css - 设置按钮在悬停时出现

Question

我在 angular 4 material 表格单元格中有一个按钮，我只想在将鼠标悬停在表格行上时出现:

<md-cell *cdkCellDef="let row" contenteditable='false' > 
        <div *ngIf="!row.editorEnabled" >{{row.goalStatusName}}
            <button md-icon-button><md-icon (click)="row.editorEnabled=true;" mdTooltip="Edit">mode_edit</md-icon></button>
          </div>
</md-cell>

我如何实现这一目标？

更新:完整代码:

<md-cell *cdkCellDef="let row" contenteditable='false' > 
        <div *ngIf="!row.editorEnabled" >{{row.goalStatusName}}
            <button md-icon-button><md-icon (click)="row.editorEnabled=true;" class="editButton" mdTooltip="Edit">mode_edit</md-icon></button>
          </div>
        <div *ngIf="row.editorEnabled" >
          <md-input-container><input mdInput [(ngModel)]="row.goalStatusName" #goalName></md-input-container>
            <button md-icon-button>
              <md-icon (click)="modifyGoal(row.goalStatusId,row.goalStatusName)" mdTooltip="Save" style="color:green;font:bold;" >done</md-icon>
            </button>
            <button md-icon-button>
              <md-icon (click)="row.editorEnabled=false" mdTooltip="Cancel" style="color:red;font:bold;" >clear</md-icon>
            </button>
          </div>
    </md-cell>

Answer 1

button{ display:none}
md-cell:hover{

  button{
     display:block
  }
}