CoordinatorLayout忽略具有锚点的视图的边距

鉴于我正在使用这样的布局:

         

这几乎是标准的Cheesesquare样本 – 除了FloatingActionButton,我想提升大约20dp。

但是,这不起作用。 无论我使用边距,填充等 – 按钮将始终位于锚点边缘的中心,如下所示:

FAB将忽略保证金

如何按预期将FAB向上移动20dp?

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尝试将其放在具有填充的线性布局中:

    

因为在关于CoordinatorLayout和margins的design-support-lib中可能存在bug ,我编写了一个FrameLayout ,它实现/复制与FAB相同的“Behavior”,并允许设置padding来模拟效果:

一定要把它放在android.support.design.widget包中,因为它需要访问一些包作用域的类。

 /* * Copyright (C) 2015 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import android.annotation.TargetApi; import android.content.Context; import android.graphics.Rect; import android.os.Build; import android.support.v4.view.ViewCompat; import android.support.v4.view.ViewPropertyAnimatorListener; import android.util.AttributeSet; import android.view.View; import android.view.animation.Animation; import android.widget.FrameLayout; import com.company.android.R; import java.util.List; @CoordinatorLayout.DefaultBehavior(FrameLayoutWithBehavior.Behavior.class) public class FrameLayoutWithBehavior extends FrameLayout { public FrameLayoutWithBehavior(final Context context) { super(context); } public FrameLayoutWithBehavior(final Context context, final AttributeSet attrs) { super(context, attrs); } public FrameLayoutWithBehavior(final Context context, final AttributeSet attrs, final int defStyleAttr) { super(context, attrs, defStyleAttr); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public FrameLayoutWithBehavior(final Context context, final AttributeSet attrs, final int defStyleAttr, final int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); } public static class Behavior extends android.support.design.widget.CoordinatorLayout.Behavior { private static final boolean SNACKBAR_BEHAVIOR_ENABLED; private Rect mTmpRect; private boolean mIsAnimatingOut; private float mTranslationY; public Behavior() { } @Override public boolean layoutDependsOn(CoordinatorLayout parent, FrameLayoutWithBehavior child, View dependency) { return SNACKBAR_BEHAVIOR_ENABLED && dependency instanceof Snackbar.SnackbarLayout; } @Override public boolean onDependentViewChanged(CoordinatorLayout parent, FrameLayoutWithBehavior child, View dependency) { if (dependency instanceof Snackbar.SnackbarLayout) { this.updateFabTranslationForSnackbar(parent, child, dependency); } else if (dependency instanceof AppBarLayout) { AppBarLayout appBarLayout = (AppBarLayout) dependency; if (this.mTmpRect == null) { this.mTmpRect = new Rect(); } Rect rect = this.mTmpRect; ViewGroupUtils.getDescendantRect(parent, dependency, rect); if (rect.bottom < = appBarLayout.getMinimumHeightForVisibleOverlappingContent()) { if (!this.mIsAnimatingOut && child.getVisibility() == VISIBLE) { this.animateOut(child); } } else if (child.getVisibility() != VISIBLE) { this.animateIn(child); } } return false; } private void updateFabTranslationForSnackbar(CoordinatorLayout parent, FrameLayoutWithBehavior fab, View snackbar) { float translationY = this.getFabTranslationYForSnackbar(parent, fab); if (translationY != this.mTranslationY) { ViewCompat.animate(fab) .cancel(); if (Math.abs(translationY - this.mTranslationY) == (float) snackbar.getHeight()) { ViewCompat.animate(fab) .translationY(translationY) .setInterpolator(AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR) .setListener((ViewPropertyAnimatorListener) null); } else { ViewCompat.setTranslationY(fab, translationY); } this.mTranslationY = translationY; } } private float getFabTranslationYForSnackbar(CoordinatorLayout parent, FrameLayoutWithBehavior fab) { float minOffset = 0.0F; List dependencies = parent.getDependencies(fab); int i = 0; for (int z = dependencies.size(); i < z; ++i) { View view = (View) dependencies.get(i); if (view instanceof Snackbar.SnackbarLayout && parent.doViewsOverlap(fab, view)) { minOffset = Math.min(minOffset, ViewCompat.getTranslationY(view) - (float) view.getHeight()); } } return minOffset; } private void animateIn(FrameLayoutWithBehavior button) { button.setVisibility(View.VISIBLE); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { ViewCompat.animate(button) .scaleX(1.0F) .scaleY(1.0F) .alpha(1.0F) .setInterpolator(AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR) .withLayer() .setListener((ViewPropertyAnimatorListener) null) .start(); } else { Animation anim = android.view.animation.AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_in); anim.setDuration(200L); anim.setInterpolator(AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR); button.startAnimation(anim); } } private void animateOut(final FrameLayoutWithBehavior button) { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { ViewCompat.animate(button) .scaleX(0.0F) .scaleY(0.0F) .alpha(0.0F) .setInterpolator(AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR) .withLayer() .setListener(new ViewPropertyAnimatorListener() { public void onAnimationStart(View view) { Behavior.this.mIsAnimatingOut = true; } public void onAnimationCancel(View view) { Behavior.this.mIsAnimatingOut = false; } public void onAnimationEnd(View view) { Behavior.this.mIsAnimatingOut = false; view.setVisibility(View.GONE); } }) .start(); } else { Animation anim = android.view.animation.AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_out); anim.setInterpolator(AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR); anim.setDuration(200L); anim.setAnimationListener(new AnimationUtils.AnimationListenerAdapter() { public void onAnimationStart(Animation animation) { Behavior.this.mIsAnimatingOut = true; } public void onAnimationEnd(Animation animation) { Behavior.this.mIsAnimatingOut = false; button.setVisibility(View.GONE); } }); button.startAnimation(anim); } } static { SNACKBAR_BEHAVIOR_ENABLED = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB; } } } 

要将FloatingActionButton锚定在AppBar下面,如下所示: Fab作为AppBar的主播

扩展FloatingActionButton并覆盖offsetTopAndBottom

 public class OffsetFloatingActionButton extends FloatingActionButton { public OffsetFloatingActionButton(Context context) { this(context, null); } public OffsetFloatingActionButton(Context context, AttributeSet attrs) { this(context, attrs, 0); } public OffsetFloatingActionButton(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); ViewCompat.offsetTopAndBottom(this, 0); } @Override public void offsetTopAndBottom(int offset) { super.offsetTopAndBottom((int) (offset + (getHeight() * 0.5f))); } } 

简单的解决方法是将随机布局锚定到FAB锚定的位置,给它特定的边距,然后将FAB锚定到随机布局,就像这样