemView != null && lastItemView.getBottom() == listView.getHeight()) {
            return true;
        }
    }
    return false;
}
 

@Override
boolean isShownInList(ListView list, int pos) {
    return pos >= list.getFirstVisiblePosition() && pos <= list.getLastVisiblePosition();
}