我的布局中有一个 Android Spinner 视图。我希望该微调器在关闭时仅显示一个文本项，但是当用户单击它时（即打开微调器对话框）我想为每个项目显示更广泛的信息，包括一个图标和一个附加的描述文本视图. 就像现在一样，微调器在两种状态下都显示了完全相同的布局（图标、标题 + 描述）。
如果我将 ArrayAdapter 附加到微调器，那么我可以访问称为“setDropDownViewResource”的东西，但这不一定是我需要的，因为我的微调器数据是从游标中获取的，而不是从任何类型的数组中获取的（我有，到目前为止，创建了我自己的适配器，扩展了 BaseAdapter）。
谁能帮助我？
您必须为 Spinner 创建一个自定义Adapter类并覆盖getView()正常关闭视图和getDropDownView()下拉列表视图的两种方法。两种方法都必须View为单个元素返回一个对象。
看看这个教程，它可能会帮助你入门。
我也遇到了问题。我没有覆盖课程，而是有一种更简单的方法来做到这一点。
但首先您需要了解适配器构造函数中的资源 id 与setDropDownViewResource(...). 例如，
SimpleAdapter adapter =
new SimpleAdapter(ab.getThemedContext(), data, R.layout.actionbar_dropdown, new String[] { "EventID", "Icon" },
new int[] { R.id.event_id, R.id.icon });
adapter.setDropDownViewResource(R.layout.actionbar_list_item);
R.layout.actionbar_dropdown是spinner和R.layout.actionbar_list_item每个列表项的样式。
我在这里使用了 SimpleAdapter，因为如果我使用 ArrayAdapter，xml 只能是单个 TextView。
R.layout.actionbar_list_item包含一个 id 为的 TextViewevent_id和一个 id 为 的 ImageView icon。
R.layout.actionbar_dropdown几乎完全一样actionbar_list_item，但后者的 ImageView 的可见性设置为GONE。
这样，每个列表项都有一个 textview 和一个 imageview，但您只会在微调器上看到一个 textview。
使用 Flo 链接的教程代码，我创建了以下 CustomSpinnerAdapter 以显示两组不同的字符串，一组在显示项目时，另一组在不显示时。我希望它可以帮助某人。
public class CustomSpinnerAdapter extends ArrayAdapter<String> {
Context mContext;
int mTextViewResourceId;
String[] mObjects;
String[] mShortNameObjects;
public CustomSpinnerAdapter(Context context, int textViewResourceId,
String[] objects, String[] shortNameObjects) {
super(context, textViewResourceId, objects);
mContext = context;
mTextViewResourceId = textViewResourceId;
mObjects = objects;
mShortNameObjects = shortNameObjects;
}
@Override
public View getDropDownView(int position, View convertView,
ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
TextView row = (TextView) inflater.inflate(mTextViewResourceId, parent, false);
row.setText(mObjects[position]);
return row;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
return getCustomView(position, convertView, parent);
}
public View getCustomView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
TextView row = (TextView) inflater.inflate(mTextViewResourceId, parent, false);
row.setText(mShortNameObjects[position]);
return row;
}
}
以及Fragment 内部的用法：
CustomSpinnerAdapter mSpinnerAdapter = new CustomSpinnerAdapter(getActivity(), R.layout.spinner_item, getResources().getStringArray(R.array.action_filter), getResources().getStringArray(R.array.action_filter_short_names));
最后，微调器项目的布局：
spinner_item.xml
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="18dip"
android:gravity="left"
android:textColor="@color/navdraw_list_item_background_default"
android:padding="5dip" />
仅使用您的替代布局设置下拉视图资源：
ArrayAdapter<String> genderAdapter = new ArrayAdapter<>(this, R.layout.adapter_spinner_white, Constants.GENDER);
genderAdapter.setDropDownViewResource(R.layout.adapter_spinner_white_dropdown);
view.setAdapter(genderAdapter);
对我来说，它只是一个带有额外填充的布局，因为我的微调器背景是圆形可绘制的，需要这个额外的空间。
setUpSpinner()在获取到 spinner 的引用后调用方法
// here is setUpSpinner method
private void setupSpinner() {
// Create adapter for spinner. The list options are from the String array it will use
// the spinner will use the default layout
ArrayAdapter spinnerAdapter = ArrayAdapter.createFromResource(this,
R.array.array_dropdown_options, android.R.layout.simple_spinner_item);
// Specify dropdown layout style - simple list view with 1 item per line
spinnerAdapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
// Apply the adapter to the spinner
spinner.setAdapter(spinnerAdapter);
// spinner is referenced spinner by finViewById.
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String selection = (String) parent.getItemAtPosition(position);
if (!TextUtils.isEmpty(selection)) {
if (selection.equals(getString(R.string.item_a))) {
// your code for selected item whose id equals to id to R.string.item_a
} else if (selection.equals(getString(R.string.item_b))) {
// your code
} else {
// your code
}
}
}
// Because AdapterView is an abstract class, onNothingSelected must be defined
@Override
public void onNothingSelected(AdapterView<?> parent) {
// code for nothing selected in dropdown
}
});
}
ArrayAdapter我尽可能多地扩展了哪些保存器的功能，只需将长描述设置为所选项目。
首先，我们需要一个新模型来为适配器供电。请注意，toString()返回shortDescription以便ArrayAdapter在下拉列表中显示简短描述：
data class DescriptiveArrayItem(val shortDescription: String, val longDescription: String) {
override fun toString(): String {
return shortDescription
}
}
其次，我们创建了我们的自定义适配器，它getView()在选择项目时覆盖并显示长描述（不幸的是，其中的许多字段和方法ArrayAdapter是私有的，所以我不得不复制它们）：
class DescriptiveArrayAdapter : ArrayAdapter<DescriptiveArrayItem> {
private var mResource: Int
private val mFieldId: Int
private val mContext: Context
private val mInflater: LayoutInflater
constructor(context: Context, resource: Int) : super(context, resource) {
mContext = context
mFieldId = 0
mInflater = LayoutInflater.from(context)
mResource = resource
}
constructor(context: Context, resource: Int, textViewResourceId: Int) : super(context, resource, textViewResourceId) {
mContext = context
mFieldId = textViewResourceId
mInflater = LayoutInflater.from(context)
mResource = resource
}
constructor(context: Context, resource: Int, objects: Array<out DescriptiveArrayItem>) : super(context, resource, objects) {
mContext = context
mFieldId = 0
mInflater = LayoutInflater.from(context)
mResource = resource
}
constructor(context: Context, resource: Int, textViewResourceId: Int, objects: Array<out DescriptiveArrayItem>) : super(context, resource, textViewResourceId, objects) {
mContext = context
mFieldId = textViewResourceId
mInflater = LayoutInflater.from(context)
mResource = resource
}
constructor(context: Context, resource: Int, objects: List<DescriptiveArrayItem>) : super(context, resource, objects) {
mContext = context
mFieldId = 0
mInflater = LayoutInflater.from(context)
mResource = resource
}
constructor(context: Context, resource: Int, textViewResourceId: Int, objects: List<DescriptiveArrayItem>) : super(context, resource, textViewResourceId, objects) {
mContext = context
mFieldId = textViewResourceId
mInflater = LayoutInflater.from(context)
mResource = resource
}
override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
return createViewFromResource(mInflater, position, convertView, parent, mResource)
}
private fun createViewFromResource(inflater: LayoutInflater, position: Int,
convertView: View?, parent: ViewGroup, resource: Int): View {
val text: TextView?
val view: View = convertView ?: inflater.inflate(resource, parent, false)
try {
if (mFieldId == 0) {
// If no custom field is assigned, assume the whole resource is a TextView
text = view as TextView
} else {
// Otherwise, find the TextView field within the layout
text = view.findViewById(mFieldId)
if (text == null) {
throw RuntimeException("Failed to find view with ID "
+ mContext.resources.getResourceName(mFieldId)
+ " in item layout")
}
}
} catch (e: ClassCastException) {
Log.e("ArrayAdapter", "You must supply a resource ID for a TextView")
throw IllegalStateException(
"ArrayAdapter requires the resource ID to be a TextView", e)
}
val item: DescriptiveArrayItem? = getItem(position)
text.text = item?.longDescription
return view
}
}