指定的 child 已经有一个 parent。您必须先在 child 的 parent 上调用 removeView()。 （带工具栏）

Question

我正在尝试将带有自定义适配器的微调器添加到工具栏，但遇到此错误： 指定的 child 已经有一个 parent。您必须先在 child 的 parent 上调用 removeView()。 这是我的微调适配器 class:

public class SpinnerAdapter extends BaseAdapter {
    ArrayList<ShopCartModel> list;
    Context context;
    LayoutInflater inflater;

    public SpinnerAdapter (Context c , ArrayList<ShopCartModel> list){
        this.context = c;
        this.list = list;
        inflater = (LayoutInflater.from(c));
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        convertView = inflater.inflate(R.layout.custom_spinner_item , null);
        TextView name = (TextView)convertView.findViewById(R.id.textView);
        ShopCartModel tmp = list.get(position);
        name.setText(tmp.getName());
        return convertView;
    }
}

这是我的主要 class，当我尝试将微调器添加到工具栏时：

public class ShopCartScreen extends AppCompatActivity implements AdapterView.OnItemSelectedListener{
    Spinner spin;
    ArrayList<ShopCartModel> shopCarts;
SpinnerAdapter spinnerAdapter;
    DBHelper db;
    ApartmentModel apartment;
    GetShopLists g;
    SharedPreferences preferences;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.shop_carts_list);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayShowTitleEnabled(false);


        items = (ListView)findViewById(R.id.shop_carts_lists);
        spin = (Spinner)findViewById(R.id.spinner);
        db = DBHelper.getInstance(this);
        preferences = getSharedPreferences("appData", 0);
        boolean flag = preferences.getBoolean("ShopCartListsLoadedFromDB" , false); //
        int apartmentNumber = preferences.getInt("apartmentNumber" , 0);
        apartment = new ApartmentModel(apartmentNumber);
        if(flag == true){
            shopCarts = db.getshopLists(apartment);
            spinnerAdapter = new    SpinnerAdapter(getApplicationContext(),shopCarts);
            spin.setAdapter(spinnerAdapter);
        }
        else{
            g = new GetShopLists(this, shopCarts , spin , spinnerAdapter);
            g.execute("this is where i set the items on the spinner");

            preferences = getSharedPreferences("appData", 0);
            SharedPreferences.Editor editor = preferences.edit();
            editor.putBoolean("ShopCartListsLoadedFromDB" , true);
            editor.apply();
        }
toolbar.addView(spin, 0); //this is where the application crushes

        spin.setOnItemSelectedListener(this);

    }

编辑：我的主要 xml 文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!--list of all shop carts of an apartment-->

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:minHeight="?attr/actionBarSize"
        android:background="#ff1e8622"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </android.support.v7.widget.Toolbar>

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="right"
        android:weightSum="1"
        android:id="@+id/newList"
        android:baselineAligned="false">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="@string/newList"
            android:id="@+id/textView"
            android:layout_weight="0.12"
            android:layout_gravity="center"
            />

        <ImageButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/imageButton"
            android:src="@android:drawable/ic_input_add"
            android:background="#ffffff"
            android:layout_marginLeft="@dimen/activity_horizontal_margin"
            android:layout_gravity="center"
            android:onClick="createNewList"
            />

    </LinearLayout>

    <Spinner
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/spinner" />

    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/shop_carts_lists"
        android:layout_gravity="center_horizontal"
        android:layout_below="@id/newList"
        android:paddingTop="10dp"/>

</LinearLayout>

和我的旋转器项目 xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/textView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:padding="@dimen/activity_horizontal_margin"
        android:text="Demo"
        android:textColor="#000" />
</LinearLayout>

Answer 1

因为某些布局中已经存在微调器。你可以通过两种类型来完成。

1. 删除 toolbar.addView(spin, 0); 行。

   或

2. 将微调器初始化更改为..

   旋转器旋转 = 新旋转器(YourACtivity.this);

并将其从布局中删除 xml。