如何創建自定義基礎適配器？

Question

我試圖讓我自己的基礎適配器動態顯示ListFragment中的RadioButtons，代碼崩潰，我不知道究竟是什麼原因，但是當我嘗試在ListView上設置適配器時，會發生這種情況。知道我做錯了什麼？

的XML單選按鈕：

<?xml version="1.0" encoding="utf-8"?> 
<RadioButton xmlns:android="http://schemas.android.com/apk/res/android" 
android:id="@+id/rbTipo" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content" 
/> 

ListView的XML：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 
    <ListView 
     android:id="@android:id/list" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content"> 
    </ListView> 
</RelativeLayout> 

適配器的類別：

public class TipoAdapter extends BaseAdapter { 
private ArrayList<Tipo> tipos; 
private Context context; 
public TipoAdapter(Context context,ArrayList<Tipo> tipos) { 
    this.tipos = tipos; 
    this.context = context; 
} 

@Override 
public int getCount() { 
    return tipos.size(); 
} 

@Override 
public Tipo getItem(int i) { 
    return tipos.get(i); 
} 

@Override 
public long getItemId(int i) { 
    return i; 
} 

@Override 
public View getView(int i, View view, ViewGroup viewGroup) { 
    ViewHolder holder; 
    if(view == null){ 
     view= LayoutInflater.from(context).inflate(R.layout.item_tipo_trilha,viewGroup,false); 
     holder= new ViewHolder(); 
     holder.rb=(RadioButton) view.findViewById(R.id.rbTipo); 
     view.setTag(holder); 

    }else{ 
     holder=(ViewHolder)view.getTag(); 
    } 
    Tipo b = getItem(i); 
    holder.rb.setText(b.tipNome); 
    holder.rb.setTag(i); 

    return view; 

} 
private static class ViewHolder{ 
    RadioButton rb; 
    public ViewHolder() { 
    } 
} 

的ListFragment類別：

public class TiposFragment extends ListFragment { 
private ArrayList<Tipo> tipos; 
private TipoAdapter tipoAdapter; 
private int selecionado; 
private ListView listView; 

@Override 
public void onActivityCreated(Bundle savedInstanceState) { 
    super.onActivityCreated(savedInstanceState); 


} 

@Override 
public void onListItemClick(ListView lv, View v, int position, long id) { 
    super.onListItemClick(lv, v, position, id); 
    selecionado = tipoAdapter.getItem(position).tipCod; 
    for(int i=0;i<lv.getCount();i++){ 
     if(i!=position){ 
     RadioButton rb= (RadioButton) lv.getChildAt(i); 
      rb.setChecked(false); 
     } 
    } 
    Toast.makeText(getContext(), lv.getChildAt(position).toString(), Toast.LENGTH_SHORT).show(); 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.fragment_tipo_trilha, container, false); 
    listView=(ListView) view.findViewById(android.R.id.list); 
    try { 
     Bundle bundle = getArguments(); 
     if (bundle != null) { 
      tipos = bundle.getParcelableArrayList("tipos"); 
     } 


    } catch (Exception e) { 
     Toast.makeText(getContext(), e.toString(), Toast.LENGTH_LONG).show(); 
    } 

    if (tipos != null) { 
     try { 
      tipoAdapter = new TipoAdapter(getContext(), tipos); 
      listView.setAdapter(tipoAdapter); 
      setListAdapter(tipoAdapter); 

      // Toast.makeText(getContext(),String.valueOf(listaTipos.getCount()),Toast.LENGTH_LONG).show(); 

     } catch (Exception e) { 
      // Toast.makeText(getContext(), e.toString(), Toast.LENGTH_LONG).show(); 
      Log.d("TAG",e.toString()); 
      Toast.makeText(getContext(),e.toString(),Toast.LENGTH_LONG).show(); 
     } 

    } 
    return view; 
} 

的logcat的堆棧跟蹤：

05-09 10:23:03.309 909-909/bdes.dcc.joinville.udesc.br.biketrilhas E/AndroidRuntime: FATAL EXCEPTION: main 
                       Process: bdes.dcc.joinville.udesc.br.biketrilhas, PID: 909 
                       java.lang.ClassCastException: java.lang.Integer cannot be cast to br.udesc.joinville.dcc.bdes.adapter.TipoAdapter$ViewHolder 
                        at br.udesc.joinville.dcc.bdes.adapter.TipoAdapter.getView(TipoAdapter.java:52) 
                        at android.widget.AbsListView.obtainView(AbsListView.java:2396) 
                        at android.widget.ListView.measureHeightOfChildren(ListView.java:1290) 
                        at android.widget.ListView.onMeasure(ListView.java:1202) 
                        at android.view.View.measure(View.java:17834) 
                        at android.widget.RelativeLayout.measureChild(RelativeLayout.java:698) 
                        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:482) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5725) 
                        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5725) 
                        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
                        at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
                        at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5725) 
                        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
                        at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5725) 
                        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
                        at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
                        at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5725) 
                        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5725) 
                        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
                        at android.widget.LinearLayout.measureVertical(LinearLayout.java:722) 
                        at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5725) 
                        at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) 
                        at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2848) 
                        at android.view.View.measure(View.java:17834) 
                        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2030) 
                        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1174) 
                        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1395) 
                        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1062) 
                        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5873) 
                        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767) 
                        at android.view.Choreographer.doCallbacks(Choreographer.java:580) 
                        at android.view.Choreographer.doFrame(Choreographer.java:550) 
                        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753) 
                        at android.os.Handler.handleCallback(Handler.java:739) 
                        at android.os.Handler.dispatchMessage(Handler.java:95) 
                        at android.os.Looper.loop(Looper.java:135) 
                        at android.app.ActivityThread.main(ActivityThread.java:5753) 
                        at java.lang.reflect.Method.invoke(Native Method) 
                        at java.lang.reflect.Method.invoke(Method.java:372) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200) 

Answer 1

不兼容類型的適配器會導致死機。這包括，例如，試圖在適配器輸出的TextView中顯示一個數字，而不是使用「Integer.toString（i）;」正確投射它。

Answer 2

1.在TiposFragment.java中，將所有getContext()替換爲getActivity()。

2.下面線從onCreateView()刪除：如下面

listView = (ListView) view.findViewById(android.R.id.list); 
listView.setAdapter(tipoAdapter); 

更新TiposFragment：

public class TiposFragment extends ListFragment { 
private ArrayList<Tipo> tipos; 
private TipoAdapter tipoAdapter; 
private int selecionado; 

@Override 
public void onActivityCreated(Bundle savedInstanceState) { 
    super.onActivityCreated(savedInstanceState); 

} 

@Override 
public void onListItemClick(ListView lv, View v, int position, long id) { 
    super.onListItemClick(lv, v, position, id); 
    selecionado = tipoAdapter.getItem(position).tipCod; 
    for(int i=0;i<lv.getCount();i++){ 
     if(i!=position){ 
     RadioButton rb= (RadioButton) lv.getChildAt(i); 
      rb.setChecked(false); 
     } 
    } 
    Toast.makeText(getActivity(), lv.getChildAt(position).toString(), Toast.LENGTH_SHORT).show(); 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.fragment_tipo_trilha, container, false); 

    try { 
     Bundle bundle = getArguments(); 
     if (bundle != null) { 
      tipos = bundle.getParcelableArrayList("tipos"); 
     }  
    } catch (Exception e) { 
     Toast.makeText(getActivity(), e.toString(), Toast.LENGTH_LONG).show(); 
    } 

    if (tipos != null) { 
     try { 
      tipoAdapter = new TipoAdapter(getActivity(), tipos); 
      setListAdapter(tipoAdapter); 

     } catch (Exception e) { 

      Log.d("TAG",e.toString()); 
      Toast.makeText(getActivity(), e.toString(),Toast.LENGTH_LONG).show(); 
     } 

    } 
    return view; 
} 

這裏是一個很好tutorial。

希望這會有所幫助〜