android.widget.Scroller Java Examples

private void init() {
	final Context context = getContext();
	final ViewConfiguration configuration = ViewConfiguration.get(context);

	mScroller = new Scroller(context, flipInterpolator);
	mTouchSlop = configuration.getScaledPagingTouchSlop();
	mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
	mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();

	mShadowPaint.setColor(Color.BLACK);
	mShadowPaint.setStyle(Style.FILL);
	mShadePaint.setColor(Color.BLACK);
	mShadePaint.setStyle(Style.FILL);
	mShinePaint.setColor(Color.WHITE);
	mShinePaint.setStyle(Style.FILL);
}
 

/**
 * Apps should use ViewDragHelper.create() to get a new instance.
 * This will allow VDH to use internal compatibility implementations for different
 * platform versions.
 *
 * @param context Context to initialize config-dependent params from
 * @param forParent Parent view to monitor
 */
private ViewDragHelper(Context context, ViewGroup forParent, Callback cb) {
	if (forParent == null) {
		throw new IllegalArgumentException("Parent view may not be null");
	}
	if (cb == null) {
		throw new IllegalArgumentException("Callback may not be null");
	}

	mParentView = forParent;
	mCallback = cb;

	final ViewConfiguration vc = ViewConfiguration.get(context);
	final float density = context.getResources().getDisplayMetrics().density;
	mEdgeSize = (int) (EDGE_SIZE * density + 0.5f);

	mTouchSlop = vc.getScaledTouchSlop();
	mMaxVelocity = vc.getScaledMaximumFlingVelocity();
	mMinVelocity = vc.getScaledMinimumFlingVelocity();
	mScroller = new Scroller(context, sInterpolator);
}
 

private void init() {
    final Context context = getContext();
    final ViewConfiguration configuration = ViewConfiguration.get(context);

    mScroller = new Scroller(context, flipInterpolator);
    mTouchSlop = configuration.getScaledPagingTouchSlop();
    mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
    mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();

    mShadowPaint.setColor(Color.BLACK);
    mShadowPaint.setStyle(Style.FILL);
    mShadePaint.setColor(Color.BLACK);
    mShadePaint.setStyle(Style.FILL);
    mShinePaint.setColor(Color.WHITE);
    mShinePaint.setStyle(Style.FILL);
}
 

/**
 * Move to the final position of a scroller. Ensures to force finish the scroller
 * and if it is not at its final position a scroll of the selector wheel is
 * performed to fast forward to the final position.
 *
 * @param scroller The scroller to whose final position to get.
 * @return True of the a move was performed, i.e. the scroller was not in final position.
 */
private boolean moveToFinalScrollerPosition(Scroller scroller) {
    scroller.forceFinished(true);
    int amountToScroll = scroller.getFinalY() - scroller.getCurrY();
    int futureScrollOffset = (mCurrentScrollOffset + amountToScroll) % mSelectorElementHeight;
    int overshootAdjustment = mInitialScrollOffset - futureScrollOffset;
    if (overshootAdjustment != 0) {
        if (Math.abs(overshootAdjustment) > mSelectorElementHeight / 2) {
            if (overshootAdjustment > 0) {
                overshootAdjustment -= mSelectorElementHeight;
            } else {
                overshootAdjustment += mSelectorElementHeight;
            }
        }
        amountToScroll += overshootAdjustment;
        scrollBy(0, amountToScroll);
        return true;
    }
    return false;
}
 

/**
 * 通过scrollTo方法完成协调布局的滑动，其中主要使用了ViewCompat.postOnAnimation
 *
 * @param parent   协调布局parent
 * @param child    协调布局协调滑动的child
 * @param y        滑动目标位置y轴数值
 * @param duration 滑动执行时间
 * @return void
 */
public static void scrollTo(final CoordinatorLayout parent, final RecyclerView child, final int y, int duration) {
    final Scroller scroller = new Scroller(parent.getContext());
    scroller.startScroll(0, top, 0, y - top, duration);   //设置scroller的滚动偏移量
    ViewCompat.postOnAnimation(child, new Runnable() {
        @Override
        public void run() {
            //返回值为boolean，true说明滚动尚未完成，false说明滚动已经完成。
            // 这是一个很重要的方法，通常放在View.computeScroll()中，用来判断是否滚动是否结束。
            if (scroller.computeScrollOffset()) {
                int delta = scroller.getCurrY() - child.getTop();
                child.offsetTopAndBottom(delta);
                saveTop(child.getTop());
                parent.dispatchDependentViewsChanged(child);
                ViewCompat.postOnAnimation(child, this);
            }
        }
    });
}
 

/**
 * Attaches the {@link android.support.v7.widget.SnapHelper} to the provided RecyclerView, by calling
 * {@link RecyclerView#setOnFlingListener(RecyclerView.OnFlingListener)}.
 * You can call this method with {@code null} to detach it from the current RecyclerView.
 *
 * @param recyclerView The RecyclerView instance to which you want to add this helper or
 *                     {@code null} if you want to remove SnapHelper from the current
 *                     RecyclerView.
 * @throws IllegalArgumentException if there is already a {@link RecyclerView.OnFlingListener}
 *                                  attached to the provided {@link RecyclerView}.
 */
public void attachToRecyclerView(@Nullable RecyclerView recyclerView)
        throws IllegalStateException {
    if (mRecyclerView == recyclerView) {
        return; // nothing to do
    }
    if (mRecyclerView != null) {
        destroyCallbacks();
    }
    mRecyclerView = recyclerView;
    if (mRecyclerView != null) {
        setupCallbacks();
        mGravityScroller = new Scroller(mRecyclerView.getContext(),
                new DecelerateInterpolator());
        snapToTargetExistingView();
    }
}
 

public PageWidget(Context context) {
	super(context);

	// TODO Auto-generated constructor stub
	mPath0 = new Path();
	mPath1 = new Path();
	createDrawable();

	mPaint = new Paint();
	mPaint.setStyle(Paint.Style.FILL);

	ColorMatrix cm = new ColorMatrix();
	float array[] = { 0.55f, 0, 0, 0, 80.0f, 0, 0.55f, 0, 0, 80.0f, 0, 0,
			0.55f, 0, 80.0f, 0, 0, 0, 0.2f, 0 };
	cm.set(array);
	mColorMatrixFilter = new ColorMatrixColorFilter(cm);
	mMatrix = new Matrix();
	mScroller = new Scroller(getContext());

	mTouch.x = 0.01f;
	mTouch.y = 0.01f;
}
 

void initViewPager() {
    setWillNotDraw(false);
    setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
    setFocusable(true);
    final Context context = getContext();
    mScroller = new Scroller(context, sInterpolator);
    final ViewConfiguration configuration = ViewConfiguration.get(context);
    mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
    mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
    mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
    mLeftEdge = new EdgeEffectCompat(context);
    mRightEdge = new EdgeEffectCompat(context);

    final float density = context.getResources().getDisplayMetrics().density;
    mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
    mCloseEnough = (int) (CLOSE_ENOUGH * density);
    mDefaultGutterSize = (int) (DEFAULT_GUTTER_SIZE * density);

    ViewCompat.setAccessibilityDelegate(this, new MyAccessibilityDelegate());

    if (ViewCompat.getImportantForAccessibility(this)
            == ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
        ViewCompat.setImportantForAccessibility(this,
                ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
    }
}
 

/**
 * Attaches the {@link SnapHelper} to the provided RecyclerView, by calling
 * {@link RecyclerView#setOnFlingListener(RecyclerView.OnFlingListener)}.
 * You can call this method with {@code null} to detach it from the current RecyclerView.
 *
 * @param recyclerView The RecyclerView instance to which you want to add this helper or
 *                     {@code null} if you want to remove SnapHelper from the current
 *                     RecyclerView.
 *
 * @throws IllegalArgumentException if there is already a {@link RecyclerView.OnFlingListener}
 * attached to the provided {@link RecyclerView}.
 *
 */
public void attachToRecyclerView(@Nullable RecyclerView recyclerView)
        throws IllegalStateException {
    if (mRecyclerView == recyclerView) {
        return; // nothing to do
    }
    if (mRecyclerView != null) {
        destroyCallbacks();
    }
    mRecyclerView = recyclerView;
    if (mRecyclerView != null) {
        setupCallbacks();
        mGravityScroller = new Scroller(mRecyclerView.getContext(),
                new DecelerateInterpolator());
        snapToTargetExistingView();
    }
}
 

public BaseReadView(Context context, String bookId, List<BookMixAToc.mixToc.Chapters> chaptersList,
                    OnReadStateChangeListener listener) {
    super(context);
    this.listener = listener;
    this.bookId = bookId;

    mScreenWidth = ScreenUtils.getScreenWidth();
    mScreenHeight = ScreenUtils.getScreenHeight();

    mCurPageBitmap = Bitmap.createBitmap(mScreenWidth, mScreenHeight, Bitmap.Config.ARGB_8888);
    mNextPageBitmap = Bitmap.createBitmap(mScreenWidth, mScreenHeight, Bitmap.Config.ARGB_8888);
    mCurrentPageCanvas = new Canvas(mCurPageBitmap);
    mNextPageCanvas = new Canvas(mNextPageBitmap);

    mScroller = new Scroller(getContext());


    pagefactory = new PageFactory(getContext(), bookId, chaptersList);
    pagefactory.setOnReadStateChangeListener(listener);
}
 

void a()
{
    setWillNotDraw(false);
    setDescendantFocusability(0x40000);
    setFocusable(true);
    Context context = getContext();
    u = new Scroller(context, l);
    ViewConfiguration viewconfiguration = ViewConfiguration.get(context);
    float f1 = context.getResources().getDisplayMetrics().density;
    N = ViewConfigurationCompat.getScaledPagingTouchSlop(viewconfiguration);
    V = (int)(400F * f1);
    W = viewconfiguration.getScaledMaximumFlingVelocity();
    ae = new EdgeEffectCompat(context);
    af = new EdgeEffectCompat(context);
    Z = (int)(25F * f1);
    aa = (int)(2.0F * f1);
    L = (int)(16F * f1);
    ViewCompat.setAccessibilityDelegate(this, new aD(this));
    if (ViewCompat.getImportantForAccessibility(this) == 0)
    {
        ViewCompat.setImportantForAccessibility(this, 1);
    }
}
 

private void init() {
        scroller = new Scroller(getContext(), new DecelerateInterpolator());

        measureView(getHeaderView());
        headHeight = getHeaderView().getMeasuredHeight();
        getHeaderView().setPadding(0, -1 * headHeight, 0, 0);
        getHeaderView().invalidate();

//      this.setBackgroundResource(R.color.stand_default_bg_color);

        //添加头部视图
        super.addHeaderView(getHeaderView(), null, false);

        setOnScrollListener(this);

        super.setOnItemClickListener(this);
        super.setOnItemLongClickListener(this);
        super.setOnItemSelectedListener(this);
    }
 

private void init() {
    mJelloPaint = new Paint();
    mJelloPaint.setAntiAlias(true);
    mCheckedDrawable = getResources().getDrawable(R.drawable.checked);
    mOnCheckDrawable = getResources().getDrawable(R.drawable.check_on);
    mUnCheckedDrawable = getResources().getDrawable(R.drawable.uncheck);
    setJelloState();

    mJelloRect = new Rect();
    mScroller = new Scroller(getContext());
    mJelloPath = new Path();
    mInterpolator = new EaseOutElasticInterpolator();
    mDuration = DEFAULT_DURATION;


}
 

@Override
public void run() {

    final Scroller scroller = mScroller;
    boolean animationNotFinished = scroller.computeScrollOffset();
    final int x = scroller.getCurrX();
    int delta = x - mLastFlingX;

    trackMotion(delta);

    if (animationNotFinished) {
        mLastFlingX = x;
        post(this);
    } else {
        endFling();
    }

}
 

public CompatScroller(Context context) {
    if (VERSION.SDK_INT < VERSION_CODES.GINGERBREAD) {
        isPreGingerbread = true;
        scroller = new Scroller(context);

    } else {
        isPreGingerbread = false;
        overScroller = new OverScroller(context);
    }
}
 

private synchronized void initView() {
    mLeftViewIndex = -1;
    mRightViewIndex = 0;
    mDisplayOffset = 0;
    mCurrentX = 0;
    mNextX = 0;
    mMaxX = Integer.MAX_VALUE;
    mScroller = new Scroller(getContext());
    mGesture = new GestureDetector(getContext(), mOnGesture);
}
 

private void initView(Context context) {
	setOrientation(VERTICAL);
	mRefreshStatus = REFRESH_STATUS_NONE;
	mScroller = new Scroller(context);
	mScreenHeight = Resources.getSystem().getDisplayMetrics().heightPixels;
	mVelocityTracker = VelocityTracker.obtain();
	ViewConfiguration configuration = ViewConfiguration.get(context);
	mMinVelocity = configuration.getScaledMinimumFlingVelocity();
}
 

public CompatScroller(Context context) {
    if (VERSION.SDK_INT < VERSION_CODES.GINGERBREAD) {
        isPreGingerbread = true;
        scroller = new Scroller(context);

    } else {
        isPreGingerbread = false;
        overScroller = new OverScroller(context);
    }
}
 

public FanLayout(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

    initAttrs(context, attrs, defStyleAttr);

    mScrollAvailabilityRatio = .3F;
    final ViewConfiguration configuration = ViewConfiguration.get(context);
    mTouchSlop = configuration.getScaledTouchSlop();
    mScroller = new Scroller(getContext());
    mVelocityTracker = VelocityTracker.obtain();
}
 

public FilmstripScrollGesture(Context ctx, Handler handler, Listener listener,
                              TimeInterpolator interpolator)
{
    mHandler = handler;
    mListener = listener;
    mScroller = new Scroller(ctx);
    mXScrollAnimator = new ValueAnimator();
    mXScrollAnimator.addUpdateListener(mXScrollAnimatorUpdateListener);
    mXScrollAnimator.addListener(mXScrollAnimatorListener);
    mXScrollAnimator.setInterpolator(interpolator);
}
 

void initCustomViewAbove() {
	setWillNotDraw(false);
	setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
	setFocusable(true);
	final Context context = getContext();
	mScroller = new Scroller(context, sInterpolator);
	final ViewConfiguration configuration = ViewConfiguration.get(context);
	mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
	mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
	mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
	setInternalPageChangeListener(new SimpleOnPageChangeListener() {
		public void onPageSelected(int position) {
			if (mViewBehind != null) {
				switch (position) {
				case 0:
				case 2:
					mViewBehind.setChildrenEnabled(true);
					break;
				case 1:
					mViewBehind.setChildrenEnabled(false);
					break;
				}
			}
		}
	});

	final float density = context.getResources().getDisplayMetrics().density;
	mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
}
 

void initVerticalViewPager() {
    setWillNotDraw(false);
    setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
    setFocusable(true);
    final Context context = getContext();
    mScroller = new Scroller(context, sInterpolator);
    final ViewConfiguration configuration = ViewConfiguration.get(context);
    final float density = context.getResources().getDisplayMetrics().density;

    mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
    mMinimumVelocity = (int) (MIN_FLING_VELOCITY * density);
    mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
    mTopEdge = new EdgeEffectCompat(context);
    mBottomEdge = new EdgeEffectCompat(context);
    
    mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
    mCloseEnough = (int) (CLOSE_ENOUGH * density);
    mDefaultGutterSize = (int) (DEFAULT_GUTTER_SIZE * density);

    ViewCompat.setAccessibilityDelegate(this, new MyAccessibilityDelegate());

    if (ViewCompat.getImportantForAccessibility(this)
            == ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
        ViewCompat.setImportantForAccessibility(this,
                ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
    }
}
 

public CompatScroller(Context context) {
    if (VERSION.SDK_INT < VERSION_CODES.GINGERBREAD) {
        isPreGingerbread = true;
        scroller = new Scroller(context);

    } else {
        isPreGingerbread = false;
        overScroller = new OverScroller(context);
    }
}
 

void initViewPager() {
    setWillNotDraw(false);
    setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
    setFocusable(true);
    final Context context = getContext();
    mScroller = new Scroller(context, sInterpolator);
    final ViewConfiguration configuration = ViewConfiguration.get(context);
    final float density = context.getResources().getDisplayMetrics().density;

    mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
    mMinimumVelocity = (int) (MIN_FLING_VELOCITY * density);
    mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
    mLeftEdge = new EdgeEffectCompat(context);
    mRightEdge = new EdgeEffectCompat(context);

    mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
    mCloseEnough = (int) (CLOSE_ENOUGH * density);
    mDefaultGutterSize = (int) (DEFAULT_GUTTER_SIZE * density);

    ViewCompat.setAccessibilityDelegate(this, new MyAccessibilityDelegate());

    if (ViewCompat.getImportantForAccessibility(this)
            == ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
        ViewCompat.setImportantForAccessibility(this,
                ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
    }
}
 

public FlingViewGroup(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.setLayoutParams(new ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.MATCH_PARENT));

    mScroller = new Scroller(context);
    ViewConfiguration config = ViewConfiguration.get(getContext());
    mTouchSlop = config.getScaledTouchSlop();
    mMaximumVelocity = config.getScaledMaximumFlingVelocity();
}
 

/**
 * Constructor
 * @param context the current context
 * @param listener the scrolling listener
 */
public WheelScroller(Context context, ScrollingListener listener) {
    gestureDetector = new GestureDetector(context, gestureListener);
    gestureDetector.setIsLongpressEnabled(false);
    
    scroller = new Scroller(context);

    this.listener = listener;
    this.context = context;
}
 

public CompatScroller(Context context) {
	if (VERSION.SDK_INT < VERSION_CODES.GINGERBREAD) {
		isPreGingerbread = true;
		scroller = new Scroller(context);

	} else {
		isPreGingerbread = false;
		overScroller = new OverScroller(context);
	}
}
 

public CompatScroller(Context context) {
	if (VERSION.SDK_INT < VERSION_CODES.GINGERBREAD) {
		isPreGingerbread = true;
		scroller = new Scroller(context);
		
	} else {
		isPreGingerbread = false;
		overScroller = new OverScroller(context);
	}
}
 

public MyScrollView(Context context, AttributeSet attrs, int defStyle) {

		super(context, attrs, defStyle);
		mWallpaperManager = WallpaperManager.getInstance(context);
		mScroller = new Scroller(context);
		mCurScreen = mDefaultScreen;
		mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
	}
 

private void init(Context context) {
    WindowManager wm = (WindowManager) context.getSystemService(
            Context.WINDOW_SERVICE);
    DisplayMetrics dm = new DisplayMetrics();
    wm.getDefaultDisplay().getMetrics(dm);
    mScreenHeight = dm.heightPixels;
    mScroller = new Scroller(context);
}