将 AlertDialog 与自动完成文本相结合

Question

所以我想做的是拥有一个 AlertDialog，用户可以在其中将自己的杂货添加到数据库中。我希望程序在用户输入时给出建议。我想将 AlertDialog 与 AutoCompleteTextView 结合起来。我在自动完成部分遵循了本指南 https://developer.android.com/reference/android/widget/AutoCompleteTextView.html，但我似乎做错了。

主要内容：

public void add(View caller) {

        MaterialAlertDialogBuilder mBuilder = new MaterialAlertDialogBuilder(mainActivity.this);
        mBuilder.setTitle(R.string.dialog_title);
        mBuilder.setView(R.layout.add_items_dialog);
        mBuilder.setMessage("Enter a grocery");

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_dropdown_item_1line, GROCERIES);
        AutoCompleteTextView textView = (AutoCompleteTextView) findViewById(R.id.name_text_field);
        textView.setAdapter(adapter);
        mBuilder.setPositiveButton("Add", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int which) {

            }
        });
        mBuilder.setNegativeButton(R.string.dismiss_label, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.dismiss();
            }
        });
        AlertDialog mDialog = mBuilder.create();
        mDialog.show();

add_items_dialog.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <com.google.android.material.textfield.TextInputLayout
        android:id="@+id/name_text_field"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/dp_16"
        android:layout_marginEnd="@dimen/dp_16"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:hint="@string/enter_text"
        android:textColorHint="@color/colorDarkGreen"
        style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox">

        <com.google.android.material.textfield.TextInputEditText
            android:id="@+id/et_input"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:inputType="text"
            android:singleLine="true" />

    </com.google.android.material.textfield.TextInputLayout>


</androidx.constraintlayout.widget.ConstraintLayout>

第 textView.setAdapter(adapter) 行出错：

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.AutoCompleteTextView.setAdapter(android.widget.ListAdapter)' on a null object reference

我猜这与将适配器设置为错误的文本视图有关，但也可能是完全不同的。有什么建议吗？

Answer 1

你需要改变mbuilder.addView(R.layout.add_itemes_dialog) 通过

View view =LayoutInflater.from(this).inflate(R.layout.add_itemes_dialog, null);
builder.setView(view);
// and to find your AutoCompleteTextView 
AutoCompleteTextView textView = (AutoCompleteTextView) view.findViewById(R.id.et_input);

并且在您的 xml 文件中将 TextInputEditText 更改为 MaterialAutoCompleteTextView，它应该可以工作

将 AlertDialog 与自动完成文本相结合

Combine AlertDialog with AutoCompleteText

java

android

autocompletetextview

android-alertdialog