Question

我将一个包含7个项目的列表传递给recyclerview，它只绑定了最后一个项目。通过使用日志记录，我看到getItemCount（）返回7，但onBindViewHolder只被调用一次。我知道（再次通过记录）我传递给适配器的列表是完整的列表。

请你帮我找出为什么只显示最后一个元素而不是整个列表。谢谢。

活动代码：

class HabitActivity : AppCompatActivity() {
    var adapter: ListHabitsAdapter? = null
    private var habitList: ArrayList<Habit>? = null
    private var habitListItems: ArrayList<Habit>? = null
    private var layoutManager: RecyclerView.LayoutManager? = null

    var dbHandler:HabitDataAdapter? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_habit)

        // Initialize the Class global variables
        //val mContext = applicationContext

        dbHandler = HabitDataAdapter(this)
        habitList = ArrayList<Habit>()
        habitListItems = ArrayList()
        layoutManager = LinearLayoutManager(this)
        adapter = ListHabitsAdapter(habitListItems!!,this)

        // Set up the RecyclerView
        habitListRecyclerViewID.layoutManager = layoutManager
        habitListRecyclerViewID.adapter = adapter

        // Load the chores
        habitList = dbHandler!!.readHabits()

        habitList!!.reverse()

        for (h in habitList!!.iterator()){
            var habit = Habit()
            habit.habitName = h.habitName
            habit.habitActive = h.habitActive
            habit.habitID = h.habitID
            habitListItems!!.add(habit)

            ///adapter!!.notifyDataSetChanged()
        }
        adapter!!.notifyDataSetChanged()
        printList(habitListItems!!)
    }

    //TODO - Remove debug before production
    fun printList(list:ArrayList<Habit>){
        for (i in 0..list.size - 1){
            Log.d(DEBUG, "${list[i].habitName} has ID ${list[i].habitID}")
        }
    }

    fun addHabit(view: View) {
        var popUpResult:String?=null
        var db = HabitDataAdapter(applicationContext)

        // pop up a dialog
        var promptView:View = layoutInflater.inflate(R.layout.habit_pop_up, null)
        var builder:AlertDialog.Builder =AlertDialog.Builder(this)
        builder.setView(promptView)
        builder.setTitle("Create a Habit")
        builder.setNeutralButton("CANCEL", DialogInterface.OnClickListener({
            dialog, which -> Toast.makeText(this,"Boo",Toast.LENGTH_LONG).show()
        }))
        builder.setPositiveButton("OK", DialogInterface.OnClickListener(){
            dialog, which ->
            var habitField = promptView.editText.text.toString()
            db.createHabit(habitField)
            Toast.makeText(this,habitField,Toast.LENGTH_LONG).show()

        })

        builder.show()

    }

    fun deleteHabit(view: View) {

    }

    fun loadMain(view: View){
        var intent = Intent(this, MainActivity::class.java)
        startActivity(intent)
    }

这是ListHabitAdapter：

class ListHabitsAdapter(val list:ArrayList<Habit>, context: Context): RecyclerView.Adapter<ListHabitsAdapter.ViewHolder>() {

    val mContext = context

    override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): ViewHolder {
        val view = LayoutInflater.from(mContext)
                .inflate(R.layout.habit_list_file, parent, false)

        return ViewHolder(view, mContext, list)
    }

    override fun onBindViewHolder(holder: ViewHolder?, position: Int) {
        Log.d(DEBUG,"Starting to Bind ${list[position]}")
        holder?.bindViews(list[position])
    }

    override fun getItemCount(): Int {
        Log.d(DEBUG,"getItemCount = ${list.size}")
        return list.size
    }


    inner class ViewHolder(itemView:View, context: Context, list: ArrayList<Habit>): RecyclerView.ViewHolder(itemView), View.OnClickListener {

        var mContext = context
        var mList = list

        var habitName = itemView.findViewById<TextView>(R.id.habitNameID)
        var deleteButton = itemView.findViewById<ImageButton>(R.id.habitDeleteButton)
        var doneButton = itemView.findViewById<ImageButton>(R.id.habitActiveButton)

        fun bindViews(habit: Habit){
            habitName.text = habit.habitName

            deleteButton.setOnClickListener(this)
            doneButton.setOnClickListener(this)
        }

        override fun onClick(v: View?) {
            var mPosition:Int = adapterPosition
            var habit = mList[mPosition]

            Log.d(DEBUG, habitName.text.toString())

            when(v!!.id){
                deleteButton.id -> Log.d(DEBUG,"delete button clicked")
                doneButton!!.id -> Log.d(DEBUG,"done button clicked")
            }
        }

    }
}

布局的XML：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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">

    <RelativeLayout
        android:id="@+id/habitListFileID"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <ImageButton
            android:id="@+id/habitActiveButton"
            android:layout_width="40dp"
            android:layout_height="40dp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:srcCompat="@android:drawable/checkbox_on_background"
            tools:layout_editor_absoluteX="2dp"
            tools:layout_editor_absoluteY="0dp" />

        <ImageButton
            android:id="@+id/habitDeleteButton"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:layout_toEndOf="@+id/habitNameID"
            app:srcCompat="@android:drawable/btn_dialog"
            tools:layout_editor_absoluteX="327dp"
            tools:layout_editor_absoluteY="0dp" />

        <TextView
            android:id="@+id/habitNameID"
            android:layout_width="281dp"
            android:layout_height="wrap_content"
            android:layout_marginLeft="52dp"
            android:layout_marginTop="8dp"
            android:text="TextView"
            android:textSize="18sp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </RelativeLayout>

</android.support.constraint.ConstraintLayout>

Answer 1

根据我的 above comment ，只需将ConstraintLayout身高调为android:layout_height="wrap_content"

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="wrap_content">

只有最后一个元素添加到Android中的RecyclerView（Kotlin）

1 个答案: