kunfei
5 years ago
parent
7f0a484693
commit
948e87a3e7
@ -1,20 +0,0 @@ |
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package io.legado.app.ui.book.read.page.delegate |
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import android.view.MotionEvent |
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fun MotionEvent.toAction(action: Int): MotionEvent { |
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return MotionEvent.obtain( |
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downTime, |
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eventTime, |
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action, |
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x, |
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y, |
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pressure, |
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size, |
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metaState, |
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xPrecision, |
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yPrecision, |
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deviceId, |
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edgeFlags |
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) |
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} |
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@ -0,0 +1,231 @@ |
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package io.legado.app.ui.widget.text |
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import android.annotation.SuppressLint |
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import android.content.Context |
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import android.util.AttributeSet |
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import android.view.MotionEvent |
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import android.view.VelocityTracker |
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import android.view.ViewConfiguration |
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import android.view.animation.Interpolator |
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import android.widget.OverScroller |
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import androidx.appcompat.widget.AppCompatTextView |
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import androidx.core.view.ViewCompat |
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import kotlin.math.abs |
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import kotlin.math.max |
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import kotlin.math.min |
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open class InertiaScrollTextView : AppCompatTextView { |
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constructor(context: Context) : super(context) |
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constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) |
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constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) |
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: super(context, attrs, defStyleAttr) |
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private val scrollStateIdle = 0 |
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private val scrollStateDragging = 1 |
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val scrollStateSettling = 2 |
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private val mViewFling: ViewFling by lazy { ViewFling() } |
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private var velocityTracker: VelocityTracker? = null |
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private var mScrollState = scrollStateIdle |
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private var mLastTouchY: Int = 0 |
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private var mTouchSlop: Int = 0 |
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private var mMinFlingVelocity: Int = 0 |
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private var mMaxFlingVelocity: Int = 0 |
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//滑动距离的最大边界 |
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private var mOffsetHeight: Int = 0 |
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//f(x) = (x-1)^5 + 1 |
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private val sQuinticInterpolator = Interpolator { |
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var t = it |
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t -= 1.0f |
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t * t * t * t * t + 1.0f |
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} |
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init { |
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val vc = ViewConfiguration.get(context) |
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mTouchSlop = vc.scaledTouchSlop |
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mMinFlingVelocity = vc.scaledMinimumFlingVelocity |
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mMaxFlingVelocity = vc.scaledMaximumFlingVelocity |
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} |
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fun atTop(): Boolean { |
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return scrollY <= 0 |
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} |
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fun atBottom(): Boolean { |
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return scrollY >= mOffsetHeight |
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} |
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override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { |
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super.onMeasure(widthMeasureSpec, heightMeasureSpec) |
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initOffsetHeight() |
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} |
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override fun onTextChanged( |
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text: CharSequence?, |
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start: Int, |
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lengthBefore: Int, |
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lengthAfter: Int |
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) { |
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super.onTextChanged(text, start, lengthBefore, lengthAfter) |
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initOffsetHeight() |
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} |
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private fun initOffsetHeight() { |
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val mLayoutHeight: Int |
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//获得内容面板 |
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val mLayout = layout ?: return |
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//获得内容面板的高度 |
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mLayoutHeight = mLayout.height |
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//计算滑动距离的边界 |
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mOffsetHeight = mLayoutHeight + totalPaddingTop + totalPaddingBottom - measuredHeight |
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} |
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override fun scrollTo(x: Int, y: Int) { |
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super.scrollTo(x, min(y, mOffsetHeight)) |
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} |
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@SuppressLint("ClickableViewAccessibility") |
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override fun onTouchEvent(event: MotionEvent?): Boolean { |
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event?.let { |
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if (velocityTracker == null) { |
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velocityTracker = VelocityTracker.obtain() |
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} |
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velocityTracker?.addMovement(it) |
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when (event.action) { |
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MotionEvent.ACTION_DOWN -> { |
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setScrollState(scrollStateIdle) |
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mLastTouchY = (event.y + 0.5f).toInt() |
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} |
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MotionEvent.ACTION_MOVE -> { |
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val y = (event.y + 0.5f).toInt() |
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var dy = mLastTouchY - y |
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if (mScrollState != scrollStateDragging) { |
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var startScroll = false |
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if (abs(dy) > mTouchSlop) { |
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if (dy > 0) { |
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dy -= mTouchSlop |
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} else { |
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dy += mTouchSlop |
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} |
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startScroll = true |
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} |
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if (startScroll) { |
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setScrollState(scrollStateDragging) |
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} |
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} |
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if (mScrollState == scrollStateDragging) { |
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mLastTouchY = y |
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} |
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} |
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MotionEvent.ACTION_UP -> { |
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velocityTracker?.computeCurrentVelocity(1000, mMaxFlingVelocity.toFloat()) |
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val yVelocity = velocityTracker?.yVelocity ?: 0f |
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if (abs(yVelocity) > mMinFlingVelocity) { |
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mViewFling.fling(-yVelocity.toInt()) |
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} else { |
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setScrollState(scrollStateIdle) |
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} |
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resetTouch() |
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} |
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MotionEvent.ACTION_CANCEL -> { |
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resetTouch() |
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} |
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} |
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} |
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return super.onTouchEvent(event) |
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} |
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private fun resetTouch() { |
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velocityTracker?.clear() |
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} |
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private fun setScrollState(state: Int) { |
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if (state == mScrollState) { |
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return |
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} |
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mScrollState = state |
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if (state != scrollStateSettling) { |
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mViewFling.stop() |
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} |
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} |
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/** |
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* 惯性滚动 |
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*/ |
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private inner class ViewFling : Runnable { |
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private var mLastFlingY = 0 |
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private val mScroller: OverScroller = OverScroller(context, sQuinticInterpolator) |
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private var mEatRunOnAnimationRequest = false |
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private var mReSchedulePostAnimationCallback = false |
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override fun run() { |
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disableRunOnAnimationRequests() |
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val scroller = mScroller |
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if (scroller.computeScrollOffset()) { |
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val y = scroller.currY |
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val dy = y - mLastFlingY |
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mLastFlingY = y |
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if (dy < 0 && scrollY > 0) { |
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scrollBy(0, max(dy, -scrollY)) |
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} else if (dy > 0 && scrollY < mOffsetHeight) { |
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scrollBy(0, min(dy, mOffsetHeight - scrollY)) |
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} |
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postOnAnimation() |
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} |
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enableRunOnAnimationRequests() |
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} |
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fun fling(velocityY: Int) { |
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mLastFlingY = 0 |
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setScrollState(scrollStateSettling) |
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mScroller.fling( |
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0, |
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0, |
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0, |
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velocityY, |
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Integer.MIN_VALUE, |
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Integer.MAX_VALUE, |
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Integer.MIN_VALUE, |
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Integer.MAX_VALUE |
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) |
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postOnAnimation() |
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} |
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fun stop() { |
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removeCallbacks(this) |
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mScroller.abortAnimation() |
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} |
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private fun disableRunOnAnimationRequests() { |
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mReSchedulePostAnimationCallback = false |
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mEatRunOnAnimationRequest = true |
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} |
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private fun enableRunOnAnimationRequests() { |
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mEatRunOnAnimationRequest = false |
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if (mReSchedulePostAnimationCallback) { |
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postOnAnimation() |
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} |
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} |
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internal fun postOnAnimation() { |
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if (mEatRunOnAnimationRequest) { |
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mReSchedulePostAnimationCallback = true |
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} else { |
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removeCallbacks(this) |
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ViewCompat.postOnAnimation(this@InertiaScrollTextView, this) |
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} |
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} |
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} |
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} |
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