diff options
Diffstat (limited to 'android/src/com/artifex/mupdfdemo/ReaderView.java')
| -rw-r--r-- | android/src/com/artifex/mupdfdemo/ReaderView.java | 583 |
1 files changed, 583 insertions, 0 deletions
diff --git a/android/src/com/artifex/mupdfdemo/ReaderView.java b/android/src/com/artifex/mupdfdemo/ReaderView.java new file mode 100644 index 00000000..16ac1129 --- /dev/null +++ b/android/src/com/artifex/mupdfdemo/ReaderView.java @@ -0,0 +1,583 @@ +package com.artifex.mupdfdemo; + +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; + + static abstract class ViewMapper { + abstract void applyToView(View view); + } + + 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)); + } + + public void applyToChildren(ViewMapper mapper) { + for (int i = 0; i < mChildViews.size(); i++) + mapper.applyToView(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); + if (v != null) + 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(); + } + } +} |