import android.content.Context;
import android.os.Build;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPropertyAnimatorListener;
import android.support.v4.view.animation.FastOutSlowInInterpolator;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.animation.Interpolator;
/**
* Created by Bruce Too
* On 6/2/15.
* At 09:14
* 只需要在 layout 中
* app:layout_behavior="com.support.android.designlibdemo.ScrollAwareFABBehavior" 使用就OK
*/
public class ScrollAwareFABBehavior
extends FloatingActionButton.Behavior {
private static final Interpolator INTERPOLATOR =
new FastOutSlowInInterpolator();
private boolean mIsAnimatingOut =
false;
public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
super();
}
/**
* 滚动开始的监听
* @param coordinatorLayout
* @param child 设置了Behavior得子view
* @param directTargetChild
* @param target 需要滚动的子view
* @param nestedScrollAxes 滚动轴方向 SCROLL_AXIS_HORIZONTAL, SCROLL_AXIS_VERTICAL
* @return
*/
@Override
public boolean onStartNestedScroll(
final CoordinatorLayout coordinatorLayout,
final FloatingActionButton child,
final View directTargetChild,
final View target,
final int nestedScrollAxes) {
// Ensure we react to vertical scrolling
return nestedScrollAxes ==
ViewCompat.SCROLL_AXIS_VERTICAL
||
super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
}
/**
* 滚动时的监听
* 每一个设置了Behavior 并且是 CoordinatorLayout的直接子view都会调用此方法
* 比如 FloatActionButton,AppBarLayout
* @param coordinatorLayout the CoordinatorLayout parent of the view this Behavior is associated with
* @param child the child view of the CoordinatorLayout this Behavior is associated with
* @param target the descendant view of the CoordinatorLayout performing the nested scroll
* @param dxConsumed horizontal pixels consumed by the target's own scrolling operation
* @param dyConsumed vertical pixels consumed by the target's own scrolling operation
* @param dxUnconsumed horizontal pixels not consumed by the target's own scrolling operation, but requested by the user
*/
@Override
public void onNestedScroll(
final CoordinatorLayout coordinatorLayout,
final FloatingActionButton child,
final View target,
final int dxConsumed,
final int dyConsumed,
final int dxUnconsumed,
final int dyUnconsumed) {
super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
if (dyConsumed > 0 && !
this.mIsAnimatingOut && child.getVisibility() ==
View.VISIBLE) {
// User scrolled down and the FAB is currently visible -> hide the FAB
animateOut(child);
} else if (dyConsumed < 0 && child.getVisibility() !=
View.VISIBLE) {
// User scrolled up and the FAB is currently not visible -> show the FAB
animateIn(child);
}
/**
* 如果>=V22.2.1'
* 可以使用系统预设的动画
*/
// if (dyConsumed > 0 && child.getVisibility() == View.VISIBLE) {
// // User scrolled down and the FAB is currently visible -> hide the FAB
// child.hide();
// } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
// // User scrolled up and the FAB is currently not visible -> show the FAB
// child.show();
// }
}
// Same animation that FloatingActionButton.Behavior uses to hide the FAB when the AppBarLayout exits
private void animateOut(
final FloatingActionButton button) {
if (Build.VERSION.SDK_INT >= 14
) {
ViewCompat.animate(button).scaleX(0.0F).scaleY(0.0F).alpha(0.0F
).setInterpolator(INTERPOLATOR).withLayer()
.setListener(new ViewPropertyAnimatorListener() {
public void onAnimationStart(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut =
true;
}
public void onAnimationCancel(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut =
false;
}
public void onAnimationEnd(View view) {
ScrollAwareFABBehavior.this.mIsAnimatingOut =
false;
view.setVisibility(View.GONE);
}
}).start();
} else {
Animation anim =
AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_out);
anim.setInterpolator(INTERPOLATOR);
anim.setDuration(200L
);
anim.setAnimationListener(new Animation.AnimationListener() {
public void onAnimationStart(Animation animation) {
ScrollAwareFABBehavior.this.mIsAnimatingOut =
true;
}
public void onAnimationEnd(Animation animation) {
ScrollAwareFABBehavior.this.mIsAnimatingOut =
false;
button.setVisibility(View.GONE);
}
@Override
public void onAnimationRepeat(
final Animation animation) {
}
});
button.startAnimation(anim);
}
}
// Same animation that FloatingActionButton.Behavior uses to show the FAB when the AppBarLayout enters
private void animateIn(FloatingActionButton button) {
button.setVisibility(View.VISIBLE);
if (Build.VERSION.SDK_INT >= 14
) {
ViewCompat.animate(button).scaleX(1.0F).scaleY(1.0F).alpha(1.0F
)
.setInterpolator(INTERPOLATOR).withLayer().setListener(null)
.start();
} else {
Animation anim =
AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_in);
anim.setDuration(200L
);
anim.setInterpolator(INTERPOLATOR);
button.startAnimation(anim);
}
}
}
转载于:https://www.cnblogs.com/jasonkent27/p/5347591.html
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