从片段中调用startActionMode

Question

我想在单击按钮时从片段启动连续动作模式菜单。我不确定如何从片段中的onClick方法调用“ startActionMode（）”。

MyFragment

class MyFragment : Fragment() {
    ...
    
    private var mActionMode: ActionMode? = null 
    
    // when this button is clicked it should launch the Contextual Action Bar (CAB) 
    fun myCAB() {
        // Check to see CAB is currenty active. 
        if(mActionMode != null) return        
        mActionMode = mActivity.startActionMode(actionModeCallback)
    }

    // ActionMode.Callback interface, handles actions for contextual CAB
    private val actionModeCallback: ActionMode.Callback = object : ActionMode.Callback {
         ... 
    }
}

我尝试使用

• requireActivity，
• 从onAttach（活动：活动）中引用活动，

两个选项均返回类型未命中匹配项。 必填：androidx.appcompt.view.ActtionMode？ 找到：android.view.ActionMode？

Answer 1

您可以投射Activity，然后调用startSupportAction模式。

mActionMode = (activity as MainActivity?)!!.startSupportActionMode(actionModeCallback)

这就是代码中的样子。

class MyFragment : Fragment() {
    ...

    private var mAction: ActionMode? = null

    fun myCAB() {
        if(mActionMode!= null) return
      
        // as casts the type if is successful or returns null
        mAction = (activity as MainActiivty?)!!.startSupportActionMode(actionModeCallback)
    } 

    private val actionModeCallback: ActionMode.Callback = object : ActionModeCallback {
        ... 
    }
}