下面列出了android.widget.ListAdapter#getItemViewType ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
int findCurrentSectionPosition(int fromPosition) {
ListAdapter adapter = getAdapter();
if (adapter instanceof SectionIndexer) {
// try fast way by asking section indexer
SectionIndexer indexer = (SectionIndexer) adapter;
int sectionPosition = indexer.getSectionForPosition(fromPosition);
int itemPosition = indexer.getPositionForSection(sectionPosition);
int typeView = adapter.getItemViewType(itemPosition);
if (isItemViewTypePinned(adapter, typeView)) {
return itemPosition;
} // else, no luck
}
// try slow way by looking through to the next section item above
for (int position=fromPosition; position>=0; position--) {
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) return position;
}
return -1; // no candidate found
}
int findFirstVisibleSectionPosition(int firstVisibleItem, int visibleItemCount) {
ListAdapter adapter = getAdapter();
int adapterDataCount = adapter.getCount();
if (getLastVisiblePosition() >= adapterDataCount)
return -1; // dataset has changed, no candidate
if (firstVisibleItem + visibleItemCount >= adapterDataCount) {//added to prevent index Outofbound (in case)
visibleItemCount = adapterDataCount - firstVisibleItem;
}
for (int childIndex = 0; childIndex < visibleItemCount; childIndex++) {
int position = firstVisibleItem + childIndex;
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) return position;
}
return -1;
}
int findCurrentSectionPosition(int fromPosition) {
ListAdapter adapter = getAdapter();
if (adapter instanceof SectionIndexer) {
// try fast way by asking section indexer
SectionIndexer indexer = (SectionIndexer) adapter;
int sectionPosition = indexer.getSectionForPosition(fromPosition);
int itemPosition = indexer.getPositionForSection(sectionPosition);
int typeView = adapter.getItemViewType(itemPosition);
if (isItemViewTypePinned(adapter, typeView)) {
return itemPosition;
} // else, no luck
}
// try slow way by looking through to the next section item above
for (int position=fromPosition; position>=0; position--) {
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) return position;
}
return -1; // no candidate found
}
int findCurrentSectionPosition(int fromPosition) {
ListAdapter adapter = getAdapter();
if (adapter instanceof SectionIndexer) {
// try fast way by asking section indexer
SectionIndexer indexer = (SectionIndexer) adapter;
int sectionPosition = indexer.getSectionForPosition(fromPosition);
int itemPosition = indexer.getPositionForSection(sectionPosition);
int typeView = adapter.getItemViewType(itemPosition);
if (isItemViewTypePinned(adapter, typeView)) {
return itemPosition;
} // else, no luck
}
// try slow way by looking through to the next section item above
for (int position = fromPosition; position >= 0; position--) {
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) return position;
}
return -1; // no candidate found
}
int findCurrentSectionPosition(int fromPosition) {
ListAdapter adapter = getAdapter();
if (adapter instanceof SectionIndexer) {
// try fast way by asking section indexer
SectionIndexer indexer = (SectionIndexer) adapter;
int sectionPosition = indexer.getSectionForPosition(fromPosition);
int itemPosition = indexer.getPositionForSection(sectionPosition);
int typeView = adapter.getItemViewType(itemPosition);
if (isItemViewTypePinned(adapter, typeView)) {
return itemPosition;
} // else, no luck
}
// try slow way by looking through to the next section item above
for (int position=fromPosition; position>=0; position--) {
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) return position;
}
return -1; // no candidate found
}
/**
* Get the type of {@link View} that will be created by {@link #getView(int, View, ViewGroup)} for the specified
* item.
* @param position Position of the item whose data we want
*/
@Override
public int getItemViewType(int position) {
int typeOffset = 0;
int result = -1;
for (ListAdapter piece : pieces) {
int size = piece.getCount();
if (position < size) {
result = typeOffset + piece.getItemViewType(position);
break;
}
position -= size;
typeOffset += piece.getViewTypeCount();
}
return (result);
}
int findFirstVisibleSectionPosition(int firstVisibleItem, int visibleItemCount) {
ListAdapter adapter = getAdapter();
int adapterDataCount = adapter.getCount();
// dataset has changed, no candidate
if (getLastVisiblePosition() >= adapterDataCount) {
return -1;
}
//added to prevent index Outofbound (in case)
if (firstVisibleItem + visibleItemCount >= adapterDataCount) {
visibleItemCount = adapterDataCount - firstVisibleItem;
}
for (int childIndex = 0; childIndex < visibleItemCount; childIndex++) {
int position = firstVisibleItem + childIndex;
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) {
return position;
}
}
return -1;
}
int findFirstVisibleSectionPosition(int firstVisibleItem, int visibleItemCount) {
ListAdapter adapter = getAdapter();
for (int childIndex = 0; childIndex < visibleItemCount; childIndex++) {
int position = firstVisibleItem + childIndex;
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) return position;
}
return -1;
}
int findFirstVisibleSectionPosition(int firstVisibleItem, int visibleItemCount) {
ListAdapter adapter = getAdapter();
for (int childIndex = 0; childIndex < visibleItemCount; childIndex++) {
int position = firstVisibleItem + childIndex;
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) return position;
}
return -1;
}
public int getItemViewType(int position) {
final ListAdapter adapter = mListAdapter;
if (adapter != null)
return adapter.getItemViewType(position);
else
return 0;
}
int findCurrentSectionPosition(int fromPosition) {
ListAdapter adapter = getAdapter();
// dataset has changed, no candidate
if (fromPosition >= adapter.getCount()) {
return -1;
}
if (adapter instanceof SectionIndexer) {
// try fast way by asking section indexer
SectionIndexer indexer = (SectionIndexer) adapter;
int sectionPosition = indexer.getSectionForPosition(fromPosition);
int itemPosition = indexer.getPositionForSection(sectionPosition);
int typeView = adapter.getItemViewType(itemPosition);
if (isItemViewTypePinned(adapter, typeView)) {
return itemPosition;
} // else, no luck
}
// try slow way by looking through to the next section item above
for (int position = fromPosition; position >= 0; position--) {
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) {
return position;
}
}
// no candidate found
return -1;
}
int findCurrentSectionPosition(int fromPosition) {
ListAdapter adapter = getAdapter();
// dataset has changed, no candidate
if (fromPosition >= adapter.getCount()) {
return -1;
}
if (adapter instanceof SectionIndexer) {
// try fast way by asking section indexer
SectionIndexer indexer = (SectionIndexer) adapter;
int sectionPosition = indexer.getSectionForPosition(fromPosition);
int itemPosition = indexer.getPositionForSection(sectionPosition);
int typeView = adapter.getItemViewType(itemPosition);
if (isItemViewTypePinned(adapter, typeView)) {
return itemPosition;
} // else, no luck
}
// try slow way by looking through to the next section item above
for (int position = fromPosition; position >= 0; position--) {
int viewType = adapter.getItemViewType(position);
if (isItemViewTypePinned(adapter, viewType)) {
return position;
}
}
// no candidate found
return -1;
}
private int getChildHeight(int position) {
if (position == mSrcPos) {
return 0;
}
View v = getChildAt(position - getFirstVisiblePosition());
if (v != null) {
// item is onscreen, therefore child height is valid,
// hence the "true"
return getChildHeight(position, v, false);
} else {
// item is offscreen
// first check cache for child height at this position
int childHeight = mChildHeightCache.get(position);
if (childHeight != -1) {
// Log.d("mobeta", "found child height in cache!");
return childHeight;
}
final ListAdapter adapter = getAdapter();
int type = adapter.getItemViewType(position);
// There might be a better place for checking for the following
final int typeCount = adapter.getViewTypeCount();
if (typeCount != mSampleViewTypes.length) {
mSampleViewTypes = new View[typeCount];
}
if (type >= 0) {
if (mSampleViewTypes[type] == null) {
v = adapter.getView(position, null, this);
mSampleViewTypes[type] = v;
} else {
v = adapter.getView(position, mSampleViewTypes[type], this);
}
} else {
// type is HEADER_OR_FOOTER or IGNORE
v = adapter.getView(position, null, this);
}
// current child height is invalid, hence "true" below
childHeight = getChildHeight(position, v, true);
// cache it because this could have been expensive
mChildHeightCache.add(position, childHeight);
return childHeight;
}
}
private int getChildHeight(int position) {
if (position == mSrcPos) {
return 0;
}
View v = getChildAt(position - getFirstVisiblePosition());
if (v != null) {
// item is onscreen, therefore child height is valid,
// hence the "true"
return getChildHeight(position, v, false);
} else {
// item is offscreen
// first check cache for child height at this position
int childHeight = mChildHeightCache.get(position);
if (childHeight != -1) {
// Log.d("mobeta", "found child height in cache!");
return childHeight;
}
final ListAdapter adapter = getAdapter();
int type = adapter.getItemViewType(position);
// There might be a better place for checking for the following
final int typeCount = adapter.getViewTypeCount();
if (typeCount != mSampleViewTypes.length) {
mSampleViewTypes = new View[typeCount];
}
if (type >= 0) {
if (mSampleViewTypes[type] == null) {
v = adapter.getView(position, null, this);
mSampleViewTypes[type] = v;
} else {
v = adapter.getView(position, mSampleViewTypes[type], this);
}
} else {
// type is HEADER_OR_FOOTER or IGNORE
v = adapter.getView(position, null, this);
}
// current child height is invalid, hence "true" below
childHeight = getChildHeight(position, v, true);
// cache it because this could have been expensive
mChildHeightCache.add(position, childHeight);
return childHeight;
}
}
private int getChildHeight(int position) {
if (position == mSrcPos) {
return 0;
}
View v = getChildAt(position - getFirstVisiblePosition());
if (v != null) {
// item is onscreen, therefore child height is valid,
// hence the "true"
return getChildHeight(position, v, false);
} else {
// item is offscreen
// first check cache for child height at this position
int childHeight = mChildHeightCache.get(position);
if (childHeight != -1) {
return childHeight;
}
final ListAdapter adapter = getAdapter();
int type = adapter.getItemViewType(position);
// There might be a better place for checking for the following
final int typeCount = adapter.getViewTypeCount();
if (typeCount != mSampleViewTypes.length) {
mSampleViewTypes = new View[typeCount];
}
if (type >= 0) {
if (mSampleViewTypes[type] == null) {
v = adapter.getView(position, null, this);
mSampleViewTypes[type] = v;
} else {
v = adapter.getView(position, mSampleViewTypes[type], this);
}
} else {
// type is HEADER_OR_FOOTER or IGNORE
v = adapter.getView(position, null, this);
}
// current child height is invalid, hence "true" below
childHeight = getChildHeight(position, v, true);
// cache it because this could have been expensive
mChildHeightCache.add(position, childHeight);
return childHeight;
}
}
private int getChildHeight(int position) {
if (position == mSrcPos) {
return 0;
}
View v = getChildAt(position - getFirstVisiblePosition());
if (v != null) {
// item is onscreen, therefore child height is valid,
// hence the "true"
return getChildHeight(position, v, false);
} else {
// item is offscreen
// first check cache for child height at this position
int childHeight = mChildHeightCache.get(position);
if (childHeight != -1) {
// Log.d("mobeta", "found child height in cache!");
return childHeight;
}
final ListAdapter adapter = getAdapter();
int type = adapter.getItemViewType(position);
// There might be a better place for checking for the following
final int typeCount = adapter.getViewTypeCount();
if (typeCount != mSampleViewTypes.length) {
mSampleViewTypes = new View[typeCount];
}
if (type >= 0) {
if (mSampleViewTypes[type] == null) {
v = adapter.getView(position, null, this);
mSampleViewTypes[type] = v;
} else {
v = adapter.getView(position, mSampleViewTypes[type], this);
}
} else {
// type is HEADER_OR_FOOTER or IGNORE
v = adapter.getView(position, null, this);
}
// current child height is invalid, hence "true" below
childHeight = getChildHeight(position, v, true);
// cache it because this could have been expensive
mChildHeightCache.add(position, childHeight);
return childHeight;
}
}
private int getChildHeight(int position) {
if (position == mSrcPos) {
return 0;
}
View v = getChildAt(position - getFirstVisiblePosition());
if (v != null) {
// item is onscreen, therefore child height is valid,
// hence the "true"
return getChildHeight(position, v, false);
} else {
// item is offscreen
// first check cache for child height at this position
int childHeight = mChildHeightCache.get(position);
if (childHeight != -1) {
// Log.d("mobeta", "found child height in cache!");
return childHeight;
}
final ListAdapter adapter = getAdapter();
int type = adapter.getItemViewType(position);
// There might be a better place for checking for the following
final int typeCount = adapter.getViewTypeCount();
if (typeCount != mSampleViewTypes.length) {
mSampleViewTypes = new View[typeCount];
}
if (type >= 0) {
if (mSampleViewTypes[type] == null) {
v = adapter.getView(position, null, this);
mSampleViewTypes[type] = v;
} else {
v = adapter.getView(position, mSampleViewTypes[type], this);
}
} else {
// type is HEADER_OR_FOOTER or IGNORE
v = adapter.getView(position, null, this);
}
// current child height is invalid, hence "true" below
childHeight = getChildHeight(position, v, true);
// cache it because this could have been expensive
mChildHeightCache.add(position, childHeight);
return childHeight;
}
}
private int getChildHeight(int position) {
if (position == mSrcPos) {
return 0;
}
View v = getChildAt(position - getFirstVisiblePosition());
if (v != null) {
// item is onscreen, therefore child height is valid,
// hence the "true"
return getChildHeight(position, v, false);
} else {
// item is offscreen
// first check cache for child height at this position
int childHeight = mChildHeightCache.get(position);
if (childHeight != -1) {
// Log.d("mobeta", "found child height in cache!");
return childHeight;
}
final ListAdapter adapter = getAdapter();
int type = adapter.getItemViewType(position);
// There might be a better place for checking for the following
final int typeCount = adapter.getViewTypeCount();
if (typeCount != mSampleViewTypes.length) {
mSampleViewTypes = new View[typeCount];
}
if (type >= 0) {
if (mSampleViewTypes[type] == null) {
v = adapter.getView(position, null, this);
mSampleViewTypes[type] = v;
} else {
v = adapter.getView(position, mSampleViewTypes[type], this);
}
} else {
// type is HEADER_OR_FOOTER or IGNORE
v = adapter.getView(position, null, this);
}
// current child height is invalid, hence "true" below
childHeight = getChildHeight(position, v, true);
// cache it because this could have been expensive
mChildHeightCache.add(position, childHeight);
return childHeight;
}
}
private int getChildHeight(int position) {
if (position == mSrcPos) {
return 0;
}
View v = getChildAt(position - getFirstVisiblePosition());
if (v != null) {
// item is onscreen, therefore child height is valid,
// hence the "true"
return getChildHeight(position, v, false);
} else {
// item is offscreen
// first check cache for child height at this position
int childHeight = mChildHeightCache.get(position);
if (childHeight != -1) {
// Log.d("mobeta", "found child height in cache!");
return childHeight;
}
final ListAdapter adapter = getAdapter();
int type = adapter.getItemViewType(position);
// There might be a better place for checking for the following
final int typeCount = adapter.getViewTypeCount();
if (typeCount != mSampleViewTypes.length) {
mSampleViewTypes = new View[typeCount];
}
if (type >= 0) {
if (mSampleViewTypes[type] == null) {
v = adapter.getView(position, null, this);
mSampleViewTypes[type] = v;
} else {
v = adapter.getView(position, mSampleViewTypes[type], this);
}
} else {
// type is HEADER_OR_FOOTER or IGNORE
v = adapter.getView(position, null, this);
}
// current child height is invalid, hence "true" below
childHeight = getChildHeight(position, v, true);
// cache it because this could have been expensive
mChildHeightCache.add(position, childHeight);
return childHeight;
}
}
/**
* Measures the height of the given range of children (inclusive) and returns the height
* with this ListView's padding and divider heights included. If maxHeight is provided, the
* measuring will stop when the current height reaches maxHeight.
*
* @param widthMeasureSpec The width measure spec to be given to a child's
* {@link View#measure(int, int)}.
* @param startPosition The position of the first child to be shown.
* @param endPosition The (inclusive) position of the last child to be
* shown. Specify {@link #NO_POSITION} if the last child
* should be the last available child from the adapter.
* @param maxHeight The maximum height that will be returned (if all the
* children don't fit in this value, this value will be
* returned).
* @param disallowPartialChildPosition In general, whether the returned height should only
* contain entire children. This is more powerful--it is
* the first inclusive position at which partial
* children will not be allowed. Example: it looks nice
* to have at least 3 completely visible children, and
* in portrait this will most likely fit; but in
* landscape there could be times when even 2 children
* can not be completely shown, so a value of 2
* (remember, inclusive) would be good (assuming
* startPosition is 0).
* @return The height of this ListView with the given children.
*/
public int measureHeightOfChildrenCompat(int widthMeasureSpec, int startPosition,
int endPosition, final int maxHeight,
int disallowPartialChildPosition) {
final int paddingTop = getListPaddingTop();
final int paddingBottom = getListPaddingBottom();
final int paddingLeft = getListPaddingLeft();
final int paddingRight = getListPaddingRight();
final int reportedDividerHeight = getDividerHeight();
final Drawable divider = getDivider();
final ListAdapter adapter = getAdapter();
if (adapter == null) {
return paddingTop + paddingBottom;
}
// Include the padding of the list
int returnedHeight = paddingTop + paddingBottom;
final int dividerHeight = ((reportedDividerHeight > 0) && divider != null)
? reportedDividerHeight : 0;
// The previous height value that was less than maxHeight and contained
// no partial children
int prevHeightWithoutPartialChild = 0;
View child = null;
int viewType = 0;
int count = adapter.getCount();
for (int i = 0; i < count; i++) {
int newType = adapter.getItemViewType(i);
if (newType != viewType) {
child = null;
viewType = newType;
}
child = adapter.getView(i, child, this);
// Compute child height spec
int heightMeasureSpec;
ViewGroup.LayoutParams childLp = child.getLayoutParams();
if (childLp == null) {
childLp = generateDefaultLayoutParams();
child.setLayoutParams(childLp);
}
if (childLp.height > 0) {
heightMeasureSpec = MeasureSpec.makeMeasureSpec(childLp.height,
MeasureSpec.EXACTLY);
} else {
heightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(widthMeasureSpec, heightMeasureSpec);
// Since this view was measured directly aginst the parent measure
// spec, we must measure it again before reuse.
child.forceLayout();
if (i > 0) {
// Count the divider for all but one child
returnedHeight += dividerHeight;
}
returnedHeight += child.getMeasuredHeight();
if (returnedHeight >= maxHeight) {
// We went over, figure out which height to return. If returnedHeight >
// maxHeight, then the i'th position did not fit completely.
return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1)
&& (i > disallowPartialChildPosition) // We've past the min pos
&& (prevHeightWithoutPartialChild > 0) // We have a prev height
&& (returnedHeight != maxHeight) // i'th child did not fit completely
? prevHeightWithoutPartialChild
: maxHeight;
}
if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) {
prevHeightWithoutPartialChild = returnedHeight;
}
}
// At this point, we went through the range of children, and they each
// completely fit, so return the returnedHeight
return returnedHeight;
}