问题
in my app,I want to create SpinnerList using CustomAdapter class,For this i wrote below code but when I tap on spinner list then array-List images are not loading in spinner-list as like my below screen why this problem is coming?
main_layout.xml:-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:text="Category:"
android:layout_marginBottom="5dp"/>
<Spinner
android:id="@+id/spinner"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
MainActivity:-
public class MainActivity extends AppCompatActivity {
public static final String[] titles = new String[] { "Strawberry",
"Banana", "Orange", "Hello" };
public static final Integer[] images = { R.drawable.image1,
R.drawable.image2, R.drawable.image3, R.drawable.image4 };
Spinner spinner;
List<RowItem> rowItems;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
rowItems = new ArrayList<RowItem>();
for (int i = 0; i < titles.length; i++) {
RowItem item = new RowItem(titles[i],images[i]);
rowItems.add(item);
}
spinner = (Spinner)findViewById(R.id.spinner);
CustomAdapter adapter = new CustomAdapter(MainActivity.this,
R.layout.listitems_layout, R.id.title, rowItems);
spinner.setAdapter(adapter);
}
}
listitems_layout.xml:-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<ImageView
android:id="@+id/icon"
android:layout_width="80dp"
android:layout_height="80dp"
android:src="@drawable/image1"
android:padding="10dp"
/>
<TextView
android:layout_marginTop="30dp"
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/icon"
android:textColor="#CC0033"
android:text="Strawberry"
android:textSize="16dp" />
</LinearLayout>
CustomAdapter:-
package com.example.venkat.spinnerexample1;
import android.app.Activity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.view.LayoutInflater;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.List;
public class CustomAdapter extends ArrayAdapter<RowItem> {
LayoutInflater flater;
public CustomAdapter(Activity context,int resouceId, int textviewId, List<RowItem> list){
super(context,resouceId,textviewId, list);
flater = context.getLayoutInflater();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
RowItem rowItem = getItem(position);
View rowview = flater.inflate(R.layout.listitems_layout,null,true);
TextView txtTitle = (TextView) rowview.findViewById(R.id.title);
txtTitle.setText(rowItem.getTitle());
ImageView imageView = (ImageView) rowview.findViewById(R.id.icon);
imageView.setImageResource(rowItem.getImageId());
return rowview;
}
}
RowItem:-
package com.example.venkat.spinnerexample1;
public class RowItem {
private int ImageId;
private String Title;
public RowItem(String Title,int ImageId){
this.Title = Title;
this.ImageId = ImageId;
}
public String getTitle(){
return Title;
}
public void setTitle(String Title){
this.Title = Title;
}
public int getImageId(){
return ImageId;
}
public void setImageId(int ImageId){
this.ImageId = ImageId;
}
@Override
public String toString() {
return Title ;
}
}
screen:- ---
回答1:
Inside your adapter constructor, send the id of textview also
public CustomAdapter(Activity context,int resouceId, int textviewId, List<RowItem> list){
super(context,resouceId,textviewId, list);
flater = context.getLayoutInflater();
}
call it by
CustomAdapter adapter = new CustomAdapter(MainActivity.this,
R.layout.listitems_layout, R.id.title, rowItems);
EDIT Your images are not showing because you didn't override the getDropdownView() method. This method decides the layout of child when dropdown is visible. So add this method to your adapter
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
if(convertView == null){
convertView = flater.inflate(R.layout.list_itemslayout,parent, false);
}
RowItem rowItem = getItem(position);
TextView txtTitle = (TextView) convertView.findViewById(R.id.title);
txtTitle.setText(rowItem.getTitle());
ImageView imageView = (ImageView) convertView.findViewById(R.id.icon);
imageView.setImageResource(rowItem.getImageId());
return convertView;
}
Suggestion in your getView() put a check for (convertview == null). It might not have any impact on this small adapter but in case your adapter is having more items, it will impact the performance.
EDIT To put your spinner dropdown below the anchor, use
android:overlapAnchor="false" inside your spinner
回答2:
Change your adapter like this
public class CustomAdapter extends ArrayAdapter<RowItem> {
LayoutInflater flater;
public CustomAdapter(Activity context, int resouceId, int textviewId, List<RowItem> list){
super(context,resouceId,textviewId, list);
// flater = context.getLayoutInflater();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
return rowview(convertView,position);
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
return rowview(convertView,position);
}
private View rowview(View convertView , int position){
RowItem rowItem = getItem(position);
viewHolder holder ;
View rowview = convertView;
if (rowview==null) {
holder = new viewHolder();
flater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
rowview = flater.inflate(R.layout.listitems_layout, null, false);
holder.txtTitle = (TextView) rowview.findViewById(R.id.title);
holder.imageView = (ImageView) rowview.findViewById(R.id.icon);
rowview.setTag(holder);
}else{
holder = (viewHolder) rowview.getTag();
}
holder.imageView.setImageResource(rowItem.getImageId());
holder.txtTitle.setText(rowItem.getTitle());
return rowview;
}
private class viewHolder{
TextView txtTitle;
ImageView imageView;
}
}
来源：https://stackoverflow.com/questions/35983176/how-to-create-spinner-list-using-customadapter-in-android