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請看看，我有一個片段，設置一個適配器，從Firebase數據庫中獲取字符串url值，但沒有圖像加載。firebase加載圖像在listview中使用picasso
我的片段：
public class PromoFragment extends Fragment {
private DatabaseReference mDatabase;
List<Promo> promoList = new ArrayList<>();
ListView listViewPromo;
public PromoFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDatabase = FirebaseDatabase.getInstance().getReference();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_promo, container, false);
listViewPromo = (ListView) view.findViewById(R.id.listViewPromo);
listenPromo(); //here i load my data, i currently have 3 childs, each child has imageUrl
PromoAdapter promoAdapter = new PromoAdapter(getActivity().getApplicationContext(), R.layout.list_promo, promoList);
listViewPromo.setAdapter(promoAdapter);
return view;
}
private void listenPromo() {
mDatabase.child("Promo").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
// Get Post object and use the values to update the UI
// MainActivity.currUser = dataSnapshot.getValue(User.class);
for (DataSnapshot dsp : dataSnapshot.getChildren()) {
promoList.add(dsp.getValue(Promo.class)); //add result into array list
}
// ...
}
@Override
public void onCancelled(DatabaseError databaseError) {
// Getting User Class data failed...
Log.w("Canceled", "loadUserData:onCancelled", databaseError.toException());
// ...
}
});
}
}
我fragment_promo.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".PromoFragment">
<ListView
android:id="@+id/listViewPromo"
android:layout_height="wrap_content"
android:layout_width="match_parent">
</ListView>
</RelativeLayout>
list_promo.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">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/imageViewPromo" />
</LinearLayout>
promo.java類
我有3個變量爲每個對象，但我只會使用durl（網址下載）爲這種情況。
public class Promo {
private String durl;
private Boolean active;
private String timestamp;
public Promo() { //default constructor
}
public Promo(String durl, Boolean active, String timestamp) {
this.durl = durl;
this.active = active;
this.timestamp = timestamp;
}
public String getDurl() {
return durl;
}
public void setDurl(String durl) {
this.durl = durl;
}
public Boolean getActive() {
return active;
}
public void setActive(Boolean active) {
this.active = active;
}
public String getTimestamp() {
return timestamp;
}
public void setTimestamp(String timestamp) {
this.timestamp = timestamp;
}
}
PromoAdapter.java類
public class PromoAdapter extends ArrayAdapter<Promo> {
Context context;
List<Promo> myList;
public PromoAdapter(Context context, int resource, List<Promo> objects) {
super(context, resource, objects);
this.context = context;
this.myList = objects;
}
@Override
public int getCount() {
if(myList != null)
return myList.size();
return 0;
}
@Override
public Promo getItem(int position) {
if(myList != null)
return myList.get(position);
return null;
}
@Override
public long getItemId(int position) {
if(myList != null)
return myList.get(position).hashCode();
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Holder holder;
if (convertView == null){
//we need a new holder to hold the structure of the cell
holder = new Holder();
//get the XML inflation service
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.list_promo, null);
holder.imageView = (ImageView)convertView.findViewById(R.id.imageViewPromo);
convertView.setTag(holder);
}else{
holder = (Holder)convertView.getTag();
}
Promo promo = getItem(position);
Picasso.with(context)
.load(promo.getDurl())
.placeholder(R.drawable.coin25)
.error(R.drawable.hnbspic)
.into(holder.imageView);
return convertView;
}
private class Holder{
ImageView imageView;
}
我曾嘗試：
檢查瀏覽器中的圖像網址有效
的listenPr大面也讓所有與IMAGEURL孩子成功（我測試過它之前使用之前畢加索得到數據庫中的數據）
變化
load(promo.getDurl())到load(uri.parse(promo.getDurl()))添加佔位符和錯誤的形象，也沒有圖像出現。我的片段是空白的。
請幫忙..如果代碼工作，那麼它應該顯示3張圖片。
感謝您的任何關注。
問題是刷新適配器，它先設置適配器，然後得到圖像url.just通知適配器後，在onDataChange – 9spl
得到sussess響應imageurl應該在數組之前，我將它設置爲適配器。 –
addValueEventListener在後臺工作，因此代碼將其設置在背景中並首先移動到setAdapter。你可以顯示完整的代碼，你用Piccaso設置圖像。 – 9spl