android.util.SparseBooleanArray#keyAt ( )源码实例Demo

/**
 * <p>Applies the columns collapse status to a new row added to this
 * table. This method is invoked by PassThroughHierarchyChangeListener
 * upon child insertion.</p>
 *
 * <p>This method only applies to {@link android.widget.TableRow}
 * instances.</p>
 *
 * @param child the newly added child
 */
private void trackCollapsedColumns(View child) {
    if (child instanceof TableRow) {
        final TableRow row = (TableRow) child;
        final SparseBooleanArray collapsedColumns = mCollapsedColumns;
        final int count = collapsedColumns.size();
        for (int i = 0; i < count; i++) {
            int columnIndex = collapsedColumns.keyAt(i);
            boolean isCollapsed = collapsedColumns.valueAt(i);
            // the collapse status is set only when the column should be
            // collapsed; otherwise, this might affect the default
            // visibility of the row's children
            if (isCollapsed) {
                row.setColumnCollapsed(columnIndex, isCollapsed);
            }
        }
    }
}
 

/**
 * Use this when an item has been deleted, to move the check state of all following items up one
 * step. If you have a choiceMode which is not none, this method must be called when the order of
 * items changes in an underlying adapter which does not have stable IDs (see {@link
 * android.widget.ListAdapter#hasStableIds()}). This is because without IDs, the ListView has no
 * way of knowing which items have moved where, and cannot update the check state accordingly.
 * <p/>
 * See also further comments on {@link #moveCheckState(int, int)}.
 *
 * @param position
 */
public void removeCheckState(int position) {
  SparseBooleanArray cip = getCheckedItemPositions();

  if (cip.size() == 0) {
    return;
  }
  int[] runStart = new int[cip.size()];
  int[] runEnd = new int[cip.size()];
  int rangeStart = position;
  int rangeEnd = cip.keyAt(cip.size() - 1) + 1;
  int runCount = buildRunList(cip, rangeStart, rangeEnd, runStart, runEnd);
  for (int i = 0; i != runCount; i++) {
    if (! (runStart[i] == position || (runEnd[i] < runStart[i] && runEnd[i] > position))) {
      // Only set a new check mark in front of this run if it does
      // not contain the deleted position. If it does, we only need
      // to make it one check mark shorter at the end.
      setItemChecked(rotate(runStart[i], - 1, rangeStart, rangeEnd), true);
    }
    setItemChecked(rotate(runEnd[i], - 1, rangeStart, rangeEnd), false);
  }
}
 

private int[] getSelectedIndices(ListView listView) {
    SparseBooleanArray sparseArray = listView.getCheckedItemPositions();
    int selectedCount = 0;
    for (int i = 0; i < sparseArray.size(); ++i) {
        if (sparseArray.valueAt(i)) {
            selectedCount++;
        }
    }
    int[] indices = new int[selectedCount];
    for (int i = 0, j = 0; i < sparseArray.size(); ++i) {
        if (sparseArray.valueAt(i)) {
            indices[j++] = sparseArray.keyAt(i);
        }
    }
    return indices;
}
 

/**
 * Use this when an item has been deleted, to move the check state of all
 * following items up one step. If you have a choiceMode which is not none,
 * this method must be called when the order of items changes in an
 * underlying adapter which does not have stable IDs (see
 * {@link ListAdapter#hasStableIds()}). This is because without IDs, the
 * ListView has no way of knowing which items have moved where, and cannot
 * updateCache the check state accordingly.
 * 
 * See also further comments on {@link #moveCheckState(int, int)}.
 * 
 * @param position
 */
public void removeCheckState(int position) {
    SparseBooleanArray cip = getCheckedItemPositions();

    if (cip.size() == 0)
        return;
    int[] runStart = new int[cip.size()];
    int[] runEnd = new int[cip.size()];
    int rangeEnd = cip.keyAt(cip.size() - 1) + 1;
    int runCount = buildRunList(cip, position, rangeEnd, runStart, runEnd);
    for (int i = 0; i != runCount; i++) {
        if (!(runStart[i] == position || (runEnd[i] < runStart[i] && runEnd[i] > position))) {
            // Only set a new check mark in front of this run if it does
            // not contain the deleted position. If it does, we only need
            // to make it one check mark shorter at the end.
            setItemChecked(rotate(runStart[i], -1, position, rangeEnd), true);
        }
        setItemChecked(rotate(runEnd[i], -1, position, rangeEnd), false);
    }
}
 

private static int[] getSelectedIndices(ListView listView) {
    SparseBooleanArray sparseArray = listView.getCheckedItemPositions();
    int selectedCount = 0;
    for (int i = 0; i < sparseArray.size(); ++i) {
        if (sparseArray.valueAt(i)) {
            selectedCount++;
        }
    }
    int[] indices = new int[selectedCount];
    for (int i = 0, j = 0; i < sparseArray.size(); ++i) {
        if (sparseArray.valueAt(i)) {
            indices[j++] = sparseArray.keyAt(i);
        }
    }
    return indices;
}
 

private void cleanUpArrayForUser(SparseBooleanArray array, int removedUserId) {
    for (int i = array.size() - 1; i >= 0; i--) {
        final int uid = array.keyAt(i);
        final int userId = UserHandle.getUserId(uid);

        if (userId == removedUserId) {
            array.removeAt(i);
        }
    }
}
 

protected void deleteSelectedItems() {
    SparseBooleanArray checkedItems = getListView().getCheckedItemPositions();
    for (int i = checkedItems.size() - 1; i > -1; --i) {
        int position = checkedItems.keyAt(i);
        boolean checked = checkedItems.get(position);
        if (checked) {
            getDescriptorList().remove(position);
        }
     }
}
 

private void uncheckAllItems() {
    if( listView == null ) {
        return;
    }
    SparseBooleanArray checked = listView.getCheckedItemPositions();
    for (int i = 0; i < checked.size(); i++) {
        // Item position in adapter
        int position = checked.keyAt(i);
        // Add sport if it is checked i.e.) == TRUE!
        if (checked.valueAt(i)) {
            listView.setItemChecked(position, false);
        }
    }
}
 

private static int insertionIndexForKey(@NonNull SparseBooleanArray sba, int key) {
    int low = 0;
    int high = sba.size();
    while (high - low > 0) {
        int middle = (low + high) >> 1;
        if (sba.keyAt(middle) < key)
            low = middle + 1;
        else
            high = middle;
    }
    return low;
}
 

private static int insertionIndexForKey(SparseBooleanArray sba, int key) {
    int low = 0;
    int high = sba.size();
    while (high - low > 0) {
        int middle = (low + high) >> 1;
        if (sba.keyAt(middle) < key)
            low = middle + 1;
        else
            high = middle;
    }
    return low;
}
 

/**
 * Show a message giving the selected item captions
 */
private void showSelectedItems() {
	final StringBuffer sb = new StringBuffer("Selection: ");

	// Get an array that tells us for each position whether the item is
	// checked or not
	// --
	final SparseBooleanArray checkedItems = listView.getCheckedItemPositions();
	if (checkedItems == null) {
		Toast.makeText(this, "No selection info available", Toast.LENGTH_LONG).show();
		return;
	}

	// For each element in the status array
	// --
	boolean isFirstSelected = true;
	final int checkedItemsCount = checkedItems.size();
	for (int i = 0; i < checkedItemsCount; ++i) {
		// This tells us the item position we are looking at
		// --
		final int position = checkedItems.keyAt(i);

		// This tells us the item status at the above position
		// --
		final boolean isChecked = checkedItems.valueAt(i);

		if (isChecked) {
			if (!isFirstSelected) {
				sb.append(", ");
			}
			sb.append(data.get(position).getCaption());
			isFirstSelected = false;
		}
	}

	// Show a message with the countries that are selected
	// --
	Toast.makeText(this, sb.toString(), Toast.LENGTH_LONG).show();
}
 

private static int findFirstSetIndex(@NonNull SparseBooleanArray sba, int rangeStart, int rangeEnd) {
    int size = sba.size();
    int i = insertionIndexForKey(sba, rangeStart);
    while (i < size && sba.keyAt(i) < rangeEnd && !sba.valueAt(i))
        i++;
    if (i == size || sba.keyAt(i) >= rangeEnd)
        return -1;
    return i;
}
 

private void hidePopUpMenu(ViewHolder holder) {
    SparseBooleanArray checkedItems = mListView.getCheckedItemPositions();
    if (checkedItems.size() > 0) {
        for (int i = 0; i < checkedItems.size(); i++) {
            int key = checkedItems.keyAt(i);
            if (checkedItems.get(key)) {
                holder.popup.setVisibility(View.INVISIBLE);
            }
        }
    } else {
        holder.popup.setVisibility(View.VISIBLE);
    }
}
 

private static int insertionIndexForKey(SparseBooleanArray sba, int key) {
    int low = 0;
    int high = sba.size();
    while (high - low > 0) {
        int middle = (low + high) >> 1;
        if (sba.keyAt(middle) < key)
            low = middle + 1;
        else
            high = middle;
    }
    return low;
}
 

private void hidePopUpMenu(ViewHolder holder) {
    SparseBooleanArray checkedItems = mListView.getCheckedItemPositions();
    if (checkedItems.size() > 0) {
        for (int i = 0; i < checkedItems.size(); i++) {
            int key = checkedItems.keyAt(i);
            if (checkedItems.get(key)) {
                holder.popup.setVisibility(View.INVISIBLE);
                }
        }
    } else {
        holder.popup.setVisibility(View.VISIBLE);
    }
}
 

private void hidePopUpMenu(ViewHolder holder) {
    SparseBooleanArray checkedItems = mListView.getCheckedItemPositions();
    if (checkedItems.size() > 0) {
        for (int i = 0; i < checkedItems.size(); i++) {
            int key = checkedItems.keyAt(i);
            if (checkedItems.get(key)) {
                holder.popup.setVisibility(View.INVISIBLE);
                }
        }
    } else {
        holder.popup.setVisibility(View.VISIBLE);
    }
}
 

private long[] getChecked(SparseBooleanArray array) {
  ArrayList<Long> checked = new ArrayList<Long>();
  for (int i = 0; i < array.size(); i++) {
    int key = array.keyAt(i);
    if (array.get(key)) {
      checked.add(trackIds[key]);
    }
  }
  long[] result = new long[checked.size()];
  for (int i = 0; i < checked.size(); i++) {
    result[i] = checked.get(i).longValue();
  }
  return result;
}
 

@Override
void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (isMultiChoiceList()) {
        ListAdapter adapter = choicesList.getAdapter();
        boolean[] checkedStates = new boolean[adapter.getCount()];
        SparseBooleanArray checkedPositions = choicesList.getCheckedItemPositions();
        for (int i = 0; i < checkedPositions.size(); i++) {
            if (checkedPositions.valueAt(i)) {
                checkedStates[checkedPositions.keyAt(i)] = true;
            }
        }
        outState.putBooleanArray(KEY_ITEM_CHECKED_STATES, checkedStates);
    }
}
 

private static int findFirstSetIndex(SparseBooleanArray sba, int rangeStart, int rangeEnd) {
    int size = sba.size();
    int i = insertionIndexForKey(sba, rangeStart);
    while (i < size && sba.keyAt(i) < rangeEnd && !sba.valueAt(i))
        i++;
    if (i == size || sba.keyAt(i) >= rangeEnd)
        return -1;
    return i;
}
 

private static int findFirstSetIndex(SparseBooleanArray sba, int rangeStart, int rangeEnd) {
    int size = sba.size();
    int i = insertionIndexForKey(sba, rangeStart);
    while (i < size && sba.keyAt(i) < rangeEnd && !sba.valueAt(i))
        i++;
    if (i == size || sba.keyAt(i) >= rangeEnd)
        return -1;
    return i;
}