android - 微调器下拉外边框

Question

如何为整个下拉菜单而不是项目本身设置边框？

期望:

也许看不清楚，但我对整个下拉菜单外的白色边框很感兴趣。见红字

现实:

spinner_item.xml:

<?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"
    android:background="@color/primary_blue_dark">

    <TextView
        android:id="@+id/tv_spinner_item"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="12dp"
        android:gravity="center_vertical|start"
        style="@style/sp_squared_style"/>

    <ImageView
        android:id="@+id/iv_underline"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginRight="12dp"
        android:layout_marginLeft="12dp"
        android:layout_marginBottom="6dp"
        android:background="@drawable/ic_underline"/>
</LinearLayout>

Answer 1

感谢 Ben-J 评论和 http://stackoverflow.com/questions/33222207/how-to-add-padding-to-drop-down-list-that-we-get-by-clicking-on-spinner answer 我使用此代码使用 ThemeOverlay.AppCompat.Light 子样式创建边框。

这将为外部列表覆盖创建填充，这将显示底层覆盖背景。您还需要为列表项设置一个明确的背景，这样它们就不会透明。

layout/main_layout.xml:

<Spinner xmlns:app="http://schemas.android.com/apk/res-auto"
  app:popupTheme="@style/LangList_SpinnerPopupOverlay" />

values/styles.xml:

<style name="LangList_SpinnerPopupOverlay" parent="ThemeOverlay.AppCompat.Light">
  <!-- border width -->
  <item name="android:padding">1dp</item>
  <!-- border color -->
  <item name="android:background">#f00</item>
</style>

layout/spinner_list_item.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="horizontal"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <TextView
    android:id="@+id/itemText"
    android:background="#fff"/>
</LinearLayout>

layout/spinner_view.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="horizontal"
  android:layout_width="match_parent"
  android:layout_height="match_parent">

  <TextView
    android:id="@+id/itemText"/>
</LinearLayout>

CustomListAdapter.java:

import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.TextView;

public class CustomListAdapter extends ArrayAdapter<CustomListItem> {

  private Context context;

  public CustomListAdapter(Context context, List<CustomListItem> items) {
    super(context, R.layout.spinner_list_item, items);
    this.context = context;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
    // spinner layout (when closed)
    int layoutId = R.layout.spinner_view;
    return createView(position, convertView, parent, layoutId);
  }

  @Override
  public View getDropDownView(int position, View convertView, ViewGroup parent) {
    // dropdown list layout
    int layoutId = R.layout.spinner_list_item;
    return createView(position, convertView, parent, layoutId);
  }

  private View createView(int position, View convertView, ViewGroup parent, int layoutId) {
    if (convertView == null) {
      LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
      convertView = inflater.inflate(layoutId, null);
    }

    TextView itemText = convertView.findViewById(R.id.itemText);

    CustomListItem item = getItem(position);
    if (item != null) {
      itemText.setText(item.getText());
    }

    return convertView;
  }

}