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package com.flavienlaurent.vdh; //from w w w.ja v a2s. co m import android.content.Context; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.VelocityTrackerCompat; import android.support.v4.view.ViewCompat; import android.support.v4.widget.ViewDragHelper; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewGroup; /** * Created by Flavien Laurent (flavienlaurent.com) on 23/08/13. */ public class YoutubeLayout extends ViewGroup { private final ViewDragHelper mDragHelper; private View mHeaderView; private View mDescView; private float mInitialMotionX; private float mInitialMotionY; private VelocityTracker mVelocityTracker = null; private int mVerticalDragRange; private int mHorizontalDragRange; private int mTop; private float mDragOffset; private boolean mIsMaximized = true; private Context mContext; public YoutubeLayout(Context context) { this(context, null); } public YoutubeLayout(Context context, AttributeSet attrs) { this(context, attrs, 0); } /** * to use in an xml definition * * @param context * @param attrs * @param defStyle */ public YoutubeLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mContext = context; mDragHelper = ViewDragHelper.create(this, 1f, new DragHelperCallback()); } @Override protected void onFinishInflate() { mHeaderView = findViewById(R.id.header); mDescView = findViewById(R.id.desc); } public void maximize() { if (smoothVerticalSlideTo(0f)) mIsMaximized = true; } public void minimize() { if (smoothVerticalSlideTo(1f)) mIsMaximized = false; } boolean smoothVerticalSlideTo(float slideOffset) { final int topBound = getPaddingTop(); int y = (int) (topBound + slideOffset * mVerticalDragRange); if (mDragHelper .smoothSlideViewTo(mHeaderView, mHeaderView.getLeft(), y)) { ViewCompat.postInvalidateOnAnimation(this); return true; } return false; } boolean smoothHorizontalSlideTo(float slideOffset) { return false; } private class DragHelperCallback extends ViewDragHelper.Callback { @Override public boolean tryCaptureView(View child, int pointerId) { return child == mHeaderView; } @Override public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) { mTop = top; mDragOffset = (float) top / mVerticalDragRange; mHeaderView.setPivotX(mHeaderView.getWidth()); mHeaderView.setPivotY(mHeaderView.getHeight()); mHeaderView.setScaleX(1 - mDragOffset / 2); mHeaderView.setScaleY(1 - mDragOffset / 2); mDescView.setAlpha(1 - mDragOffset); requestLayout(); } @Override public void onViewReleased(View releasedChild, float xvel, float yvel) { int top = getPaddingTop(); if (yvel > 0 || (yvel == 0 && mDragOffset > 0.5f)) { top += mVerticalDragRange; } mDragHelper.settleCapturedViewAt(releasedChild.getLeft(), top); invalidate(); } @Override public int getViewVerticalDragRange(View child) { return mVerticalDragRange; } @Override public int getViewHorizontalDragRange(View child) { return mHorizontalDragRange; } @Override public int clampViewPositionVertical(View child, int top, int dy) { final int topBound = getPaddingTop(); final int bottomBound = getHeight() - mHeaderView.getHeight() - mHeaderView.getPaddingBottom(); final int newTop = Math.min(Math.max(top, topBound), bottomBound); return newTop; } @Override public int clampViewPositionHorizontal(View child, int left, int dx) { final int leftBound = getPaddingLeft(); final int rightBound = getWidth() - mHeaderView.getWidth(); final int newLeft = Math.min(Math.max(left, leftBound), rightBound); return newLeft; } } @Override public void computeScroll() { if (mDragHelper.continueSettling(true)) { ViewCompat.postInvalidateOnAnimation(this); } } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { final int action = MotionEventCompat.getActionMasked(ev); if ((action != MotionEvent.ACTION_DOWN)) { mDragHelper.cancel(); return super.onInterceptTouchEvent(ev); } if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) { mDragHelper.cancel(); return false; } final float x = ev.getX(); final float y = ev.getY(); boolean interceptTap = false; switch (action) { case MotionEvent.ACTION_DOWN: { mInitialMotionX = x; mInitialMotionY = y; interceptTap = mDragHelper.isViewUnder(mHeaderView, (int) x, (int) y); break; } case MotionEvent.ACTION_MOVE: { final float adx = Math.abs(x - mInitialMotionX); final float ady = Math.abs(y - mInitialMotionY); final int slop = mDragHelper.getTouchSlop(); /* useless */ if (ady > slop && adx > ady) { mDragHelper.cancel(); return false; } } } return !(mDragHelper.shouldInterceptTouchEvent(ev) || interceptTap); } float vX = 0, vY = 0; @Override public boolean onTouchEvent(MotionEvent ev) { mDragHelper.processTouchEvent(ev); final int action = ev.getAction(); final float x = ev.getX(); final float y = ev.getY(); final int index = ev.getActionIndex(); final int pointerId = ev.getPointerId(index); boolean isHeaderViewUnder = mDragHelper.isViewUnder(mHeaderView, (int) x, (int) y); switch (action & MotionEventCompat.ACTION_MASK) { case MotionEvent.ACTION_DOWN: if (mVelocityTracker == null) mVelocityTracker = VelocityTracker.obtain(); else { // Reset the velocity tracker back to its initial state. mVelocityTracker.clear(); } // Add a user's movement to the tracker. mVelocityTracker.addMovement(ev); mInitialMotionX = x; mInitialMotionY = y; break; case MotionEvent.ACTION_MOVE: mVelocityTracker.addMovement(ev); // When you want to determine the velocity, call // computeCurrentVelocity(). Then call getXVelocity() // and getYVelocity() to retrieve the velocity for each pointer ID. mVelocityTracker.computeCurrentVelocity(1000); // Log velocity of pixels per second // Best practice to use VelocityTrackerCompat where possible. vX = VelocityTrackerCompat .getXVelocity(mVelocityTracker, pointerId); vY = VelocityTrackerCompat .getYVelocity(mVelocityTracker, pointerId); break; case MotionEvent.ACTION_UP: Log.d("", "X velocity: " + vX); Log.d("", "Y velocity: " + vY); final float dx = x - mInitialMotionX; final float dy = y - mInitialMotionY; final int slop = mDragHelper.getTouchSlop(); if (isHeaderViewUnder) { if (dx * dx + dy * dy < slop * slop) { if (mLayoutListener != null) mLayoutListener.onHeadViewClickListener(mHeaderView); } else { if (vY > 0) { minimize(); } else { maximize(); } } } break; } return isHeaderViewUnder && isViewHit(mHeaderView, (int) x, (int) y) || isViewHit(mDescView, (int) x, (int) y); } private boolean isViewHit(View view, int x, int y) { int[] viewLocation = new int[2]; view.getLocationOnScreen(viewLocation); int[] parentLocation = new int[2]; this.getLocationOnScreen(parentLocation); int screenX = parentLocation[0] + x; int screenY = parentLocation[1] + y; return screenX >= viewLocation[0] && screenX < viewLocation[0] + view.getWidth() && screenY >= viewLocation[1] && screenY < viewLocation[1] + view.getHeight(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { measureChildren(widthMeasureSpec, heightMeasureSpec); int maxWidth = MeasureSpec.getSize(widthMeasureSpec); int maxHeight = MeasureSpec.getSize(heightMeasureSpec); setMeasuredDimension( resolveSizeAndState(maxWidth, widthMeasureSpec, 0), resolveSizeAndState(maxHeight, heightMeasureSpec, 0)); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { mVerticalDragRange = getHeight() - mHeaderView.getHeight(); mHorizontalDragRange = mDescView.getWidth(); mHeaderView.layout(0, mTop, r, mTop + mHeaderView.getMeasuredHeight()); mDescView .layout(0, mTop + mHeaderView.getMeasuredHeight(), r, mTop + b); if (mTop + mHeaderView.getMeasuredHeight() >= getHeight()) { // TODO } else { // TODO } } private YoutubeLayoutListener mLayoutListener; public void setYoutubeLayoutListener(YoutubeLayoutListener listener) { this.mLayoutListener = listener; } public interface YoutubeLayoutListener { public void onHeadViewClickListener(View view); } }