Back to project page Munin-for-Android.
The source code is released under:
GNU General Public License
If you think the Android project Munin-for-Android listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
/* * Copyright (C) 2011 Patrik kerfeldt/* w w w . j a v a 2 s. c o m*/ * * 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 org.taptwo.android.widget; import android.annotation.SuppressLint; import android.content.Context; import android.content.res.Configuration; import android.content.res.TypedArray; import android.database.DataSetObserver; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.ViewTreeObserver.OnGlobalLayoutListener; import android.widget.AbsListView; import android.widget.Adapter; import android.widget.AdapterView; import android.widget.Scroller; import com.chteuchteu.munin.R; import java.util.EnumSet; import java.util.LinkedList; /** * A horizontally scrollable {@link ViewGroup} with items populated from an * {@link Adapter}. The ViewFlow uses a buffer to store loaded {@link View}s in. * The default size of the buffer is 3 elements on both sides of the currently * visible {@link View}, making up a total buffer size of 3 * 2 + 1 = 7. The * buffer size can be changed using the {@code sidebuffer} xml attribute. * */ public class ViewFlow extends AdapterView<Adapter> { private static final int SNAP_VELOCITY = 100; private static final int INVALID_SCREEN = -1; private final static int TOUCH_STATE_REST = 0; private final static int TOUCH_STATE_SCROLLING = 1; private LinkedList<View> mLoadedViews; private LinkedList<View> mRecycledViews; private int mCurrentBufferIndex; private int mCurrentAdapterIndex; private int mSideBuffer = 2; private Scroller mScroller; private VelocityTracker mVelocityTracker; private int mTouchState = TOUCH_STATE_REST; private float mLastMotionX; private int mTouchSlop; private int mMaximumVelocity; private int mCurrentScreen; private int mNextScreen = INVALID_SCREEN; private boolean mFirstLayout = true; private ViewSwitchListener mViewSwitchListener; private ViewLazyInitializeListener mViewInitializeListener; private EnumSet<LazyInit> mLazyInit = EnumSet.allOf(LazyInit.class); private Adapter mAdapter; private int mLastScrollDirection; private AdapterDataSetObserver mDataSetObserver; private FlowIndicator mIndicator; private int mLastOrientation = -1; private boolean animationEnabled = true; // Custom private OnGlobalLayoutListener orientationChangeListener = new OnGlobalLayoutListener() { @SuppressWarnings("deprecation") @Override public void onGlobalLayout() { getViewTreeObserver().removeGlobalOnLayoutListener( orientationChangeListener); setSelection(mCurrentAdapterIndex); } }; /** * Receives call backs when a new {@link View} has been scrolled to. */ public static interface ViewSwitchListener { /** * This method is called when a new View has been scrolled to. * * @param view * the {@link View} currently in focus. * @param position * The position in the adapter of the {@link View} currently in focus. */ void onSwitched(View view, int position); } public static interface ViewLazyInitializeListener { void onViewLazyInitialize(View view, int position); } enum LazyInit { LEFT, RIGHT } public ViewFlow(Context context) { super(context); mSideBuffer = 3; init(); } public ViewFlow(Context context, int sideBuffer) { super(context); mSideBuffer = sideBuffer; init(); } @SuppressLint("Recycle") public ViewFlow(Context context, AttributeSet attrs) { super(context, attrs); TypedArray styledAttrs = context.obtainStyledAttributes(attrs, R.styleable.ViewFlow); mSideBuffer = styledAttrs.getInt(R.styleable.ViewFlow_sidebuffer, 3); init(); } private void init() { mLoadedViews = new LinkedList<View>(); mRecycledViews = new LinkedList<View>(); mScroller = new Scroller(getContext()); final ViewConfiguration configuration = ViewConfiguration .get(getContext()); mTouchSlop = configuration.getScaledTouchSlop(); mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); } public void onConfigurationChanged(Configuration newConfig) { if (newConfig.orientation != mLastOrientation) { mLastOrientation = newConfig.orientation; getViewTreeObserver().addOnGlobalLayoutListener(orientationChangeListener); } } public int getViewsCount() { return mAdapter.getCount(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int width = MeasureSpec.getSize(widthMeasureSpec); final int widthMode = MeasureSpec.getMode(widthMeasureSpec); if (widthMode != MeasureSpec.EXACTLY && !isInEditMode()) { throw new IllegalStateException( "ViewFlow can only be used in EXACTLY mode."); } final int heightMode = MeasureSpec.getMode(heightMeasureSpec); if (heightMode != MeasureSpec.EXACTLY && !isInEditMode()) { throw new IllegalStateException( "ViewFlow can only be used in EXACTLY mode."); } // The children are given the same width and height as the workspace final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); } if (mFirstLayout) { mScroller.startScroll(0, 0, mCurrentScreen * width, 0, 0); mFirstLayout = false; } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int childLeft = 0; final int count = getChildCount(); for (int i = 0; i < count; i++) { final View child = getChildAt(i); if (child.getVisibility() != View.GONE) { final int childWidth = child.getMeasuredWidth(); child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight()); childLeft += childWidth; } } } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if (getChildCount() == 0) return false; if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); final float x = ev.getX(); switch (action) { case MotionEvent.ACTION_DOWN: /* * If being flinged and user touches, stop the fling. isFinished * will be false if being flinged. */ if (!mScroller.isFinished()) { mScroller.abortAnimation(); } // Remember where the motion event started mLastMotionX = x; mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; break; case MotionEvent.ACTION_MOVE: final int deltaX = (int) (mLastMotionX - x); boolean xMoved = Math.abs(deltaX) > mTouchSlop; if (xMoved) { // Scroll if the user moved far enough along the X axis mTouchState = TOUCH_STATE_SCROLLING; if (mViewInitializeListener != null) initializeView(deltaX); } if (mTouchState == TOUCH_STATE_SCROLLING) { // Scroll to follow the motion event mLastMotionX = x; final int scrollX = getScrollX(); if (deltaX < 0) { if (scrollX > 0) { scrollBy(Math.max(-scrollX, deltaX), 0); } } else if (deltaX > 0) { final int availableToScroll = getChildAt( getChildCount() - 1).getRight() - scrollX - getWidth(); if (availableToScroll > 0) { scrollBy(Math.min(availableToScroll, deltaX), 0); } } return true; } break; case MotionEvent.ACTION_UP: if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int velocityX = (int) velocityTracker.getXVelocity(); if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) { // Fling hard enough to move left snapToScreen(mCurrentScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) { // Fling hard enough to move right snapToScreen(mCurrentScreen + 1); } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } mTouchState = TOUCH_STATE_REST; break; case MotionEvent.ACTION_CANCEL: mTouchState = TOUCH_STATE_REST; } return false; } @Override public boolean onTouchEvent(MotionEvent ev) { if (getChildCount() == 0) return false; if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); final int action = ev.getAction(); final float x = ev.getX(); switch (action) { case MotionEvent.ACTION_DOWN: /* * If being flinged and user touches, stop the fling. isFinished * will be false if being flinged. */ if (!mScroller.isFinished()) { mScroller.abortAnimation(); } // Remember where the motion event started mLastMotionX = x; mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; break; case MotionEvent.ACTION_MOVE: final int deltaX = (int) (mLastMotionX - x); boolean xMoved = Math.abs(deltaX) > mTouchSlop; if (xMoved) { // Scroll if the user moved far enough along the X axis mTouchState = TOUCH_STATE_SCROLLING; if (mViewInitializeListener != null) initializeView(deltaX); } if (mTouchState == TOUCH_STATE_SCROLLING) { // Scroll to follow the motion event mLastMotionX = x; final int scrollX = getScrollX(); if (deltaX < 0) { if (scrollX > 0) { scrollBy(Math.max(-scrollX, deltaX), 0); } } else if (deltaX > 0) { final int availableToScroll = getChildAt( getChildCount() - 1).getRight() - scrollX - getWidth(); if (availableToScroll > 0) { scrollBy(Math.min(availableToScroll, deltaX), 0); } } return true; } break; case MotionEvent.ACTION_UP: if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int velocityX = (int) velocityTracker.getXVelocity(); if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) { // Fling hard enough to move left snapToScreen(mCurrentScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) { // Fling hard enough to move right snapToScreen(mCurrentScreen + 1); } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } mTouchState = TOUCH_STATE_REST; break; case MotionEvent.ACTION_CANCEL: snapToDestination(); mTouchState = TOUCH_STATE_REST; } return true; } private void initializeView(final float direction) { if (direction > 0) { if (mLazyInit.contains(LazyInit.RIGHT)) { mLazyInit.remove(LazyInit.RIGHT); if (mCurrentBufferIndex+1 < mLoadedViews.size()) mViewInitializeListener.onViewLazyInitialize(mLoadedViews.get(mCurrentBufferIndex + 1), mCurrentAdapterIndex + 1); } } else { if (mLazyInit.contains(LazyInit.LEFT)) { mLazyInit.remove(LazyInit.LEFT); if (mCurrentBufferIndex > 0) mViewInitializeListener.onViewLazyInitialize(mLoadedViews.get(mCurrentBufferIndex - 1), mCurrentAdapterIndex - 1); } } } @Override protected void onScrollChanged(int h, int v, int oldh, int oldv) { super.onScrollChanged(h, v, oldh, oldv); if (mIndicator != null) { /* * The actual horizontal scroll origin does typically not match the * perceived one. Therefore, we need to calculate the perceived * horizontal scroll origin here, since we use a view buffer. */ int hPerceived = h + (mCurrentAdapterIndex - mCurrentBufferIndex) * getWidth(); mIndicator.onScrolled(hPerceived, v, oldh, oldv); } } private void snapToDestination() { final int screenWidth = getWidth(); final int whichScreen = (getScrollX() + (screenWidth / 2)) / screenWidth; snapToScreen(whichScreen); } private void snapToScreen(int whichScreen) { mLastScrollDirection = whichScreen - mCurrentScreen; if (!mScroller.isFinished()) return; whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1)); mNextScreen = whichScreen; final int newX = whichScreen * getWidth(); final int delta = newX - getScrollX(); int animation_duration = Math.abs(delta)/2; if (!animationEnabled) animation_duration = 0; mScroller.startScroll(getScrollX(), 0, delta, 0, animation_duration); invalidate(); } @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } else if (mNextScreen != INVALID_SCREEN) { mCurrentScreen = Math.max(0, Math.min(mNextScreen, getChildCount() - 1)); mNextScreen = INVALID_SCREEN; postViewSwitched(mLastScrollDirection); } } /** * Scroll to the {@link View} in the view buffer specified by the index. * * @param indexInBuffer * Index of the view in the view buffer. */ private void setVisibleView(int indexInBuffer, boolean uiThread) { mCurrentScreen = Math.max(0, Math.min(indexInBuffer, getChildCount() - 1)); int dx = (mCurrentScreen * getWidth()) - mScroller.getCurrX(); mScroller.startScroll(mScroller.getCurrX(), mScroller.getCurrY(), dx, 0, 0); if(dx == 0) onScrollChanged(mScroller.getCurrX() + dx, mScroller.getCurrY(), mScroller.getCurrX() + dx, mScroller.getCurrY()); if (uiThread) invalidate(); else postInvalidate(); } /** * Set the listener that will receive notifications every time the {code * ViewFlow} scrolls. * * @param l * the scroll listener */ public void setOnViewSwitchListener(ViewSwitchListener l) { mViewSwitchListener = l; } public void setOnViewLazyInitializeListener(ViewLazyInitializeListener l) { mViewInitializeListener = l; } @Override public Adapter getAdapter() { return mAdapter; } @Override public void setAdapter(Adapter adapter) { setAdapter(adapter, 0); } public void setAnimationEnabled(boolean b) { this.animationEnabled = b; } public void setAdapter(Adapter adapter, int initialPosition) { if (mAdapter != null) { mAdapter.unregisterDataSetObserver(mDataSetObserver); } mAdapter = adapter; if (mAdapter != null) { mDataSetObserver = new AdapterDataSetObserver(); mAdapter.registerDataSetObserver(mDataSetObserver); } if (mAdapter == null || mAdapter.getCount() == 0) return; setSelection(initialPosition); } @Override public View getSelectedView() { return (mCurrentBufferIndex < mLoadedViews.size() ? mLoadedViews .get(mCurrentBufferIndex) : null); } @Override public int getSelectedItemPosition() { return mCurrentAdapterIndex; } /** * Set the FlowIndicator * * @param flowIndicator */ public void setFlowIndicator(FlowIndicator flowIndicator) { mIndicator = flowIndicator; mIndicator.setViewFlow(this); } protected void recycleViews() { while (!mLoadedViews.isEmpty()) recycleView(mLoadedViews.remove()); } protected void recycleView(View v) { if (v == null) return; mRecycledViews.addFirst(v); detachViewFromParent(v); } protected View getRecycledView() { return (mRecycledViews.isEmpty() ? null : mRecycledViews.remove()); } @Override public void setSelection(int position) { mNextScreen = INVALID_SCREEN; mScroller.forceFinished(true); if (mAdapter == null) return; position = Math.max(position, 0); position = Math.min(position, mAdapter.getCount()-1); recycleViews(); View currentView = makeAndAddView(position, true); mLoadedViews.addLast(currentView); if (mViewInitializeListener != null) mViewInitializeListener.onViewLazyInitialize(currentView, position); for(int offset = 1; mSideBuffer - offset >= 0; offset++) { int leftIndex = position - offset; int rightIndex = position + offset; if(leftIndex >= 0) mLoadedViews.addFirst(makeAndAddView(leftIndex, false)); if(rightIndex < mAdapter.getCount()) mLoadedViews.addLast(makeAndAddView(rightIndex, true)); } mCurrentBufferIndex = mLoadedViews.indexOf(currentView); mCurrentAdapterIndex = position; requestLayout(); setVisibleView(mCurrentBufferIndex, false); if (mIndicator != null) { mIndicator.onSwitched(currentView, mCurrentAdapterIndex); } if (mViewSwitchListener != null) { mViewSwitchListener.onSwitched(currentView, mCurrentAdapterIndex); } } private void resetFocus() { logBuffer(); recycleViews(); removeAllViewsInLayout(); mLazyInit.addAll(EnumSet.allOf(LazyInit.class)); for (int i = Math.max(0, mCurrentAdapterIndex - mSideBuffer); i < Math .min(mAdapter.getCount(), mCurrentAdapterIndex + mSideBuffer + 1); i++) { mLoadedViews.addLast(makeAndAddView(i, true)); if (i == mCurrentAdapterIndex) { mCurrentBufferIndex = mLoadedViews.size() - 1; if (mViewInitializeListener != null) mViewInitializeListener.onViewLazyInitialize(mLoadedViews.getLast(), mCurrentAdapterIndex); } } logBuffer(); requestLayout(); } private void postViewSwitched(int direction) { if (direction == 0) return; if (direction > 0) { // to the right mCurrentAdapterIndex++; mCurrentBufferIndex++; mLazyInit.remove(LazyInit.LEFT); mLazyInit.add(LazyInit.RIGHT); // Recycle view outside buffer range if (mCurrentAdapterIndex > mSideBuffer) { recycleView(mLoadedViews.removeFirst()); mCurrentBufferIndex--; } // Add new view to buffer int newBufferIndex = mCurrentAdapterIndex + mSideBuffer; if (newBufferIndex < mAdapter.getCount()) mLoadedViews.addLast(makeAndAddView(newBufferIndex, true)); } else { // to the left mCurrentAdapterIndex--; mCurrentBufferIndex--; mLazyInit.add(LazyInit.LEFT); mLazyInit.remove(LazyInit.RIGHT); // Recycle view outside buffer range if (mAdapter.getCount() - 1 - mCurrentAdapterIndex > mSideBuffer) { recycleView(mLoadedViews.removeLast()); } // Add new view to buffer int newBufferIndex = mCurrentAdapterIndex - mSideBuffer; if (newBufferIndex > -1) { mLoadedViews.addFirst(makeAndAddView(newBufferIndex, false)); mCurrentBufferIndex++; } } requestLayout(); setVisibleView(mCurrentBufferIndex, true); if (mIndicator != null) { try { mIndicator.onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } catch (Exception ex) { ex.printStackTrace(); } } if (mViewSwitchListener != null) { mViewSwitchListener .onSwitched(mLoadedViews.get(mCurrentBufferIndex), mCurrentAdapterIndex); } logBuffer(); } @SuppressWarnings("deprecation") private View setupChild(View child, boolean addToEnd, boolean recycle) { ViewGroup.LayoutParams p = (ViewGroup.LayoutParams) child .getLayoutParams(); if (p == null) { p = new AbsListView.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT, 0); } if (recycle) attachViewToParent(child, (addToEnd ? -1 : 0), p); else addViewInLayout(child, (addToEnd ? -1 : 0), p, true); return child; } private View makeAndAddView(int position, boolean addToEnd) { return makeAndAddView(position, addToEnd, getRecycledView()); } private View makeAndAddView(int position, boolean addToEnd, View convertView) { View view = mAdapter.getView(position, convertView, this); if(view != convertView && convertView != null) mRecycledViews.add(convertView); return setupChild(view, addToEnd, view == convertView); } class AdapterDataSetObserver extends DataSetObserver { @Override public void onChanged() { View v = getChildAt(mCurrentBufferIndex); if (v != null) { for (int index = 0; index < mAdapter.getCount(); index++) { if (v.equals(mAdapter.getItem(index))) { mCurrentAdapterIndex = index; break; } } } resetFocus(); } @Override public void onInvalidated() { // Not yet implemented! } } private void logBuffer() { /*Log.d("viewflow", "Size of mLoadedViews: " + mLoadedViews.size() + ", Size of mRecycledViews: " + mRecycledViews.size() + ", X: " + mScroller.getCurrX() + ", Y: " + mScroller.getCurrY()); Log.d("viewflow", "IndexInAdapter: " + mCurrentAdapterIndex + ", IndexInBuffer: " + mCurrentBufferIndex);*/ } }