如何通过编程为Android Spinner项目设置文本大小？

Question

我的情况似乎与谷歌上发现的100万个问题（与spinner相关）有点不同，google上的主要解决方案只是为spinner项目创建自定义xml。

Spinner mySpinner = FindViewById<Spinner>(Resource.Id.mySpinner);
List<string> languages = new List<string>();
Translation.LoadAvailableLanguages(out languages);
var adapter = new ArrayAdapter(this, Android.Resource.Layout.SimpleSpinnerItem, languages);
adapter.SetDropDownViewResource(Resource.Layout.spinner_item);
mySpinner.Adapter = adapter;

adapter.GetDropDownView(int position, View convertView, ViewGroup parent);

位置int：我们想要其视图的项的索引。

convertView视图：如果可能的话，要重用的旧视图。注意：在使用之前，您应该检查此视图是否为非空视图并具有适当的类型。如果无法转换此视图以显示正确的数据，此方法可以创建新视图。

父ViewGroup：此视图最终将附加到的父视图

(mySpinner.GetChildAt(n) as TextView).SetTextSize(Android.Util.ComplexUnitType.Px, 100);

Edit2:解决方案
基于公认的答案，我已经将Java for android代码转换为C#/Xamarin for android

class SpinnerStringAdapter: Android.Widget.ArrayAdapter {
    /// <summary>
    /// Array items' text height in screen pixels
    /// </summary>
    private int ActualTextSize = 20;
    /// <summary>
    /// Display items as bold text
    /// </summary>
    private bool IsBold = false;
    /// <summary>
    /// Creates array adapter with custom sized text.
    /// </summary>
    /// <param name="AContext">The current context.</param>
    /// <param name="ALayoutID">The resource ID for a layout file containing a TextView to use when instantiating views.</param>
    /// <param name="AStringList">The string objects to represent in the ListView.</param>
    /// <param name="ADisplay">The display of the parent activity</param>
    /// <param name="ATextSize">The size of a text for the array items. Size in percents of Display height</param>
    public SpinnerStringAdapter(Context AContext, int ALayoutID, System.Collections.IList AStringList, Display ADisplay, double ATextSize, bool AIsBold):
    base(AContext, ALayoutID, AStringList) {            
        Android.Graphics.Point size = new Android.Graphics.Point();
        ADisplay.GetSize(size);
        int width = size.X;
        int height = size.Y;
        ActualTextSize = Convert.ToInt32(height * ATextSize / 100); // Convert percent to fraction and calculate actual height
        IsBold = AIsBold;
    }

    public override View GetDropDownView(int position, View convertView, ViewGroup parent) {                  
        TextView tv = (LayoutInflater.From(Context).Inflate(Resource.Layout.spinner_item, parent, false) as TextView);
        tv.SetTextSize(Android.Util.ComplexUnitType.Px, ActualTextSize);
        tv.SetText(GetItem(position).ToString(), TextView.BufferType.Normal);
        if ( IsBold ) {
            tv.SetTypeface(null, Android.Graphics.TypefaceStyle.Bold);
        }
        return tv;
    }

    public override View GetView(int position, View convertView, ViewGroup parent) {
        TextView tv = ( LayoutInflater.From(Context).Inflate(Resource.Layout.spinner_item, parent, false) as TextView );
        tv.SetTextSize(Android.Util.ComplexUnitType.Px, ActualTextSize);
        tv.SetText(GetItem(position).ToString(), TextView.BufferType.Normal);
        if ( IsBold ) {
            tv.SetTypeface(null, Android.Graphics.TypefaceStyle.Bold);
        }
        return tv;
    }
}

Answer 1

首先，您可以创建一个扩展ArrayAdapter的自定义适配器类。通过这种方式，您可以在内部对“Get DropDownView”进行覆盖，以便更改下拉弹出窗口的显示（注意，您需要定义“CustomSpinnerItem.xml”，在本例中只使用一个TextView ej textview1)

@Override
public View getDropDownView(int position, View convertView, ViewGroup parent)
{
    View v = getLayoutInflater().inflate(R.layout.customspinneritem, parent, false);
    TextView tv = (TextView) v.findViewById(R.id.textview1);
    tv.setTextSize(**whatever**);
    tv.setText(languages[position]);
    return v;
}

如果您想在单击旋转器之前更改它的显示，要重写的一个函数是“获取视图（int position,View convertView,ViewGroup parent）”