紫塞明珠跳蚤市场,柳濑早纪番号,重庆百姓满意度
前言
promoted actions是指一种操作按钮，它不是放在actionbar中，而是直接在可见的ui布局中（当然这里的ui指的是setcontentview所管辖的范围）。因此它更容易在代码中被获取到（试想如果你要在actionbar中获取一个菜单按钮是不是很难？），promoted actions往往主要用于一个界面的主要操作，比如在email的邮件列表界面，promoted action可以用于接受一个新邮件。promoted action在外观上其实就是一个悬浮按钮，更常见的是漂浮在界面上的圆形按钮，一般我直接将promoted action称作悬浮按钮，英文名称float action button 简称（fab，不是fbi哈）。
系统自带的 fab 也会随着页面上下滚动,但是淡出或者进入的效果太不自然。
这里记录一个小知识点,fab 随着页面的 recyclerview 上下滚动而渐变的动画效果。
包含 fab 控件的布局如下:
<?xml version="1.0" encoding="utf-8"?> <android.support.design.widget.coordinatorlayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".view.activity.mainactivity"> <android.support.design.widget.appbarlayout android:layout_width="match_parent" android:layout_height="wrap_content" android:theme="@style/apptheme.appbaroverlay"> <android.support.v7.widget.toolbar android:id="@+id/toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionbarsize" android:background="?attr/colorprimary" app:layout_scrollflags="scroll|enteralways" app:popuptheme="@style/apptheme.popupoverlay" /> <android.support.design.widget.tablayout android:id="@+id/tab_layout" app:tabindicatorcolor="#ffffff" android:layout_width="match_parent" android:layout_height="wrap_content"> </android.support.design.widget.tablayout> </android.support.design.widget.appbarlayout> <include layout="@layout/content_main" /> <android.support.design.widget.floatingactionbutton android:id="@+id/fab" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="@dimen/fab_margin" android:src="@android:drawable/ic_dialog_email" app:layout_behavior="com.wu.allen.zhuanlan.util.scrollawarefabbehavior"/> </android.support.design.widget.coordinatorlayout>
实现的 java 代码如下:
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public class scrollawarefabbehavior extends floatingactionbutton.behavior {
private static final interpolator interpolator = new fastoutslowininterpolator();
private boolean misanimatingout = false;
public scrollawarefabbehavior(context context, attributeset attrs) {
super();
}
@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);
}
@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);
}
}
// 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);
}
}
}
fab_in.xml 文件如下(fab_out.xml 同理),当然要改变淡出或者进入的样式,一般修改这里的 xml 文件就可以了 :
<?xml version="1.0" encoding="utf-8"?> <set xmlns:android="http://schemas.android.com/apk/res/android"> <alpha android:fromalpha="0.0" android:toalpha="1.0"/> <scale android:fromxscale="0.0" android:fromyscale="0.0" android:toxscale="1.0" android:toyscale="1.0" android:pivotx="50%" android:pivoty="50%"/> </set>
<?xml version="1.0" encoding="utf-8"?> <set xmlns:android="http://schemas.android.com/apk/res/android"> <alpha android:fromalpha="1.0" android:toalpha="0.0"/> <scale android:fromxscale="1.0" android:fromyscale="1.0" android:toxscale="0.0" android:toyscale="0.0" android:pivotx="50%" android:pivoty="50%"/> </set>
大致效果就像上面。
总结
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