非持有snackbar实例的情况下关闭永久显示的snackbar

简书链接:非持有snackbar实例的情况下关闭永久显示的snackbar
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根据布局分析发现是添加到了根节点，也就是我传递的coordinatelayout最后一个子view.

布局源码为

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ 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.
-->

<view
  xmlns:android="http://schemas.android.com/apk/res/android"
  class="com.google.android.material.snackbar.SnackbarContentLayout"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_gravity="bottom">

  <TextView
    android:id="@+id/snackbar_text"
    style="?attr/snackbarTextViewStyle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:layout_gravity="center_vertical|left|start"/>

  <Button
    android:id="@+id/snackbar_action"
    style="?attr/snackbarButtonStyle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_vertical|right|end"
    android:minWidth="48dp"
    android:visibility="gone"/>

</view>

文件为mtrl_layout_snackbar_include.xml
因此得到如下解决办法 ,

   public static void closeSnackBar(ViewGroup root) {
//        class="com.google.android.material.snackbar.SnackbarContentLayout"
        View snackBarButton = root.findViewById(R.id.snackbar_action);
        if(snackBarButton!=null){
            snackBarButton.callOnClick();
        }
    }

也可以尝试获取构建snackbar的root 布局最后一个view判断是否等于SnackbarContentLayout
另外我尝试分析com.google.android.material.snackbar.SnackbarManager实例发现是默认类，没权限访问而且也没有相关的关闭方法

如果没有actionview呢

进一步分析，com.google.android.material.snackbar.Snackbar$SnackbarLayout{c79a47b VFE…… …….. 22,2106-1058,2238}

下面是

com.google.android.material.snackbar.SnackbarContentLayout{2e6a9aa V.E…… …….. 22,0-1014,132}

SnackBarLayout源码

*/
  @RestrictTo(LIBRARY_GROUP)
  public static final class SnackbarLayout extends BaseTransientBottomBar.SnackbarBaseLayout {
    public SnackbarLayout(Context context) {
      super(context);
    }

    public SnackbarLayout(Context context, AttributeSet attrs) {
      super(context, attrs);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
      super.onMeasure(widthMeasureSpec, heightMeasureSpec);
      // Work around our backwards-compatible refactoring of Snackbar and inner content
      // being inflated against snackbar's parent (instead of against the snackbar itself).
      // Every child that is width=MATCH_PARENT is remeasured again and given the full width
      // minus the paddings.
      int childCount = getChildCount();
      int availableWidth = getMeasuredWidth() - getPaddingLeft() - getPaddingRight();
      for (int i = 0; i < childCount; i++) {
        View child = getChildAt(i);
        if (child.getLayoutParams().width == ViewGroup.LayoutParams.MATCH_PARENT) {
          child.measure(
              MeasureSpec.makeMeasureSpec(availableWidth, MeasureSpec.EXACTLY),
              MeasureSpec.makeMeasureSpec(child.getMeasuredHeight(), MeasureSpec.EXACTLY));
        }
      }
    }
  }

  private TextView getMessageView() {
    return getContentLayout().getMessageView();
  }

  private Button getActionView() {
    return getContentLayout().getActionView();
  }

  private SnackbarContentLayout getContentLayout() {
    return (SnackbarContentLayout) view.getChildAt(0);
  }
}

最后的调整

/*
要关闭源码首先需要SnackbarManager 虽然是静态，但是不是公开的，需要反射
 private static SnackbarManager snackbarManager;

  static SnackbarManager getInstance() {
    if (snackbarManager == null) {
      snackbarManager = new SnackbarManager();
    }
    return snackbarManager;
  }

  @NonNull private final Object lock;
  @NonNull private final Handler handler;

  @Nullable private SnackbarRecord currentSnackbar;
  @Nullable private SnackbarRecord nextSnackbar;

  拿到 snackbarrecord,

  在snackabar的父类 BaseTransientBottomBar
   void onViewHidden(int event) {
    // First tell the SnackbarManager that it has been dismissed
    SnackbarManager.getInstance().onDismissed(managerCallback);
    if (callbacks != null) {
      // Notify the callbacks. Do that from the end of the list so that if a callback
      // removes itself as the result of being called, it won't mess up with our iteration
      int callbackCount = callbacks.size();
      for (int i = callbackCount - 1; i >= 0; i--) {
        callbacks.get(i).onDismissed((B) this, event);
      }
    }
    // Lastly, hide and remove the view from the parent (if attached)
    ViewParent parent = view.getParent();
    if (parent instanceof ViewGroup) {
      ((ViewGroup) parent).removeView(view);
    }
  }
  方法中，参数为3， ，可移除handler.


 */
    public static void closeSnackBar(ViewGroup root) {
//        class="com.google.android.material.snackbar.SnackbarContentLayout"
//        root= (ViewGroup) root.getChildAt(root.getChildCount()-1);//可以优化效率，可我总觉得这样不太靠谱
      View snackBarButton = root.findViewById(R.id.snackbar_action);//action只适用于错误。
        if(snackBarButton!=null){
            if(snackBarButton.getVisibility()==View.VISIBLE){//如果是没有设置action按钮的，则此方法无效。
                snackBarButton.callOnClick();
            }else{//方法有一点点瑕疵，因为倒计时的handler并没有取消，如果要解决这个问题，需要反射SnackbarManager 拿到record进行操作，有兴趣并且成功的朋友可以留言交流。
                Snackbar.SnackbarLayout snackbarLayout= (Snackbar.SnackbarLayout) snackBarButton.getParent().getParent();
                ViewGroup parent = (ViewGroup) snackbarLayout.getParent();
                if(parent!=null){
                    parent.removeView(snackbarLayout);
                }
            }

        }
    }
}