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;
        }
    }

//...
}

下面是一个覆盖Spinner视图的通用解决方案。它重写setAdapter()以将初始位置设置为-1，并代理提供的SpinnerAdapter以显示位置小于0的提示字符串。

这已经在Android 1.5到4.2上进行了测试，但买家要小心!因为这个解决方案依赖于反射来调用私有的AdapterView.setNextSelectedPositionInt()和AdapterView.setSelectedPositionInt()，所以它不能保证在未来的操作系统更新中工作。这似乎是有可能的，但这绝不是保证的。

通常我不会宽恕这样的事情，但这个问题已经被问了很多次了，这似乎是一个足够合理的要求，我认为我应该发布我的解决方案。

/**
 * A modified Spinner that doesn't automatically select the first entry in the list.
 *
 * Shows the prompt if nothing is selected.
 *
 * Limitations: does not display prompt if the entry list is empty.
 */
public class NoDefaultSpinner extends Spinner {

    public NoDefaultSpinner(Context context) {
        super(context);
    }

    public NoDefaultSpinner(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public NoDefaultSpinner(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void setAdapter(SpinnerAdapter orig ) {
        final SpinnerAdapter adapter = newProxy(orig);

        super.setAdapter(adapter);

        try {
            final Method m = AdapterView.class.getDeclaredMethod(
                               "setNextSelectedPositionInt",int.class);
            m.setAccessible(true);
            m.invoke(this,-1);

            final Method n = AdapterView.class.getDeclaredMethod(
                               "setSelectedPositionInt",int.class);
            n.setAccessible(true);
            n.invoke(this,-1);
        } 
        catch( Exception e ) {
            throw new RuntimeException(e);
        }
    }

    protected SpinnerAdapter newProxy(SpinnerAdapter obj) {
        return (SpinnerAdapter) java.lang.reflect.Proxy.newProxyInstance(
                obj.getClass().getClassLoader(),
                new Class[]{SpinnerAdapter.class},
                new SpinnerAdapterProxy(obj));
    }



    /**
     * Intercepts getView() to display the prompt if position < 0
     */
    protected class SpinnerAdapterProxy implements InvocationHandler {

        protected SpinnerAdapter obj;
        protected Method getView;


        protected SpinnerAdapterProxy(SpinnerAdapter obj) {
            this.obj = obj;
            try {
                this.getView = SpinnerAdapter.class.getMethod(
                                 "getView",int.class,View.class,ViewGroup.class);
            } 
            catch( Exception e ) {
                throw new RuntimeException(e);
            }
        }

        public Object invoke(Object proxy, Method m, Object[] args) throws Throwable {
            try {
                return m.equals(getView) && 
                       (Integer)(args[0])<0 ? 
                         getView((Integer)args[0],(View)args[1],(ViewGroup)args[2]) : 
                         m.invoke(obj, args);
            } 
            catch (InvocationTargetException e) {
                throw e.getTargetException();
            } 
            catch (Exception e) {
                throw new RuntimeException(e);
            }
        }

        protected View getView(int position, View convertView, ViewGroup parent) 
          throws IllegalAccessException {

            if( position<0 ) {
                final TextView v = 
                  (TextView) ((LayoutInflater)getContext().getSystemService(
                    Context.LAYOUT_INFLATER_SERVICE)).inflate(
                      android.R.layout.simple_spinner_item,parent,false);
                v.setText(getPrompt());
                return v;
            }
            return obj.getView(position,convertView,parent);
        }
    }
}

如果您在从数据库游标填充项时遇到此问题，

我在这个SO答案中找到的最简单的解决方案:

在游标适配器查询中使用UNION，并将id= -1的附加项添加到查询结果中，而不真正将其添加到DB中:

喜欢的东西:

db.rawQuery("SELECT iWorkerId as _id, nvLastName as name  FROM  Worker
w  UNION  SELECT -1 as _id , '' as name",null);

如果选择的项目是-1，那么它是默认值。否则 这是桌子上的记录。

我昨天遇到了同样的问题，不想向ArrayAdapter添加隐藏项或使用反射，这工作得很好，但有点脏。

在阅读了许多帖子和尝试之后，我通过扩展ArrayAdapter和覆盖getView方法找到了一个解决方案。

import android.content.Context;
import android.support.annotation.NonNull;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;

/**
 * A SpinnerAdapter which does not show the value of the initial selection initially,
 * but an initialText.
 * To use the spinner with initial selection instead call notifyDataSetChanged().
 */
public class SpinnerAdapterWithInitialText<T> extends ArrayAdapter<T> {

    private Context context;
    private int resource;

    private boolean initialTextWasShown = false;
    private String initialText = "Please select";

    /**
     * Constructor
     *
     * @param context The current context.
     * @param resource The resource ID for a layout file containing a TextView to use when
     *                 instantiating views.
     * @param objects The objects to represent in the ListView.
     */
    public SpinnerAdapterWithInitialText(@NonNull Context context, int resource, @NonNull T[] objects) {
        super(context, resource, objects);
        this.context = context;
        this.resource = resource;
    }

    /**
     * Returns whether the user has selected a spinner item, or if still the initial text is shown.
     * @param spinner The spinner the SpinnerAdapterWithInitialText is assigned to.
     * @return true if the user has selected a spinner item, false if not.
     */
    public boolean selectionMade(Spinner spinner) {
        return !((TextView)spinner.getSelectedView()).getText().toString().equals(initialText);
    }

    /**
     * Returns a TextView with the initialText the first time getView is called.
     * So the Spinner has an initialText which does not represent the selected item.
     * To use the spinner with initial selection instead call notifyDataSetChanged(),
     * after assigning the SpinnerAdapterWithInitialText.
     */
    @Override
    public View getView(int position, View recycle, ViewGroup container) {
        if(initialTextWasShown) {
            return super.getView(position, recycle, container);
        } else {
            initialTextWasShown = true;
            LayoutInflater inflater = LayoutInflater.from(context);
            final View view = inflater.inflate(resource, container, false);

            ((TextView) view).setText(initialText);

            return view;
        }
    }
}

Android在初始化Spinner时所做的，是在为T[]对象中的所有项目调用getView之前为所选项目调用getView。 SpinnerAdapterWithInitialText在第一次调用时返回带有initialText的TextView。 其他时间都调用super。getView是ArrayAdapter的getView方法如果你正常使用Spinner，它会被调用。

要找出用户是否选择了一个微调项，或者微调器是否仍然显示initialText，请调用selectionMade并移交适配器分配给的微调器。

public AdapterView.OnItemSelectedListener instructorSpinnerListener = new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView << ? > adapterView, View view, int i, long l) {
        String selectedInstructorName = adapterView.getItemAtPosition(i).toString();
        if (selectedInstructorName.equals("[Select Instructor]")) {
            instructorSpinnerAdapter.clear();
            for (Offering offering: allOfferingsList)
                instructorSpinnerAdapter.add(offering);
        } else {
            instructorSpinnerAdapter.clear();
        }
    }

    @Override
    public void onNothingSelected(AdapterView<< ? > adapterView) {
        adapterView.setSelection(0);

        // Toast.makeText(getApplicationContext(), "Why?", Toast.LENGTH_SHORT).show();
    }
};

你可以做的是装饰你的SpinnerAdapter与一个显示“选择选项…”视图，以便旋转器显示时不选择任何内容。

这里是一个工作的例子测试Android 2.3，和4.0(它不使用兼容性库，所以它应该是好的一段时间)，因为它是一个装饰器，它应该很容易改造现有的代码，它与CursorLoaders工作也很好。(当然是在包装的cursorAdapter上交换光标…)

有一个Android漏洞使得重用视图有点困难。(所以你必须使用setTag或其他东西来确保你的convertView是正确的。)Spinner不支持多种视图类型

代码注释:2个构造函数

这允许您使用标准提示符或定义您自己的“nothing selected”作为第一行，或两者都有，或没有。(注意:有些主题为旋转器显示下拉菜单，而不是对话框。下拉菜单通常不会显示提示)

你定义了一个“看起来”像提示符的布局，例如，灰色…

使用标准提示符(注意没有选择任何内容):

或者加上提示符和动态的东西(也可以没有提示符):

上面例子中的用法

Spinner spinner = (Spinner) findViewById(R.id.spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.planets_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setPrompt("Select your favorite Planet!");

spinner.setAdapter(
      new NothingSelectedSpinnerAdapter(
            adapter,
            R.layout.contact_spinner_row_nothing_selected,
            // R.layout.contact_spinner_nothing_selected_dropdown, // Optional
            this));

contact_spinner_row_nothing_selected.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    style="?android:attr/spinnerItemStyle"
    android:singleLine="true"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ellipsize="marquee"
    android:textSize="18sp"
    android:textColor="#808080"
    android:text="[Select a Planet...]" />

NothingSelectedSpinnerAdapter.java

import android.content.Context;
import android.database.DataSetObserver;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListAdapter;
import android.widget.SpinnerAdapter;

/**
 * Decorator Adapter to allow a Spinner to show a 'Nothing Selected...' initially
 * displayed instead of the first choice in the Adapter.
 */
public class NothingSelectedSpinnerAdapter implements SpinnerAdapter, ListAdapter {

    protected static final int EXTRA = 1;
    protected SpinnerAdapter adapter;
    protected Context context;
    protected int nothingSelectedLayout;
    protected int nothingSelectedDropdownLayout;
    protected LayoutInflater layoutInflater;

    /**
     * Use this constructor to have NO 'Select One...' item, instead use
     * the standard prompt or nothing at all.
     * @param spinnerAdapter wrapped Adapter.
     * @param nothingSelectedLayout layout for nothing selected, perhaps
     * you want text grayed out like a prompt...
     * @param context
     */
    public NothingSelectedSpinnerAdapter(
      SpinnerAdapter spinnerAdapter,
      int nothingSelectedLayout, Context context) {

        this(spinnerAdapter, nothingSelectedLayout, -1, context);
    }

    /**
     * Use this constructor to Define your 'Select One...' layout as the first
     * row in the returned choices.
     * If you do this, you probably don't want a prompt on your spinner or it'll
     * have two 'Select' rows.
     * @param spinnerAdapter wrapped Adapter. Should probably return false for isEnabled(0)
     * @param nothingSelectedLayout layout for nothing selected, perhaps you want
     * text grayed out like a prompt...
     * @param nothingSelectedDropdownLayout layout for your 'Select an Item...' in
     * the dropdown.
     * @param context
     */
    public NothingSelectedSpinnerAdapter(SpinnerAdapter spinnerAdapter,
            int nothingSelectedLayout, int nothingSelectedDropdownLayout, Context context) {
        this.adapter = spinnerAdapter;
        this.context = context;
        this.nothingSelectedLayout = nothingSelectedLayout;
        this.nothingSelectedDropdownLayout = nothingSelectedDropdownLayout;
        layoutInflater = LayoutInflater.from(context);
    }

    @Override
    public final View getView(int position, View convertView, ViewGroup parent) {
        // This provides the View for the Selected Item in the Spinner, not
        // the dropdown (unless dropdownView is not set).
        if (position == 0) {
            return getNothingSelectedView(parent);
        }
        return adapter.getView(position - EXTRA, null, parent); // Could re-use
                                                 // the convertView if possible.
    }

    /**
     * View to show in Spinner with Nothing Selected
     * Override this to do something dynamic... e.g. "37 Options Found"
     * @param parent
     * @return
     */
    protected View getNothingSelectedView(ViewGroup parent) {
        return layoutInflater.inflate(nothingSelectedLayout, parent, false);
    }

    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        // Android BUG! http://code.google.com/p/android/issues/detail?id=17128 -
        // Spinner does not support multiple view types
        if (position == 0) {
            return nothingSelectedDropdownLayout == -1 ?
              new View(context) :
              getNothingSelectedDropdownView(parent);
        }

        // Could re-use the convertView if possible, use setTag...
        return adapter.getDropDownView(position - EXTRA, null, parent);
    }

    /**
     * Override this to do something dynamic... For example, "Pick your favorite
     * of these 37".
     * @param parent
     * @return
     */
    protected View getNothingSelectedDropdownView(ViewGroup parent) {
        return layoutInflater.inflate(nothingSelectedDropdownLayout, parent, false);
    }

    @Override
    public int getCount() {
        int count = adapter.getCount();
        return count == 0 ? 0 : count + EXTRA;
    }

    @Override
    public Object getItem(int position) {
        return position == 0 ? null : adapter.getItem(position - EXTRA);
    }

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

    @Override
    public int getViewTypeCount() {
        return 1;
    }

    @Override
    public long getItemId(int position) {
        return position >= EXTRA ? adapter.getItemId(position - EXTRA) : position - EXTRA;
    }

    @Override
    public boolean hasStableIds() {
        return adapter.hasStableIds();
    }

    @Override
    public boolean isEmpty() {
        return adapter.isEmpty();
    }

    @Override
    public void registerDataSetObserver(DataSetObserver observer) {
        adapter.registerDataSetObserver(observer);
    }

    @Override
    public void unregisterDataSetObserver(DataSetObserver observer) {
        adapter.unregisterDataSetObserver(observer);
    }

    @Override
    public boolean areAllItemsEnabled() {
        return false;
    }

    @Override
    public boolean isEnabled(int position) {
        return position != 0; // Don't allow the 'nothing selected'
                                             // item to be picked.
    }

}