从 MainActivity 中删除视图

Question

我有一个回收站视图应用程序，它从用户那里获取数据并将其设置在回收站视图上我希望当用户单击该视图时，将打开一个警报对话框，它会询问他是否要删除。如果是，视图将被删除。任何人都可以帮助我如何实现它吗？

这是我的主要活动代码

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        var todolist= mutableListOf<Todo>()
//            Todo("c",false),
           /* Todo("java",true),
            Todo("python",false),
            Todo("c#",false),
            Todo("c++",true),
            Todo("json",false),
            Todo("web dev",true),
            Todo("kotlin",true)*/

        val adapter=TodoAdapter(todolist)
        rvTodos.adapter=adapter
        rvTodos.layoutManager=LinearLayoutManager(this)
        btnAddTodo.setOnClickListener{
            val title=etTodo.text.toString()
            if(title==""){
                val builder = AlertDialog.Builder(this)
                builder.setTitle("Alart")
                builder.setMessage("Title can't be empty")

                builder.setPositiveButton("OK") { dialog, which ->
                    // Handle positive button click

                }

                builder.setNegativeButton("Cancel") { dialog, which ->
                    Toast.makeText(this,"set title first",Toast.LENGTH_LONG).show()
                }

                val alertDialog = builder.create()
                alertDialog.show()

            }
            else{
                val todo=Todo(title,false)
                todolist.add(todo)
                adapter.notifyItemInserted(todolist.size-1)
            }
        }
    }
}

这里是适配器类

class TodoAdapter(val todos: List<Todo>) : RecyclerView.Adapter<TodoAdapter.TodoViweholder>(){
    inner class TodoViweholder(itemView: View):RecyclerView.ViewHolder(itemView)

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): TodoViweholder {
        val view=LayoutInflater.from(parent.context).inflate(R.layout.item_todo,parent,false)
        return TodoViweholder(view)
    }

    override fun onBindViewHolder(holder: TodoViweholder, position: Int) {
            holder.itemView.apply {
               tvTitle.text=todos[position].title
                cbDone.isChecked=todos[position].isChecked
            }
    }

    override fun getItemCount(): Int {
        return todos.size
    }
}

回收器结构的 XML

<androidx.constraintlayout.widget.ConstraintLayout 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:padding="16dp"
    android:background="@color/black"
    android:id="@+id/structure"
    android:layout_marginBottom="5dp"
    android:layout_height="100dp">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="Title"
        android:textColor="@color/white"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/cbDone"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <CheckBox
        android:id="@+id/cbDone"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

这是主要的活动布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    android:padding="16dp"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rvTodos"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintBottom_toTopOf="@+id/etTodo"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.appcompat.widget.AppCompatButton
        android:id="@+id/btnAddTodo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="4dp"
        android:text="New Todo"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <EditText
        android:id="@+id/etTodo"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:hint="set title"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/btnAddTodo"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

我在这里假设您需要在回收站视图的每个视图上显示弹出窗口，并将决定是否需要删除该视图。

为此，您可以在

TodoAdapter#onBindViewHolder()

类中为每个 ViewHolder 项目添加一个点击监听器，如下所示：

holder.itemView.apply {
  tvTitle.text=todos[position].title
  cbDone.isChecked=todos[position].isChecked
  clickListener = OnClickListener {
    // <code to build and show your expected dialog here on view click>

    // In dialog builder, on button click remove entry from the adapter list and notify it like as follow.   
    builder.setPositiveButton("OK") { dialog, which ->
    todos.remove(holder.getPosition())
    notifyDatasetChanged()
  } 
}