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GNU General Public License
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package com.artifex.mupdf; //from www . j av a2s.c o m import java.util.LinkedList; import java.util.NoSuchElementException; import android.content.Context; import android.graphics.Point; import android.graphics.Rect; import android.util.AttributeSet; import android.util.SparseArray; import android.view.GestureDetector; import android.view.MotionEvent; import android.view.ScaleGestureDetector; import android.view.View; import android.widget.Adapter; import android.widget.AdapterView; import android.widget.Scroller; public class ReaderView extends AdapterView<Adapter> implements GestureDetector.OnGestureListener, ScaleGestureDetector.OnScaleGestureListener, Runnable { private static final int MOVING_DIAGONALLY = 0; private static final int MOVING_LEFT = 1; private static final int MOVING_RIGHT = 2; private static final int MOVING_UP = 3; private static final int MOVING_DOWN = 4; private static final int FLING_MARGIN = 100; private static final int GAP = 20; private static final float MIN_SCALE = 1.0f; private static final float MAX_SCALE = 5.0f; private Adapter mAdapter; private int mCurrent; // Adapter's index for the current view private boolean mResetLayout; private final SparseArray<View> mChildViews = new SparseArray<View>(3); // Shadows the children of the adapter view // but with more sensible indexing private final LinkedList<View> mViewCache = new LinkedList<View>(); private boolean mUserInteracting; // Whether the user is interacting private boolean mScaling; // Whether the user is currently pinch zooming private float mScale = 1.0f; private int mXScroll; // Scroll amounts recorded from events. private int mYScroll; // and then accounted for in onLayout private final GestureDetector mGestureDetector; private final ScaleGestureDetector mScaleGestureDetector; private final Scroller mScroller; private int mScrollerLastX; private int mScrollerLastY; private boolean mScrollDisabled; public ReaderView(Context context) { super(context); mGestureDetector = new GestureDetector(this); mScaleGestureDetector = new ScaleGestureDetector(context, this); mScroller = new Scroller(context); } public ReaderView(Context context, AttributeSet attrs) { super(context, attrs); mGestureDetector = new GestureDetector(this); mScaleGestureDetector = new ScaleGestureDetector(context, this); mScroller = new Scroller(context); } public ReaderView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mGestureDetector = new GestureDetector(this); mScaleGestureDetector = new ScaleGestureDetector(context, this); mScroller = new Scroller(context); } public int getDisplayedViewIndex() { return mCurrent; } public void setDisplayedViewIndex(int i) { if (0 <= i && i < mAdapter.getCount()) { mCurrent = i; onMoveToChild(i); mResetLayout = true; requestLayout(); } } public void moveToNext() { View v = mChildViews.get(mCurrent+1); if (v != null) slideViewOntoScreen(v); } public void moveToPrevious() { View v = mChildViews.get(mCurrent-1); if (v != null) slideViewOntoScreen(v); } public void resetupChildren() { for (int i = 0; i < mChildViews.size(); i++) onChildSetup(mChildViews.keyAt(i), mChildViews.valueAt(i)); } protected void onChildSetup(int i, View v) {} protected void onMoveToChild(int i) {} protected void onSettle(View v) {}; protected void onUnsettle(View v) {}; protected void onNotInUse(View v) {}; public View getDisplayedView() { return mChildViews.get(mCurrent); } public void run() { if (!mScroller.isFinished()) { mScroller.computeScrollOffset(); int x = mScroller.getCurrX(); int y = mScroller.getCurrY(); mXScroll += x - mScrollerLastX; mYScroll += y - mScrollerLastY; mScrollerLastX = x; mScrollerLastY = y; requestLayout(); post(this); } else if (!mUserInteracting) { // End of an inertial scroll and the user is not interacting. // The layout is stable View v = mChildViews.get(mCurrent); postSettle(v); } } public boolean onDown(MotionEvent arg0) { mScroller.forceFinished(true); return true; } public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { if (mScrollDisabled) return true; View v = mChildViews.get(mCurrent); if (v != null) { Rect bounds = getScrollBounds(v); switch(directionOfTravel(velocityX, velocityY)) { case MOVING_LEFT: if (bounds.left >= 0) { // Fling off to the left bring next view onto screen View vl = mChildViews.get(mCurrent+1); if (vl != null) { slideViewOntoScreen(vl); return true; } } break; case MOVING_RIGHT: if (bounds.right <= 0) { // Fling off to the right bring previous view onto screen View vr = mChildViews.get(mCurrent-1); if (vr != null) { slideViewOntoScreen(vr); return true; } } break; } mScrollerLastX = mScrollerLastY = 0; // If the page has been dragged out of bounds then we want to spring back // nicely. fling jumps back into bounds instantly, so we don't want to use // fling in that case. On the other hand, we don't want to forgo a fling // just because of a slightly off-angle drag taking us out of bounds other // than in the direction of the drag, so we test for out of bounds only // in the direction of travel. // // Also don't fling if out of bounds in any direction by more than fling // margin Rect expandedBounds = new Rect(bounds); expandedBounds.inset(-FLING_MARGIN, -FLING_MARGIN); if(withinBoundsInDirectionOfTravel(bounds, velocityX, velocityY) && expandedBounds.contains(0, 0)) { mScroller.fling(0, 0, (int)velocityX, (int)velocityY, bounds.left, bounds.right, bounds.top, bounds.bottom); post(this); } } return true; } public void onLongPress(MotionEvent e) { } public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { if (!mScrollDisabled) { mXScroll -= distanceX; mYScroll -= distanceY; requestLayout(); } return true; } public void onShowPress(MotionEvent e) { } public boolean onSingleTapUp(MotionEvent e) { return false; } public boolean onScale(ScaleGestureDetector detector) { float previousScale = mScale; mScale = Math.min(Math.max(mScale * detector.getScaleFactor(), MIN_SCALE), MAX_SCALE); float factor = mScale/previousScale; View v = mChildViews.get(mCurrent); if (v != null) { // Work out the focus point relative to the view top left int viewFocusX = (int)detector.getFocusX() - (v.getLeft() + mXScroll); int viewFocusY = (int)detector.getFocusY() - (v.getTop() + mYScroll); // Scroll to maintain the focus point mXScroll += viewFocusX - viewFocusX * factor; mYScroll += viewFocusY - viewFocusY * factor; requestLayout(); } return true; } public boolean onScaleBegin(ScaleGestureDetector detector) { mScaling = true; // Ignore any scroll amounts yet to be accounted for: the // screen is not showing the effect of them, so they can // only confuse the user mXScroll = mYScroll = 0; // Avoid jump at end of scaling by disabling scrolling // until the next start of gesture mScrollDisabled = true; return true; } public void onScaleEnd(ScaleGestureDetector detector) { mScaling = false; } @Override public boolean onTouchEvent(MotionEvent event) { mScaleGestureDetector.onTouchEvent(event); if (!mScaling) mGestureDetector.onTouchEvent(event); if (event.getActionMasked() == MotionEvent.ACTION_DOWN) { mUserInteracting = true; } if (event.getActionMasked() == MotionEvent.ACTION_UP) { mScrollDisabled = false; mUserInteracting = false; View v = mChildViews.get(mCurrent); if (v != null) { if (mScroller.isFinished()) { // If, at the end of user interaction, there is no // current inertial scroll in operation then animate // the view onto screen if necessary slideViewOntoScreen(v); } if (mScroller.isFinished()) { // If still there is no inertial scroll in operation // then the layout is stable postSettle(v); } } } requestLayout(); return true; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int n = getChildCount(); for (int i = 0; i < n; i++) measureView(getChildAt(i)); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); View cv = mChildViews.get(mCurrent); Point cvOffset; if (!mResetLayout) { // Move to next or previous if current is sufficiently off center if (cv != null) { cvOffset = subScreenSizeOffset(cv); // cv.getRight() may be out of date with the current scale // so add left to the measured width for the correct position if (cv.getLeft() + cv.getMeasuredWidth() + cvOffset.x + GAP/2 + mXScroll < getWidth()/2 && mCurrent + 1 < mAdapter.getCount()) { postUnsettle(cv); // post to invoke test for end of animation // where we must set hq area for the new current view post(this); mCurrent++; onMoveToChild(mCurrent); } if (cv.getLeft() - cvOffset.x - GAP/2 + mXScroll >= getWidth()/2 && mCurrent > 0) { postUnsettle(cv); // post to invoke test for end of animation // where we must set hq area for the new current view post(this); mCurrent--; onMoveToChild(mCurrent); } } // Remove not needed children and hold them for reuse int numChildren = mChildViews.size(); int childIndices[] = new int[numChildren]; for (int i = 0; i < numChildren; i++) childIndices[i] = mChildViews.keyAt(i); for (int i = 0; i < numChildren; i++) { int ai = childIndices[i]; if (ai < mCurrent - 1 || ai > mCurrent + 1) { View v = mChildViews.get(ai); onNotInUse(v); mViewCache.add(v); removeViewInLayout(v); mChildViews.remove(ai); } } } else { mResetLayout = false; mXScroll = mYScroll = 0; // Remove all children and hold them for reuse int numChildren = mChildViews.size(); for (int i = 0; i < numChildren; i++) { View v = mChildViews.valueAt(i); onNotInUse(v); mViewCache.add(v); removeViewInLayout(v); } mChildViews.clear(); // post to ensure generation of hq area post(this); } // Ensure current view is present int cvLeft, cvRight, cvTop, cvBottom; boolean notPresent = (mChildViews.get(mCurrent) == null); cv = getOrCreateChild(mCurrent); // When the view is sub-screen-size in either dimension we // offset it to center within the screen area, and to keep // the views spaced out cvOffset = subScreenSizeOffset(cv); if (notPresent) { //Main item not already present. Just place it top left cvLeft = cvOffset.x; cvTop = cvOffset.y; } else { // Main item already present. Adjust by scroll offsets cvLeft = cv.getLeft() + mXScroll; cvTop = cv.getTop() + mYScroll; } // Scroll values have been accounted for mXScroll = mYScroll = 0; cvRight = cvLeft + cv.getMeasuredWidth(); cvBottom = cvTop + cv.getMeasuredHeight(); if (!mUserInteracting && mScroller.isFinished()) { Point corr = getCorrection(getScrollBounds(cvLeft, cvTop, cvRight, cvBottom)); cvRight += corr.x; cvLeft += corr.x; cvTop += corr.y; cvBottom += corr.y; } else if (cv.getMeasuredHeight() <= getHeight()) { // When the current view is as small as the screen in height, clamp // it vertically Point corr = getCorrection(getScrollBounds(cvLeft, cvTop, cvRight, cvBottom)); cvTop += corr.y; cvBottom += corr.y; } cv.layout(cvLeft, cvTop, cvRight, cvBottom); if (mCurrent > 0) { View lv = getOrCreateChild(mCurrent - 1); Point leftOffset = subScreenSizeOffset(lv); int gap = leftOffset.x + GAP + cvOffset.x; lv.layout(cvLeft - lv.getMeasuredWidth() - gap, (cvBottom + cvTop - lv.getMeasuredHeight())/2, cvLeft - gap, (cvBottom + cvTop + lv.getMeasuredHeight())/2); } if (mCurrent + 1 < mAdapter.getCount()) { View rv = getOrCreateChild(mCurrent + 1); Point rightOffset = subScreenSizeOffset(rv); int gap = cvOffset.x + GAP + rightOffset.x; rv.layout(cvRight + gap, (cvBottom + cvTop - rv.getMeasuredHeight())/2, cvRight + rv.getMeasuredWidth() + gap, (cvBottom + cvTop + rv.getMeasuredHeight())/2); } invalidate(); } @Override public Adapter getAdapter() { return mAdapter; } @Override public View getSelectedView() { throw new UnsupportedOperationException("Not supported"); } @Override public void setAdapter(Adapter adapter) { mAdapter = adapter; mChildViews.clear(); removeAllViewsInLayout(); requestLayout(); } @Override public void setSelection(int arg0) { throw new UnsupportedOperationException("Not supported"); } private View getCached() { if (mViewCache.size() == 0) return null; else return mViewCache.removeFirst(); } private View getOrCreateChild(int i) { View v = mChildViews.get(i); if (v == null) { v = mAdapter.getView(i, getCached(), this); addAndMeasureChild(i, v); } onChildSetup(i, v); return v; } private void addAndMeasureChild(int i, View v) { LayoutParams params = v.getLayoutParams(); if (params == null) { params = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); } addViewInLayout(v, 0, params, true); mChildViews.append(i, v); // Record the view against it's adapter index measureView(v); } private void measureView(View v) { // See what size the view wants to be v.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED); // Work out a scale that will fit it to this view float scale = Math.min((float)getWidth()/(float)v.getMeasuredWidth(), (float)getHeight()/(float)v.getMeasuredHeight()); // Use the fitting values scaled by our current scale factor v.measure(View.MeasureSpec.EXACTLY | (int)(v.getMeasuredWidth()*scale*mScale), View.MeasureSpec.EXACTLY | (int)(v.getMeasuredHeight()*scale*mScale)); } private Rect getScrollBounds(int left, int top, int right, int bottom) { int xmin = getWidth() - right; int xmax = -left; int ymin = getHeight() - bottom; int ymax = -top; // In either dimension, if view smaller than screen then // constrain it to be central if (xmin > xmax) xmin = xmax = (xmin + xmax)/2; if (ymin > ymax) ymin = ymax = (ymin + ymax)/2; return new Rect(xmin, ymin, xmax, ymax); } private Rect getScrollBounds(View v) { // There can be scroll amounts not yet accounted for in // onLayout, so add mXScroll and mYScroll to the current // positions when calculating the bounds. return getScrollBounds(v.getLeft() + mXScroll, v.getTop() + mYScroll, v.getLeft() + v.getMeasuredWidth() + mXScroll, v.getTop() + v.getMeasuredHeight() + mYScroll); } private Point getCorrection(Rect bounds) { return new Point(Math.min(Math.max(0,bounds.left),bounds.right), Math.min(Math.max(0,bounds.top),bounds.bottom)); } private void postSettle(final View v) { // onSettle and onUnsettle are posted so that the calls // wont be executed until after the system has performed // layout. post (new Runnable() { public void run () { onSettle(v); } }); } private void postUnsettle(final View v) { post (new Runnable() { public void run () { onUnsettle(v); } }); } private void slideViewOntoScreen(View v) { Point corr = getCorrection(getScrollBounds(v)); if (corr.x != 0 || corr.y != 0) { mScrollerLastX = mScrollerLastY = 0; mScroller.startScroll(0, 0, corr.x, corr.y, 400); post(this); } } private Point subScreenSizeOffset(View v) { return new Point(Math.max((getWidth() - v.getMeasuredWidth())/2, 0), Math.max((getHeight() - v.getMeasuredHeight())/2, 0)); } private static int directionOfTravel(float vx, float vy) { if (Math.abs(vx) > 2 * Math.abs(vy)) return (vx > 0) ? MOVING_RIGHT : MOVING_LEFT; else if (Math.abs(vy) > 2 * Math.abs(vx)) return (vy > 0) ? MOVING_DOWN : MOVING_UP; else return MOVING_DIAGONALLY; } private static boolean withinBoundsInDirectionOfTravel(Rect bounds, float vx, float vy) { switch (directionOfTravel(vx, vy)) { case MOVING_DIAGONALLY: return bounds.contains(0, 0); case MOVING_LEFT: return bounds.left <= 0; case MOVING_RIGHT: return bounds.right >= 0; case MOVING_UP: return bounds.top <= 0; case MOVING_DOWN: return bounds.bottom >= 0; default: throw new NoSuchElementException(); } } }