86 lines
3.8 KiB
Java
86 lines
3.8 KiB
Java
package com.example.nanchen.aiyaschoolpush.behavior;
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import android.content.Context;
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import android.support.design.widget.CoordinatorLayout;
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import android.support.design.widget.FloatingActionButton;
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import android.support.v4.view.ViewCompat;
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import android.support.v4.view.ViewPropertyAnimatorListener;
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import android.support.v4.view.animation.FastOutSlowInInterpolator;
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import android.util.AttributeSet;
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import android.view.View;
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import android.view.ViewGroup;
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import android.view.animation.Interpolator;
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/**
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* Author: nanchen
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* Email: liushilin520@foxmail.com
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* Date: 2017-04-28 11:41
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*/
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public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
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private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
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private boolean mIsAnimatingOut = false;
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public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
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super();
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}
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@Override
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public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
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final View directTargetChild, final View target, final int nestedScrollAxes) {
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// Ensure we react to vertical scrolling
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return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL
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|| super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
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}
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@Override
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public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
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final View target, final int dxConsumed, final int dyConsumed,
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final int dxUnconsumed, final int dyUnconsumed) {
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super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
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if (dyConsumed > 0 && !this.mIsAnimatingOut && child.getVisibility() == View.VISIBLE) {
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// User scrolled down and the FAB is currently visible -> hide the FAB
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animateOut(child);
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} else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
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// User scrolled up and the FAB is currently not visible -> show the FAB
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animateIn(child);
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}
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}
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// Same animation that FloatingActionButton.Behavior uses to hide the FAB when the AppBarLayout exits
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private void animateOut(final FloatingActionButton button) {
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ViewCompat.animate(button).translationY(button.getHeight() + getMarginBottom(button)).setInterpolator(INTERPOLATOR).withLayer()
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.setListener(new ViewPropertyAnimatorListener() {
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public void onAnimationStart(View view) {
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ScrollAwareFABBehavior.this.mIsAnimatingOut = true;
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}
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public void onAnimationCancel(View view) {
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ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
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}
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public void onAnimationEnd(View view) {
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ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
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view.setVisibility(View.GONE);
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}
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}).start();
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}
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// Same animation that FloatingActionButton.Behavior uses to show the FAB when the AppBarLayout enters
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private void animateIn(FloatingActionButton button) {
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button.setVisibility(View.VISIBLE);
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ViewCompat.animate(button).translationY(0)
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.setInterpolator(INTERPOLATOR).withLayer().setListener(null)
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.start();
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}
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private int getMarginBottom(View v) {
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int marginBottom = 0;
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final ViewGroup.LayoutParams layoutParams = v.getLayoutParams();
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if (layoutParams instanceof ViewGroup.MarginLayoutParams) {
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marginBottom = ((ViewGroup.MarginLayoutParams) layoutParams).bottomMargin;
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}
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return marginBottom;
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}
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}
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