XML文件:

<Spinner android:id="@+id/locationSpinner"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:prompt="@string/select_location" />

活动:

private Spinner featuresSelection;
private ArrayAdapter<CharSequence> featuresAdapter;
private List<CharSequence> featuresList;

onCreate:

featuresList = new ArrayList<CharSequence>();
featuresAdapter = new ArrayAdapter<CharSequence>(this,
  android.R.layout.simple_spinner_item, featuresList);
featuresAdapter.setDropDownViewResource(
  android.R.layout.simple_spinner_dropdown_item);
featuresSelection = ((Spinner) yourActivity.this
  .findViewById(R.id.locationSpinner));
featuresSelection.setAdapter(featuresAdapter);
featuresSelection.setOnItemSelectedListener(
  new MyOnItemSelectedListener());

某些函数(以编程方式向适配器添加内容)>

featuresAdapter.add("some string");

现在你有一个空的转轮，你可以写代码不打开对话框，如果是空的。或者他们可以反击。但是您也可以在运行时用函数或另一个列表填充它。

参考上述答案之一:https://stackoverflow.com/a/23005376/1312796

我添加了我的代码来修复一个小错误。哪里没有数据检索..如何显示提示文本..!

这是我的诀窍……我觉得挺好用的。！

试着把你的旋转器在一个relative_layout和对齐的Textview与你的旋转器和发挥Textview的可见性(SHOW/HIDE)每当旋转器的适配器加载或空..像这样:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="20dp"
android:background="#ededed"
android:orientation="vertical">



    <TextView
        android:id="@+id/txt_prompt_from"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:textColor="@color/gray"
        android:textSize="16sp"
        android:layout_alignStart="@+id/sp_from"
        android:text="From"
        android:visibility="gone"/>

    <Spinner
        android:id="@+id/sp_from"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        />

代码如下: txt_from = (TextView) rootView.findViewById(R.id.txt_prompt_from); 在转轮适配器加载并为空前后调用此方法。 setPromptTextViewVisibility ();//正确或错误 setPromptTextViewVisibility (boolean visible) ｛ 如果(可见的) ｛ txt_from.setVisibility (View.VISIBLE); ｝ 其他的 ｛ txt_from.setVisibility (View.INVISIBLE); ｝ ｝

此外，还有一个简单的技巧来显示默认值:

你可以在列表中添加一个默认值，然后使用list. addall (yourCollection)添加所有的集合;

下面是可操作的示例代码:

List<FuelName> fuelList = new ArrayList<FuelName>();
                    fuelList.add(new FuelName(0,"Select One"));
                    fuelList.addAll(response.body());
                    ArrayAdapter adapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_spinner_item, fuelList);
                    //fuelName.setPrompt("Select Fuel");
                    fuelName.setAdapter(adapter);

When extending SpinnerAdapter, you override two View-producing methods, getView(int, View, ViewGroup) and getDropDownView(int, View, ViewGroup). The first one supplies the View inserted into the Spinner itself; the second supplies the View in the drop-down list (as the name suggests). You can override the getView(...) so that, until an item has been selected, it displays a TextView containing a prompt; then, when you detect an item has been selected, you change it to display a TextView corresponding to that.

public class PromptingAdapter extends SpinnerAdapter {

    //... various code ...

    private boolean selectionmade = false;

    //call this method from the OnItemSelectedListener for your Spinner
    public setSelectionState(boolean b) {
        selectionmade = b;
    }

    @Override
    public View getView(int position, View recycle, ViewGroup container) {
        if(selectionmade) {
            //your existing code to supply a View for the Spinner
            //you could even put "return getDropDownView(position, recycle, container);"
        }
        else {
            View output;
            if(recycle instanceof TextView) {
                 output = recycle;
            }
            else {
                 output = new TextView();
                 //and layout stuff
            }
            output.setText(R.string.please_select_one);
            //put a string "please_select_one" in res/values/strings.xml
            return output;
        }
    }

//...
}

我得到了同样的问题旋转，与一个空的选择，我找到了一个更好的解决方案。看看这段简单的代码。

Spinner lCreditOrDebit = (Spinner)lCardPayView.findViewById(R.id.CARD_TYPE);
spinneradapter lAdapter = 
  new spinneradapter(
    BillPayScreen.this, 
    ndroid.R.layout.simple_spinner_item,getResources().getStringArray(R.array.creditordebit));
lAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
lCreditOrDebit.setAdapter(lAdapter);

这里spinneradapter是对arrayadapter的一个小定制。它是这样的:

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;

public class spinneradapter extends ArrayAdapter<String>{
    private Context m_cContext;
    public spinneradapter(Context context,int textViewResourceId, String[] objects) {
        super(context, textViewResourceId, objects);
        this.m_cContext = context;
    }

    boolean firsttime = true;
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if(firsttime){
            firsttime = false;
            //Just return some empty view
            return new ImageView(m_cContext);
        }
        //Let the array adapter take care of it this time.
        return super.getView(position, convertView, parent);
    }
}

首先，您可能对Spinner类的prompt属性感兴趣。如下图所示，“Choose a Planet”是可以用android在XML中设置的提示符:prompt=""。

我建议子类化Spinner，在这里您可以在内部维护两个适配器。一个适配器有“选择一个”选项，另一个真正的适配器(有实际的选项)，然后使用OnClickListener在选项对话框显示之前切换适配器。然而，在尝试实现这个想法后，我得出的结论是，你不能接收小部件本身的OnClick事件。

您可以将旋转器包装在不同的视图中，拦截视图上的单击，然后告诉CustomSpinner切换适配器，但这似乎是一种糟糕的hack。

你真的需要显示“选择一”吗?