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Diffstat (limited to 'actionbarsherlock/src/com/actionbarsherlock/internal/widget/IcsAdapterView.java')
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diff --git a/actionbarsherlock/src/com/actionbarsherlock/internal/widget/IcsAdapterView.java b/actionbarsherlock/src/com/actionbarsherlock/internal/widget/IcsAdapterView.java new file mode 100644 index 000000000..c786dc5c1 --- /dev/null +++ b/actionbarsherlock/src/com/actionbarsherlock/internal/widget/IcsAdapterView.java @@ -0,0 +1,1160 @@ +/* + * Copyright (C) 2006 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package com.actionbarsherlock.internal.widget; + +import android.content.Context; +import android.database.DataSetObserver; +import android.os.Parcelable; +import android.os.SystemClock; +import android.util.AttributeSet; +import android.util.SparseArray; +import android.view.ContextMenu; +import android.view.SoundEffectConstants; +import android.view.View; +import android.view.ViewDebug; +import android.view.ViewGroup; +import android.view.accessibility.AccessibilityEvent; +import android.view.accessibility.AccessibilityNodeInfo; +import android.widget.Adapter; +import android.widget.AdapterView.OnItemClickListener; +import android.widget.ListView; + + +/** + * An AdapterView is a view whose children are determined by an {@link Adapter}. + * + * <p> + * See {@link ListView}, {@link GridView}, {@link Spinner} and + * {@link Gallery} for commonly used subclasses of AdapterView. + * + * <div class="special reference"> + * <h3>Developer Guides</h3> + * <p>For more information about using AdapterView, read the + * <a href="{@docRoot}guide/topics/ui/binding.html">Binding to Data with AdapterView</a> + * developer guide.</p></div> + */ +public abstract class IcsAdapterView<T extends Adapter> extends ViewGroup { + + /** + * The item view type returned by {@link Adapter#getItemViewType(int)} when + * the adapter does not want the item's view recycled. + */ + public static final int ITEM_VIEW_TYPE_IGNORE = -1; + + /** + * The item view type returned by {@link Adapter#getItemViewType(int)} when + * the item is a header or footer. + */ + public static final int ITEM_VIEW_TYPE_HEADER_OR_FOOTER = -2; + + /** + * The position of the first child displayed + */ + @ViewDebug.ExportedProperty(category = "scrolling") + int mFirstPosition = 0; + + /** + * The offset in pixels from the top of the AdapterView to the top + * of the view to select during the next layout. + */ + int mSpecificTop; + + /** + * Position from which to start looking for mSyncRowId + */ + int mSyncPosition; + + /** + * Row id to look for when data has changed + */ + long mSyncRowId = INVALID_ROW_ID; + + /** + * Height of the view when mSyncPosition and mSyncRowId where set + */ + long mSyncHeight; + + /** + * True if we need to sync to mSyncRowId + */ + boolean mNeedSync = false; + + /** + * Indicates whether to sync based on the selection or position. Possible + * values are {@link #SYNC_SELECTED_POSITION} or + * {@link #SYNC_FIRST_POSITION}. + */ + int mSyncMode; + + /** + * Our height after the last layout + */ + private int mLayoutHeight; + + /** + * Sync based on the selected child + */ + static final int SYNC_SELECTED_POSITION = 0; + + /** + * Sync based on the first child displayed + */ + static final int SYNC_FIRST_POSITION = 1; + + /** + * Maximum amount of time to spend in {@link #findSyncPosition()} + */ + static final int SYNC_MAX_DURATION_MILLIS = 100; + + /** + * Indicates that this view is currently being laid out. + */ + boolean mInLayout = false; + + /** + * The listener that receives notifications when an item is selected. + */ + OnItemSelectedListener mOnItemSelectedListener; + + /** + * The listener that receives notifications when an item is clicked. + */ + OnItemClickListener mOnItemClickListener; + + /** + * The listener that receives notifications when an item is long clicked. + */ + OnItemLongClickListener mOnItemLongClickListener; + + /** + * True if the data has changed since the last layout + */ + boolean mDataChanged; + + /** + * The position within the adapter's data set of the item to select + * during the next layout. + */ + @ViewDebug.ExportedProperty(category = "list") + int mNextSelectedPosition = INVALID_POSITION; + + /** + * The item id of the item to select during the next layout. + */ + long mNextSelectedRowId = INVALID_ROW_ID; + + /** + * The position within the adapter's data set of the currently selected item. + */ + @ViewDebug.ExportedProperty(category = "list") + int mSelectedPosition = INVALID_POSITION; + + /** + * The item id of the currently selected item. + */ + long mSelectedRowId = INVALID_ROW_ID; + + /** + * View to show if there are no items to show. + */ + private View mEmptyView; + + /** + * The number of items in the current adapter. + */ + @ViewDebug.ExportedProperty(category = "list") + int mItemCount; + + /** + * The number of items in the adapter before a data changed event occurred. + */ + int mOldItemCount; + + /** + * Represents an invalid position. All valid positions are in the range 0 to 1 less than the + * number of items in the current adapter. + */ + public static final int INVALID_POSITION = -1; + + /** + * Represents an empty or invalid row id + */ + public static final long INVALID_ROW_ID = Long.MIN_VALUE; + + /** + * The last selected position we used when notifying + */ + int mOldSelectedPosition = INVALID_POSITION; + + /** + * The id of the last selected position we used when notifying + */ + long mOldSelectedRowId = INVALID_ROW_ID; + + /** + * Indicates what focusable state is requested when calling setFocusable(). + * In addition to this, this view has other criteria for actually + * determining the focusable state (such as whether its empty or the text + * filter is shown). + * + * @see #setFocusable(boolean) + * @see #checkFocus() + */ + private boolean mDesiredFocusableState; + private boolean mDesiredFocusableInTouchModeState; + + private SelectionNotifier mSelectionNotifier; + /** + * When set to true, calls to requestLayout() will not propagate up the parent hierarchy. + * This is used to layout the children during a layout pass. + */ + boolean mBlockLayoutRequests = false; + + public IcsAdapterView(Context context) { + super(context); + } + + public IcsAdapterView(Context context, AttributeSet attrs) { + super(context, attrs); + } + + public IcsAdapterView(Context context, AttributeSet attrs, int defStyle) { + super(context, attrs, defStyle); + } + + /** + * Register a callback to be invoked when an item in this AdapterView has + * been clicked. + * + * @param listener The callback that will be invoked. + */ + public void setOnItemClickListener(OnItemClickListener listener) { + mOnItemClickListener = listener; + } + + /** + * @return The callback to be invoked with an item in this AdapterView has + * been clicked, or null id no callback has been set. + */ + public final OnItemClickListener getOnItemClickListener() { + return mOnItemClickListener; + } + + /** + * Call the OnItemClickListener, if it is defined. + * + * @param view The view within the AdapterView that was clicked. + * @param position The position of the view in the adapter. + * @param id The row id of the item that was clicked. + * @return True if there was an assigned OnItemClickListener that was + * called, false otherwise is returned. + */ + public boolean performItemClick(View view, int position, long id) { + if (mOnItemClickListener != null) { + playSoundEffect(SoundEffectConstants.CLICK); + if (view != null) { + view.sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED); + } + mOnItemClickListener.onItemClick(/*this*/null, view, position, id); + return true; + } + + return false; + } + + /** + * Interface definition for a callback to be invoked when an item in this + * view has been clicked and held. + */ + public interface OnItemLongClickListener { + /** + * Callback method to be invoked when an item in this view has been + * clicked and held. + * + * Implementers can call getItemAtPosition(position) if they need to access + * the data associated with the selected item. + * + * @param parent The AbsListView where the click happened + * @param view The view within the AbsListView that was clicked + * @param position The position of the view in the list + * @param id The row id of the item that was clicked + * + * @return true if the callback consumed the long click, false otherwise + */ + boolean onItemLongClick(IcsAdapterView<?> parent, View view, int position, long id); + } + + + /** + * Register a callback to be invoked when an item in this AdapterView has + * been clicked and held + * + * @param listener The callback that will run + */ + public void setOnItemLongClickListener(OnItemLongClickListener listener) { + if (!isLongClickable()) { + setLongClickable(true); + } + mOnItemLongClickListener = listener; + } + + /** + * @return The callback to be invoked with an item in this AdapterView has + * been clicked and held, or null id no callback as been set. + */ + public final OnItemLongClickListener getOnItemLongClickListener() { + return mOnItemLongClickListener; + } + + /** + * Interface definition for a callback to be invoked when + * an item in this view has been selected. + */ + public interface OnItemSelectedListener { + /** + * <p>Callback method to be invoked when an item in this view has been + * selected. This callback is invoked only when the newly selected + * position is different from the previously selected position or if + * there was no selected item.</p> + * + * Impelmenters can call getItemAtPosition(position) if they need to access the + * data associated with the selected item. + * + * @param parent The AdapterView where the selection happened + * @param view The view within the AdapterView that was clicked + * @param position The position of the view in the adapter + * @param id The row id of the item that is selected + */ + void onItemSelected(IcsAdapterView<?> parent, View view, int position, long id); + + /** + * Callback method to be invoked when the selection disappears from this + * view. The selection can disappear for instance when touch is activated + * or when the adapter becomes empty. + * + * @param parent The AdapterView that now contains no selected item. + */ + void onNothingSelected(IcsAdapterView<?> parent); + } + + + /** + * Register a callback to be invoked when an item in this AdapterView has + * been selected. + * + * @param listener The callback that will run + */ + public void setOnItemSelectedListener(OnItemSelectedListener listener) { + mOnItemSelectedListener = listener; + } + + public final OnItemSelectedListener getOnItemSelectedListener() { + return mOnItemSelectedListener; + } + + /** + * Extra menu information provided to the + * {@link android.view.View.OnCreateContextMenuListener#onCreateContextMenu(ContextMenu, View, ContextMenuInfo) } + * callback when a context menu is brought up for this AdapterView. + * + */ + public static class AdapterContextMenuInfo implements ContextMenu.ContextMenuInfo { + + public AdapterContextMenuInfo(View targetView, int position, long id) { + this.targetView = targetView; + this.position = position; + this.id = id; + } + + /** + * The child view for which the context menu is being displayed. This + * will be one of the children of this AdapterView. + */ + public View targetView; + + /** + * The position in the adapter for which the context menu is being + * displayed. + */ + public int position; + + /** + * The row id of the item for which the context menu is being displayed. + */ + public long id; + } + + /** + * Returns the adapter currently associated with this widget. + * + * @return The adapter used to provide this view's content. + */ + public abstract T getAdapter(); + + /** + * Sets the adapter that provides the data and the views to represent the data + * in this widget. + * + * @param adapter The adapter to use to create this view's content. + */ + public abstract void setAdapter(T adapter); + + /** + * This method is not supported and throws an UnsupportedOperationException when called. + * + * @param child Ignored. + * + * @throws UnsupportedOperationException Every time this method is invoked. + */ + @Override + public void addView(View child) { + throw new UnsupportedOperationException("addView(View) is not supported in AdapterView"); + } + + /** + * This method is not supported and throws an UnsupportedOperationException when called. + * + * @param child Ignored. + * @param index Ignored. + * + * @throws UnsupportedOperationException Every time this method is invoked. + */ + @Override + public void addView(View child, int index) { + throw new UnsupportedOperationException("addView(View, int) is not supported in AdapterView"); + } + + /** + * This method is not supported and throws an UnsupportedOperationException when called. + * + * @param child Ignored. + * @param params Ignored. + * + * @throws UnsupportedOperationException Every time this method is invoked. + */ + @Override + public void addView(View child, LayoutParams params) { + throw new UnsupportedOperationException("addView(View, LayoutParams) " + + "is not supported in AdapterView"); + } + + /** + * This method is not supported and throws an UnsupportedOperationException when called. + * + * @param child Ignored. + * @param index Ignored. + * @param params Ignored. + * + * @throws UnsupportedOperationException Every time this method is invoked. + */ + @Override + public void addView(View child, int index, LayoutParams params) { + throw new UnsupportedOperationException("addView(View, int, LayoutParams) " + + "is not supported in AdapterView"); + } + + /** + * This method is not supported and throws an UnsupportedOperationException when called. + * + * @param child Ignored. + * + * @throws UnsupportedOperationException Every time this method is invoked. + */ + @Override + public void removeView(View child) { + throw new UnsupportedOperationException("removeView(View) is not supported in AdapterView"); + } + + /** + * This method is not supported and throws an UnsupportedOperationException when called. + * + * @param index Ignored. + * + * @throws UnsupportedOperationException Every time this method is invoked. + */ + @Override + public void removeViewAt(int index) { + throw new UnsupportedOperationException("removeViewAt(int) is not supported in AdapterView"); + } + + /** + * This method is not supported and throws an UnsupportedOperationException when called. + * + * @throws UnsupportedOperationException Every time this method is invoked. + */ + @Override + public void removeAllViews() { + throw new UnsupportedOperationException("removeAllViews() is not supported in AdapterView"); + } + + @Override + protected void onLayout(boolean changed, int left, int top, int right, int bottom) { + mLayoutHeight = getHeight(); + } + + /** + * Return the position of the currently selected item within the adapter's data set + * + * @return int Position (starting at 0), or {@link #INVALID_POSITION} if there is nothing selected. + */ + @ViewDebug.CapturedViewProperty + public int getSelectedItemPosition() { + return mNextSelectedPosition; + } + + /** + * @return The id corresponding to the currently selected item, or {@link #INVALID_ROW_ID} + * if nothing is selected. + */ + @ViewDebug.CapturedViewProperty + public long getSelectedItemId() { + return mNextSelectedRowId; + } + + /** + * @return The view corresponding to the currently selected item, or null + * if nothing is selected + */ + public abstract View getSelectedView(); + + /** + * @return The data corresponding to the currently selected item, or + * null if there is nothing selected. + */ + public Object getSelectedItem() { + T adapter = getAdapter(); + int selection = getSelectedItemPosition(); + if (adapter != null && adapter.getCount() > 0 && selection >= 0) { + return adapter.getItem(selection); + } else { + return null; + } + } + + /** + * @return The number of items owned by the Adapter associated with this + * AdapterView. (This is the number of data items, which may be + * larger than the number of visible views.) + */ + @ViewDebug.CapturedViewProperty + public int getCount() { + return mItemCount; + } + + /** + * Get the position within the adapter's data set for the view, where view is a an adapter item + * or a descendant of an adapter item. + * + * @param view an adapter item, or a descendant of an adapter item. This must be visible in this + * AdapterView at the time of the call. + * @return the position within the adapter's data set of the view, or {@link #INVALID_POSITION} + * if the view does not correspond to a list item (or it is not currently visible). + */ + public int getPositionForView(View view) { + View listItem = view; + try { + View v; + while (!(v = (View) listItem.getParent()).equals(this)) { + listItem = v; + } + } catch (ClassCastException e) { + // We made it up to the window without find this list view + return INVALID_POSITION; + } + + // Search the children for the list item + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + if (getChildAt(i).equals(listItem)) { + return mFirstPosition + i; + } + } + + // Child not found! + return INVALID_POSITION; + } + + /** + * Returns the position within the adapter's data set for the first item + * displayed on screen. + * + * @return The position within the adapter's data set + */ + public int getFirstVisiblePosition() { + return mFirstPosition; + } + + /** + * Returns the position within the adapter's data set for the last item + * displayed on screen. + * + * @return The position within the adapter's data set + */ + public int getLastVisiblePosition() { + return mFirstPosition + getChildCount() - 1; + } + + /** + * Sets the currently selected item. To support accessibility subclasses that + * override this method must invoke the overriden super method first. + * + * @param position Index (starting at 0) of the data item to be selected. + */ + public abstract void setSelection(int position); + + /** + * Sets the view to show if the adapter is empty + */ + public void setEmptyView(View emptyView) { + mEmptyView = emptyView; + + final T adapter = getAdapter(); + final boolean empty = ((adapter == null) || adapter.isEmpty()); + updateEmptyStatus(empty); + } + + /** + * When the current adapter is empty, the AdapterView can display a special view + * call the empty view. The empty view is used to provide feedback to the user + * that no data is available in this AdapterView. + * + * @return The view to show if the adapter is empty. + */ + public View getEmptyView() { + return mEmptyView; + } + + /** + * Indicates whether this view is in filter mode. Filter mode can for instance + * be enabled by a user when typing on the keyboard. + * + * @return True if the view is in filter mode, false otherwise. + */ + boolean isInFilterMode() { + return false; + } + + @Override + public void setFocusable(boolean focusable) { + final T adapter = getAdapter(); + final boolean empty = adapter == null || adapter.getCount() == 0; + + mDesiredFocusableState = focusable; + if (!focusable) { + mDesiredFocusableInTouchModeState = false; + } + + super.setFocusable(focusable && (!empty || isInFilterMode())); + } + + @Override + public void setFocusableInTouchMode(boolean focusable) { + final T adapter = getAdapter(); + final boolean empty = adapter == null || adapter.getCount() == 0; + + mDesiredFocusableInTouchModeState = focusable; + if (focusable) { + mDesiredFocusableState = true; + } + + super.setFocusableInTouchMode(focusable && (!empty || isInFilterMode())); + } + + void checkFocus() { + final T adapter = getAdapter(); + final boolean empty = adapter == null || adapter.getCount() == 0; + final boolean focusable = !empty || isInFilterMode(); + // The order in which we set focusable in touch mode/focusable may matter + // for the client, see View.setFocusableInTouchMode() comments for more + // details + super.setFocusableInTouchMode(focusable && mDesiredFocusableInTouchModeState); + super.setFocusable(focusable && mDesiredFocusableState); + if (mEmptyView != null) { + updateEmptyStatus((adapter == null) || adapter.isEmpty()); + } + } + + /** + * Update the status of the list based on the empty parameter. If empty is true and + * we have an empty view, display it. In all the other cases, make sure that the listview + * is VISIBLE and that the empty view is GONE (if it's not null). + */ + private void updateEmptyStatus(boolean empty) { + if (isInFilterMode()) { + empty = false; + } + + if (empty) { + if (mEmptyView != null) { + mEmptyView.setVisibility(View.VISIBLE); + setVisibility(View.GONE); + } else { + // If the caller just removed our empty view, make sure the list view is visible + setVisibility(View.VISIBLE); + } + + // We are now GONE, so pending layouts will not be dispatched. + // Force one here to make sure that the state of the list matches + // the state of the adapter. + if (mDataChanged) { + this.onLayout(false, getLeft(), getTop(), getRight(), getBottom()); + } + } else { + if (mEmptyView != null) mEmptyView.setVisibility(View.GONE); + setVisibility(View.VISIBLE); + } + } + + /** + * Gets the data associated with the specified position in the list. + * + * @param position Which data to get + * @return The data associated with the specified position in the list + */ + public Object getItemAtPosition(int position) { + T adapter = getAdapter(); + return (adapter == null || position < 0) ? null : adapter.getItem(position); + } + + public long getItemIdAtPosition(int position) { + T adapter = getAdapter(); + return (adapter == null || position < 0) ? INVALID_ROW_ID : adapter.getItemId(position); + } + + @Override + public void setOnClickListener(OnClickListener l) { + throw new RuntimeException("Don't call setOnClickListener for an AdapterView. " + + "You probably want setOnItemClickListener instead"); + } + + /** + * Override to prevent freezing of any views created by the adapter. + */ + @Override + protected void dispatchSaveInstanceState(SparseArray<Parcelable> container) { + dispatchFreezeSelfOnly(container); + } + + /** + * Override to prevent thawing of any views created by the adapter. + */ + @Override + protected void dispatchRestoreInstanceState(SparseArray<Parcelable> container) { + dispatchThawSelfOnly(container); + } + + class AdapterDataSetObserver extends DataSetObserver { + + private Parcelable mInstanceState = null; + + @Override + public void onChanged() { + mDataChanged = true; + mOldItemCount = mItemCount; + mItemCount = getAdapter().getCount(); + + // Detect the case where a cursor that was previously invalidated has + // been repopulated with new data. + if (IcsAdapterView.this.getAdapter().hasStableIds() && mInstanceState != null + && mOldItemCount == 0 && mItemCount > 0) { + IcsAdapterView.this.onRestoreInstanceState(mInstanceState); + mInstanceState = null; + } else { + rememberSyncState(); + } + checkFocus(); + requestLayout(); + } + + @Override + public void onInvalidated() { + mDataChanged = true; + + if (IcsAdapterView.this.getAdapter().hasStableIds()) { + // Remember the current state for the case where our hosting activity is being + // stopped and later restarted + mInstanceState = IcsAdapterView.this.onSaveInstanceState(); + } + + // Data is invalid so we should reset our state + mOldItemCount = mItemCount; + mItemCount = 0; + mSelectedPosition = INVALID_POSITION; + mSelectedRowId = INVALID_ROW_ID; + mNextSelectedPosition = INVALID_POSITION; + mNextSelectedRowId = INVALID_ROW_ID; + mNeedSync = false; + + checkFocus(); + requestLayout(); + } + + public void clearSavedState() { + mInstanceState = null; + } + } + + @Override + protected void onDetachedFromWindow() { + super.onDetachedFromWindow(); + removeCallbacks(mSelectionNotifier); + } + + private class SelectionNotifier implements Runnable { + public void run() { + if (mDataChanged) { + // Data has changed between when this SelectionNotifier + // was posted and now. We need to wait until the AdapterView + // has been synched to the new data. + if (getAdapter() != null) { + post(this); + } + } else { + fireOnSelected(); + } + } + } + + void selectionChanged() { + if (mOnItemSelectedListener != null) { + if (mInLayout || mBlockLayoutRequests) { + // If we are in a layout traversal, defer notification + // by posting. This ensures that the view tree is + // in a consistent state and is able to accomodate + // new layout or invalidate requests. + if (mSelectionNotifier == null) { + mSelectionNotifier = new SelectionNotifier(); + } + post(mSelectionNotifier); + } else { + fireOnSelected(); + } + } + + // we fire selection events here not in View + if (mSelectedPosition != ListView.INVALID_POSITION && isShown() && !isInTouchMode()) { + sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_SELECTED); + } + } + + private void fireOnSelected() { + if (mOnItemSelectedListener == null) + return; + + int selection = this.getSelectedItemPosition(); + if (selection >= 0) { + View v = getSelectedView(); + mOnItemSelectedListener.onItemSelected(this, v, selection, + getAdapter().getItemId(selection)); + } else { + mOnItemSelectedListener.onNothingSelected(this); + } + } + + @Override + public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { + View selectedView = getSelectedView(); + if (selectedView != null && selectedView.getVisibility() == VISIBLE + && selectedView.dispatchPopulateAccessibilityEvent(event)) { + return true; + } + return false; + } + + @Override + public boolean onRequestSendAccessibilityEvent(View child, AccessibilityEvent event) { + if (super.onRequestSendAccessibilityEvent(child, event)) { + // Add a record for ourselves as well. + AccessibilityEvent record = AccessibilityEvent.obtain(); + onInitializeAccessibilityEvent(record); + // Populate with the text of the requesting child. + child.dispatchPopulateAccessibilityEvent(record); + event.appendRecord(record); + return true; + } + return false; + } + + @Override + public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { + super.onInitializeAccessibilityNodeInfo(info); + info.setScrollable(isScrollableForAccessibility()); + View selectedView = getSelectedView(); + if (selectedView != null) { + info.setEnabled(selectedView.isEnabled()); + } + } + + @Override + public void onInitializeAccessibilityEvent(AccessibilityEvent event) { + super.onInitializeAccessibilityEvent(event); + event.setScrollable(isScrollableForAccessibility()); + View selectedView = getSelectedView(); + if (selectedView != null) { + event.setEnabled(selectedView.isEnabled()); + } + event.setCurrentItemIndex(getSelectedItemPosition()); + event.setFromIndex(getFirstVisiblePosition()); + event.setToIndex(getLastVisiblePosition()); + event.setItemCount(getCount()); + } + + private boolean isScrollableForAccessibility() { + T adapter = getAdapter(); + if (adapter != null) { + final int itemCount = adapter.getCount(); + return itemCount > 0 + && (getFirstVisiblePosition() > 0 || getLastVisiblePosition() < itemCount - 1); + } + return false; + } + + @Override + protected boolean canAnimate() { + return super.canAnimate() && mItemCount > 0; + } + + void handleDataChanged() { + final int count = mItemCount; + boolean found = false; + + if (count > 0) { + + int newPos; + + // Find the row we are supposed to sync to + if (mNeedSync) { + // Update this first, since setNextSelectedPositionInt inspects + // it + mNeedSync = false; + + // See if we can find a position in the new data with the same + // id as the old selection + newPos = findSyncPosition(); + if (newPos >= 0) { + // Verify that new selection is selectable + int selectablePos = lookForSelectablePosition(newPos, true); + if (selectablePos == newPos) { + // Same row id is selected + setNextSelectedPositionInt(newPos); + found = true; + } + } + } + if (!found) { + // Try to use the same position if we can't find matching data + newPos = getSelectedItemPosition(); + + // Pin position to the available range + if (newPos >= count) { + newPos = count - 1; + } + if (newPos < 0) { + newPos = 0; + } + + // Make sure we select something selectable -- first look down + int selectablePos = lookForSelectablePosition(newPos, true); + if (selectablePos < 0) { + // Looking down didn't work -- try looking up + selectablePos = lookForSelectablePosition(newPos, false); + } + if (selectablePos >= 0) { + setNextSelectedPositionInt(selectablePos); + checkSelectionChanged(); + found = true; + } + } + } + if (!found) { + // Nothing is selected + mSelectedPosition = INVALID_POSITION; + mSelectedRowId = INVALID_ROW_ID; + mNextSelectedPosition = INVALID_POSITION; + mNextSelectedRowId = INVALID_ROW_ID; + mNeedSync = false; + checkSelectionChanged(); + } + } + + void checkSelectionChanged() { + if ((mSelectedPosition != mOldSelectedPosition) || (mSelectedRowId != mOldSelectedRowId)) { + selectionChanged(); + mOldSelectedPosition = mSelectedPosition; + mOldSelectedRowId = mSelectedRowId; + } + } + + /** + * Searches the adapter for a position matching mSyncRowId. The search starts at mSyncPosition + * and then alternates between moving up and moving down until 1) we find the right position, or + * 2) we run out of time, or 3) we have looked at every position + * + * @return Position of the row that matches mSyncRowId, or {@link #INVALID_POSITION} if it can't + * be found + */ + int findSyncPosition() { + int count = mItemCount; + + if (count == 0) { + return INVALID_POSITION; + } + + long idToMatch = mSyncRowId; + int seed = mSyncPosition; + + // If there isn't a selection don't hunt for it + if (idToMatch == INVALID_ROW_ID) { + return INVALID_POSITION; + } + + // Pin seed to reasonable values + seed = Math.max(0, seed); + seed = Math.min(count - 1, seed); + + long endTime = SystemClock.uptimeMillis() + SYNC_MAX_DURATION_MILLIS; + + long rowId; + + // first position scanned so far + int first = seed; + + // last position scanned so far + int last = seed; + + // True if we should move down on the next iteration + boolean next = false; + + // True when we have looked at the first item in the data + boolean hitFirst; + + // True when we have looked at the last item in the data + boolean hitLast; + + // Get the item ID locally (instead of getItemIdAtPosition), so + // we need the adapter + T adapter = getAdapter(); + if (adapter == null) { + return INVALID_POSITION; + } + + while (SystemClock.uptimeMillis() <= endTime) { + rowId = adapter.getItemId(seed); + if (rowId == idToMatch) { + // Found it! + return seed; + } + + hitLast = last == count - 1; + hitFirst = first == 0; + + if (hitLast && hitFirst) { + // Looked at everything + break; + } + + if (hitFirst || (next && !hitLast)) { + // Either we hit the top, or we are trying to move down + last++; + seed = last; + // Try going up next time + next = false; + } else if (hitLast || (!next && !hitFirst)) { + // Either we hit the bottom, or we are trying to move up + first--; + seed = first; + // Try going down next time + next = true; + } + + } + + return INVALID_POSITION; + } + + /** + * Find a position that can be selected (i.e., is not a separator). + * + * @param position The starting position to look at. + * @param lookDown Whether to look down for other positions. + * @return The next selectable position starting at position and then searching either up or + * down. Returns {@link #INVALID_POSITION} if nothing can be found. + */ + int lookForSelectablePosition(int position, boolean lookDown) { + return position; + } + + /** + * Utility to keep mSelectedPosition and mSelectedRowId in sync + * @param position Our current position + */ + void setSelectedPositionInt(int position) { + mSelectedPosition = position; + mSelectedRowId = getItemIdAtPosition(position); + } + + /** + * Utility to keep mNextSelectedPosition and mNextSelectedRowId in sync + * @param position Intended value for mSelectedPosition the next time we go + * through layout + */ + void setNextSelectedPositionInt(int position) { + mNextSelectedPosition = position; + mNextSelectedRowId = getItemIdAtPosition(position); + // If we are trying to sync to the selection, update that too + if (mNeedSync && mSyncMode == SYNC_SELECTED_POSITION && position >= 0) { + mSyncPosition = position; + mSyncRowId = mNextSelectedRowId; + } + } + + /** + * Remember enough information to restore the screen state when the data has + * changed. + * + */ + void rememberSyncState() { + if (getChildCount() > 0) { + mNeedSync = true; + mSyncHeight = mLayoutHeight; + if (mSelectedPosition >= 0) { + // Sync the selection state + View v = getChildAt(mSelectedPosition - mFirstPosition); + mSyncRowId = mNextSelectedRowId; + mSyncPosition = mNextSelectedPosition; + if (v != null) { + mSpecificTop = v.getTop(); + } + mSyncMode = SYNC_SELECTED_POSITION; + } else { + // Sync the based on the offset of the first view + View v = getChildAt(0); + T adapter = getAdapter(); + if (mFirstPosition >= 0 && mFirstPosition < adapter.getCount()) { + mSyncRowId = adapter.getItemId(mFirstPosition); + } else { + mSyncRowId = NO_ID; + } + mSyncPosition = mFirstPosition; + if (v != null) { + mSpecificTop = v.getTop(); + } + mSyncMode = SYNC_FIRST_POSITION; + } + } + } +} |