in meiner App möchte ich SpinnerList mit der CustomAdapter-Klasse erstellen. Dazu habe ich den folgenden Code geschrieben, aber wenn ich auf die Spinner-Liste tippe, werden die Array-List-Bilder nicht in die Spinner-Liste geladen, wie auf meinem unteren Bildschirm. Warum tritt dieses Problem auf?
<?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>
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);
}
}
<?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>
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;
}
}
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 ;
}
}
Senden Sie in Ihrem Adapterkonstruktor auch die ID von textview
public CustomAdapter(Activity context,int resouceId, int textviewId, List<RowItem> list){
super(context,resouceId,textviewId, list);
flater = context.getLayoutInflater();
}
nennen Sie es durch
CustomAdapter adapter = new CustomAdapter(MainActivity.this,
R.layout.listitems_layout, R.id.title, rowItems);
EDIT Ihre Bilder werden nicht angezeigt, weil Sie die Methode getDropdownView () nicht überschrieben haben. Diese Methode legt das Layout des untergeordneten Elements fest, wenn das Dropdown-Menü angezeigt wird. Fügen Sie diese Methode Ihrem Adapter hinzu
@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;
}
Vorschlag Setzen Sie in Ihrem getView () ein Häkchen für (convertview == null). Dies hat möglicherweise keine Auswirkungen auf diesen kleinen Adapter. Wenn Ihr Adapter jedoch mehr Elemente enthält, wirkt sich dies auf die Leistung aus.
EDIT Um Ihr Spinner-Dropdown unter den Anker zu setzen, verwenden Sie
Android:overlapAnchor="false"
in deinem Spinner
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;
}
}