Add pinned listview lib

1 files changed, 513 insertions, 0 deletions

diff --git a/libraries/pinned-section-listview/library/src/com/hb/views/PinnedSectionListView.java b/libraries/pinned-section-listview/library/src/com/hb/views/PinnedSectionListView.java
new file mode 100644
index 000000000..8100ad693
--- /dev/null
+++ b/libraries/pinned-section-listview/library/src/com/hb/views/PinnedSectionListView.java
@@ -0,0 +1,513 @@
+/*
+ * Copyright (C) 2013 Sergej Shafarenka, halfbit.de
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file kt 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.hb.views;
+
+import android.content.Context;
+import android.database.DataSetObserver;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.PointF;
+import android.graphics.Rect;
+import android.graphics.drawable.GradientDrawable;
+import android.graphics.drawable.GradientDrawable.Orientation;
+import android.os.Parcelable;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.view.SoundEffectConstants;
+import android.view.View;
+import android.view.ViewConfiguration;
+import android.view.accessibility.AccessibilityEvent;
+import android.widget.AbsListView;
+import android.widget.HeaderViewListAdapter;
+import android.widget.ListAdapter;
+import android.widget.ListView;
+import android.widget.SectionIndexer;
+
+import com.hb.views.pinnedsection.BuildConfig;
+
+/**
+ * ListView, which is capable to pin section views at its top while the rest is still scrolled.
+ */
+public class PinnedSectionListView extends ListView {
+
+    //-- inner classes
+
+	/** List adapter to be implemented for being used with PinnedSectionListView adapter. */
+	public static interface PinnedSectionListAdapter extends ListAdapter {
+		/** This method shall return 'true' if views of given type has to be pinned. */
+		boolean isItemViewTypePinned(int viewType);
+	}
+
+	/** Wrapper class for pinned section view and its position in the list. */
+	static class PinnedSection {
+		public View view;
+		public int position;
+		public long id;
+	}
+
+	//-- class fields
+
+    // fields used for handling touch events
+    private final Rect mTouchRect = new Rect();
+    private final PointF mTouchPoint = new PointF();
+    private int mTouchSlop;
+    private View mTouchTarget;
+    private MotionEvent mDownEvent;
+
+    // fields used for drawing shadow under a pinned section
+    private GradientDrawable mShadowDrawable;
+    private int mSectionsDistanceY;
+    private int mShadowHeight;
+
+    /** Delegating listener, can be null. */
+    OnScrollListener mDelegateOnScrollListener;
+
+    /** Shadow for being recycled, can be null. */
+    PinnedSection mRecycleSection;
+
+    /** shadow instance with a pinned view, can be null. */
+    PinnedSection mPinnedSection;
+
+    /** Pinned view Y-translation. We use it to stick pinned view to the next section. */
+    int mTranslateY;
+
+	/** Scroll listener which does the magic */
+	private final OnScrollListener mOnScrollListener = new OnScrollListener() {
+
+		@Override public void onScrollStateChanged(AbsListView view, int scrollState) {
+			if (mDelegateOnScrollListener != null) { // delegate
+				mDelegateOnScrollListener.onScrollStateChanged(view, scrollState);
+			}
+		}
+
+		@Override
+        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
+
+            if (mDelegateOnScrollListener != null) { // delegate
+                mDelegateOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
+            }
+
+            // get expected adapter or fail fast
+            ListAdapter adapter = getAdapter();
+            if (adapter == null || visibleItemCount == 0) return; // nothing to do
+
+            final boolean isFirstVisibleItemSection =
+                    isItemViewTypePinned(adapter, adapter.getItemViewType(firstVisibleItem));
+
+            if (isFirstVisibleItemSection) {
+                View sectionView = getChildAt(0);
+                if (sectionView.getTop() == getPaddingTop()) { // view sticks to the top, no need for pinned shadow
+                    destroyPinnedShadow();
+                } else { // section doesn't stick to the top, make sure we have a pinned shadow
+                    ensureShadowForPosition(firstVisibleItem, firstVisibleItem, visibleItemCount);
+                }
+
+            } else { // section is not at the first visible position
+                int sectionPosition = findCurrentSectionPosition(firstVisibleItem);
+                if (sectionPosition > -1) { // we have section position
+                    ensureShadowForPosition(sectionPosition, firstVisibleItem, visibleItemCount);
+                } else { // there is no section for the first visible item, destroy shadow
+                    destroyPinnedShadow();
+                }
+            }
+		};
+
+	};
+
+	/** Default change observer. */
+    private final DataSetObserver mDataSetObserver = new DataSetObserver() {
+        @Override public void onChanged() {
+            recreatePinnedShadow();
+        };
+        @Override public void onInvalidated() {
+            recreatePinnedShadow();
+        }
+    };
+
+	//-- constructors
+
+    public PinnedSectionListView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        initView();
+    }
+
+    public PinnedSectionListView(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        initView();
+    }
+
+    private void initView() {
+        setOnScrollListener(mOnScrollListener);
+        mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
+        initShadow(true);
+    }
+
+    //-- public API methods
+
+    public void setShadowVisible(boolean visible) {
+        initShadow(visible);
+        if (mPinnedSection != null) {
+            View v = mPinnedSection.view;
+            invalidate(v.getLeft(), v.getTop(), v.getRight(), v.getBottom() + mShadowHeight);
+        }
+    }
+
+    //-- pinned section drawing methods
+
+    public void initShadow(boolean visible) {
+        if (visible) {
+            if (mShadowDrawable == null) {
+                mShadowDrawable = new GradientDrawable(Orientation.TOP_BOTTOM,
+                        new int[] { Color.parseColor("#ffa0a0a0"), Color.parseColor("#50a0a0a0"), Color.parseColor("#00a0a0a0")});
+                mShadowHeight = (int) (8 * getResources().getDisplayMetrics().density);
+            }
+        } else {
+            if (mShadowDrawable != null) {
+                mShadowDrawable = null;
+                mShadowHeight = 0;
+            }
+        }
+    }
+
+	/** Create shadow wrapper with a pinned view for a view at given position */
+	void createPinnedShadow(int position) {
+
+		// try to recycle shadow
+		PinnedSection pinnedShadow = mRecycleSection;
+		mRecycleSection = null;
+
+		// create new shadow, if needed
+		if (pinnedShadow == null) pinnedShadow = new PinnedSection();
+		// request new view using recycled view, if such
+		View pinnedView = getAdapter().getView(position, pinnedShadow.view, PinnedSectionListView.this);
+
+		// read layout parameters
+		LayoutParams layoutParams = (LayoutParams) pinnedView.getLayoutParams();
+		if (layoutParams == null) { // create default layout params
+		    layoutParams = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
+		}
+
+		int heightMode = MeasureSpec.getMode(layoutParams.height);
+		int heightSize = MeasureSpec.getSize(layoutParams.height);
+
+		if (heightMode == MeasureSpec.UNSPECIFIED) heightMode = MeasureSpec.EXACTLY;
+
+		int maxHeight = getHeight() - getListPaddingTop() - getListPaddingBottom();
+		if (heightSize > maxHeight) heightSize = maxHeight;
+
+		// measure & layout
+		int ws = MeasureSpec.makeMeasureSpec(getWidth() - getListPaddingLeft() - getListPaddingRight(), MeasureSpec.EXACTLY);
+		int hs = MeasureSpec.makeMeasureSpec(heightSize, heightMode);
+		pinnedView.measure(ws, hs);
+		pinnedView.layout(0, 0, pinnedView.getMeasuredWidth(), pinnedView.getMeasuredHeight());
+		mTranslateY = 0;
+
+		// initialize pinned shadow
+		pinnedShadow.view = pinnedView;
+		pinnedShadow.position = position;
+		pinnedShadow.id = getAdapter().getItemId(position);
+
+		// store pinned shadow
+		mPinnedSection = pinnedShadow;
+	}
+
+	/** Destroy shadow wrapper for currently pinned view */
+	void destroyPinnedShadow() {
+	    if (mPinnedSection != null) {
+	        // keep shadow for being recycled later
+	        mRecycleSection = mPinnedSection;
+	        mPinnedSection = null;
+	    }
+	}
+
+	/** Makes sure we have an actual pinned shadow for given position. */
+    void ensureShadowForPosition(int sectionPosition, int firstVisibleItem, int visibleItemCount) {
+        if (visibleItemCount < 2) { // no need for creating shadow at all, we have a single visible item
+            destroyPinnedShadow();
+            return;
+        }
+
+        if (mPinnedSection != null
+                && mPinnedSection.position != sectionPosition) { // invalidate shadow, if required
+            destroyPinnedShadow();
+        }
+
+        if (mPinnedSection == null) { // create shadow, if empty
+            createPinnedShadow(sectionPosition);
+        }
+
+        // align shadow according to next section position, if needed
+        int nextPosition = sectionPosition + 1;
+        if (nextPosition < getCount()) {
+            int nextSectionPosition = findFirstVisibleSectionPosition(nextPosition,
+                    visibleItemCount - (nextPosition - firstVisibleItem));
+            if (nextSectionPosition > -1) {
+                View nextSectionView = getChildAt(nextSectionPosition - firstVisibleItem);
+                final int bottom = mPinnedSection.view.getBottom() + getPaddingTop();
+                mSectionsDistanceY = nextSectionView.getTop() - bottom;
+                if (mSectionsDistanceY < 0) {
+                    // next section overlaps pinned shadow, move it up
+                    mTranslateY = mSectionsDistanceY;
+                } else {
+                    // next section does not overlap with pinned, stick to top
+                    mTranslateY = 0;
+                }
+            } else {
+                // no other sections are visible, stick to top
+                mTranslateY = 0;
+                mSectionsDistanceY = Integer.MAX_VALUE;
+            }
+        }
+
+    }
+
+	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 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
+	}
+
+	void recreatePinnedShadow() {
+	    destroyPinnedShadow();
+        ListAdapter adapter = getAdapter();
+        if (adapter != null && adapter.getCount() > 0) {
+            int firstVisiblePosition = getFirstVisiblePosition();
+            int sectionPosition = findCurrentSectionPosition(firstVisiblePosition);
+            if (sectionPosition == -1) return; // no views to pin, exit
+            ensureShadowForPosition(sectionPosition,
+                    firstVisiblePosition, getLastVisiblePosition() - firstVisiblePosition);
+        }
+	}
+
+	@Override
+	public void setOnScrollListener(OnScrollListener listener) {
+		if (listener == mOnScrollListener) {
+			super.setOnScrollListener(listener);
+		} else {
+			mDelegateOnScrollListener = listener;
+		}
+	}
+
+	@Override
+	public void onRestoreInstanceState(Parcelable state) {
+		super.onRestoreInstanceState(state);
+		post(new Runnable() {
+			@Override public void run() { // restore pinned view after configuration change
+			    recreatePinnedShadow();
+			}
+		});
+	}
+
+	@Override
+	public void setAdapter(ListAdapter adapter) {
+
+	    // assert adapter in debug mode
+		if (BuildConfig.DEBUG && adapter != null) {
+			if (!(adapter instanceof PinnedSectionListAdapter))
+				throw new IllegalArgumentException("Does your adapter implement PinnedSectionListAdapter?");
+			if (adapter.getViewTypeCount() < 2)
+				throw new IllegalArgumentException("Does your adapter handle at least two types" +
+						" of views in getViewTypeCount() method: items and sections?");
+		}
+
+		// unregister observer at old adapter and register on new one
+		ListAdapter oldAdapter = getAdapter();
+		if (oldAdapter != null) oldAdapter.unregisterDataSetObserver(mDataSetObserver);
+		if (adapter != null) adapter.registerDataSetObserver(mDataSetObserver);
+
+		// destroy pinned shadow, if new adapter is not same as old one
+		if (oldAdapter != adapter) destroyPinnedShadow();
+
+		super.setAdapter(adapter);
+	}
+
+	@Override
+	protected void onLayout(boolean changed, int l, int t, int r, int b) {
+	    super.onLayout(changed, l, t, r, b);
+        if (mPinnedSection != null) {
+            int parentWidth = r - l - getPaddingLeft() - getPaddingRight();
+            int shadowWidth = mPinnedSection.view.getWidth();
+            if (parentWidth != shadowWidth) {
+                recreatePinnedShadow();
+            }
+        }
+	}
+
+	@Override
+	protected void dispatchDraw(Canvas canvas) {
+		super.dispatchDraw(canvas);
+
+		if (mPinnedSection != null) {
+
+			// prepare variables
+			int pLeft = getListPaddingLeft();
+			int pTop = getListPaddingTop();
+			View view = mPinnedSection.view;
+
+			// draw child
+			canvas.save();
+
+			int clipHeight = view.getHeight() +
+			        (mShadowDrawable == null ? 0 : Math.min(mShadowHeight, mSectionsDistanceY));
+			canvas.clipRect(pLeft, pTop, pLeft + view.getWidth(), pTop + clipHeight);
+
+			canvas.translate(pLeft, pTop + mTranslateY);
+			drawChild(canvas, mPinnedSection.view, getDrawingTime());
+
+			if (mShadowDrawable != null && mSectionsDistanceY > 0) {
+			    mShadowDrawable.setBounds(mPinnedSection.view.getLeft(),
+			            mPinnedSection.view.getBottom(),
+			            mPinnedSection.view.getRight(),
+			            mPinnedSection.view.getBottom() + mShadowHeight);
+			    mShadowDrawable.draw(canvas);
+			}
+
+			canvas.restore();
+		}
+	}
+
+	//-- touch handling methods
+
+    @Override
+    public boolean dispatchTouchEvent(MotionEvent ev) {
+
+        final float x = ev.getX();
+        final float y = ev.getY();
+        final int action = ev.getAction();
+
+        if (action == MotionEvent.ACTION_DOWN
+                && mTouchTarget == null
+                && mPinnedSection != null
+                && isPinnedViewTouched(mPinnedSection.view, x, y)) { // create touch target
+
+            // user touched pinned view
+            mTouchTarget = mPinnedSection.view;
+            mTouchPoint.x = x;
+            mTouchPoint.y = y;
+
+            // copy down event for eventually be used later
+            mDownEvent = MotionEvent.obtain(ev);
+        }
+
+        if (mTouchTarget != null) {
+            if (isPinnedViewTouched(mTouchTarget, x, y)) { // forward event to pinned view
+                mTouchTarget.dispatchTouchEvent(ev);
+            }
+
+            if (action == MotionEvent.ACTION_UP) { // perform onClick on pinned view
+                super.dispatchTouchEvent(ev);
+                performPinnedItemClick();
+                clearTouchTarget();
+
+            } else if (action == MotionEvent.ACTION_CANCEL) { // cancel
+                clearTouchTarget();
+
+            } else if (action == MotionEvent.ACTION_MOVE) {
+                if (Math.abs(y - mTouchPoint.y) > mTouchSlop) {
+
+                    // cancel sequence on touch target
+                    MotionEvent event = MotionEvent.obtain(ev);
+                    event.setAction(MotionEvent.ACTION_CANCEL);
+                    mTouchTarget.dispatchTouchEvent(event);
+                    event.recycle();
+
+                    // provide correct sequence to super class for further handling
+                    super.dispatchTouchEvent(mDownEvent);
+                    super.dispatchTouchEvent(ev);
+                    clearTouchTarget();
+
+                }
+            }
+
+            return true;
+        }
+
+        // call super if this was not our pinned view
+        return super.dispatchTouchEvent(ev);
+    }
+
+    private boolean isPinnedViewTouched(View view, float x, float y) {
+        view.getHitRect(mTouchRect);
+
+        // by taping top or bottom padding, the list performs on click on a border item.
+        // we don't add top padding here to keep behavior consistent.
+        mTouchRect.top += mTranslateY;
+
+        mTouchRect.bottom += mTranslateY + getPaddingTop();
+        mTouchRect.left += getPaddingLeft();
+        mTouchRect.right -= getPaddingRight();
+        return mTouchRect.contains((int)x, (int)y);
+    }
+
+    private void clearTouchTarget() {
+        mTouchTarget = null;
+        if (mDownEvent != null) {
+            mDownEvent.recycle();
+            mDownEvent = null;
+        }
+    }
+
+    private boolean performPinnedItemClick() {
+        if (mPinnedSection == null) return false;
+
+        OnItemClickListener listener = getOnItemClickListener();
+        if (listener != null) {
+            View view =  mPinnedSection.view;
+            playSoundEffect(SoundEffectConstants.CLICK);
+            if (view != null) {
+                view.sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);
+            }
+            listener.onItemClick(this, view, mPinnedSection.position, mPinnedSection.id);
+            return true;
+        }
+        return false;
+    }
+
+    public static boolean isItemViewTypePinned(ListAdapter adapter, int viewType) {
+        if (adapter instanceof HeaderViewListAdapter) {
+            adapter = ((HeaderViewListAdapter)adapter).getWrappedAdapter();
+        }
+        return ((PinnedSectionListAdapter) adapter).isItemViewTypePinned(viewType);
+    }
+
+}