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我在ArrayList上創建了數據對象shopObjects。我仔細檢查他們是否已滿。不是空的，並試圖創建一個適配器。這是我第一次這樣做，而且名單是空的。我不確定我做錯了什麼。LIstView適配器沒有顯示自定義適配器的內容
**CustomListAdapter.java**
public class CustomListAdapter extends ArrayAdapter<shopClass> {
ArrayList<shopClass> shopObjects;
private final int resource;
public CustomListAdapter(Context context, ArrayList<shopClass> PshopObjects, int resource) {
super(context, R.layout.list_row, PshopObjects);
shopObjects = PshopObjects;
this.resource = resource;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// We need to get the best view (re-used if possible) and then
// retrieve its corresponding ViewHolder, which optimizes lookup efficiency
View view = getWorkingView(convertView);
ViewHolder viewHolder = getViewHolder(view);
shopClass shop = getItem(position);
if (shopObjects == null) {
System.out.println("it is null on CustomListarrya");
}
// Setting the title view is straightforward
viewHolder.titleView.setText(shop.getName());
viewHolder.subTitleView.setText(shop.getDescription());
// TextView title = (TextView) alertView.findViewById(R.id.title);
// TextView description = (TextView) alertView.findViewById(R.id.description);
// LinearLayout bkgImage = (LinearLayout) alertView.findViewById(R.id.bkgImage);
//
// // getting movie data for the row
//
// // bkg image
//// bkgImage.setBackground();
//
// // title
// title.setText(shop.getName());
//
// // description
// description.setText(shop.getDescription());
return view;
}
private View getWorkingView(final View convertView) {
// The workingView is basically just the convertView re-used if possible
// or inflated new if not possible
View workingView = null;
if(null == convertView) {
final Context context = getContext();
final LayoutInflater inflater = (LayoutInflater)context.getSystemService
(Context.LAYOUT_INFLATER_SERVICE);
workingView = inflater.inflate(resource, null);
} else {
workingView = convertView;
}
return workingView;
}
private ViewHolder getViewHolder(final View workingView) {
// The viewHolder allows us to avoid re-looking up view references
// Since views are recycled, these references will never change
final Object tag = workingView.getTag();
ViewHolder viewHolder = null;
if(null == tag || !(tag instanceof ViewHolder)) {
viewHolder = new ViewHolder();
viewHolder.titleView = (TextView) workingView.findViewById(R.id.title);
viewHolder.subTitleView = (TextView) workingView.findViewById(R.id.description);
//viewHolder.imageView = (ImageView) workingView.findViewById(R.id.news_entry_icon);
workingView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) tag;
}
return viewHolder;
}
/**
* ViewHolder allows us to avoid re-looking up view references
* Since views are recycled, these references will never change
*/
private static class ViewHolder {
public TextView titleView;
public TextView subTitleView;
//public ImageView imageView;
}
}
ShopActivity.java
public class ShopActivity extends AppCompatActivity {
ListView shopList;
CustomListAdapter adapter;
private ArrayList<shopClass> shopObjects;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_shop);
shopList = (ListView) findViewById(R.id.list);
ShopData start = new ShopData();
shopObjects = start.getShopData();
adapter = new CustomListAdapter(this, shopObjects, R.layout.list_row);
for (int i = 0; i<2; i++){
System.out.println(shopObjects.get(i).toString());
adapter.add(shopObjects.get(i));
}
shopList.setAdapter(adapter);
}
Activity_shop.xml
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.csthack.beinnovative.destination_brooklyn.ShopActivity"
tools:showIn="@layout/activity_shop">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="match_parent">
<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:divider="@color/list_divider"
android:dividerHeight="1dp"
android:listSelector="@drawable/list_row_selector" />
</LinearLayout>
</LinearLayout>
listrow.xml
<?xml version="1.0" encoding="utf-8"?>
<!--Style for the list-->
<android.support.percent.PercentRelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior" >
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/list_row_selector"
app:layout_heightPercent="33%"
app:layout_widthPercent="100%">
<!-- Background Image -->
<LinearLayout
android:id="@+id/bkgImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/coffe"
android:orientation="vertical"
android:alpha="0.65"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_gravity="bottom|start"
android:layout_alignParentBottom="true"
android:paddingLeft="10dp">
<!-- Shop Title -->
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Test"
android:textSize="@dimen/title"
android:textStyle="bold"
android:textColor="@color/genre"
android:alpha="1.0"/>
<!-- Description -->
<TextView
android:id="@+id/description"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/title"
android:layout_marginTop="5dp"
android:layout_marginBottom="10dp"
android:text="blah blah blahg blah blah blah "
android:textColor="@color/genre"
android:textSize="@dimen/genre" />
</LinearLayout>
</RelativeLayout>
</android.support.percent.PercentRelativeLayout>
我看了其他教程，但他們似乎都圍繞着同樣的邏輯工作，並嘗試3但仍然沒有內容。
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我建議你打印一些日誌，看看調用了多少次'getView'，並且每次'getView'被調用是否'shopClass shop = getItem（position）;'返回一個正確的商店實例。 – shhp
@shhp現在它崩潰，我不知道爲什麼。 – baldemora
看來'shopList =（ListView）findViewById（R.id.list）;'返回一個空對象。你確定這裏的'R'是你的包而不是android嗎？ – shhp