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NullPointerException同時膨脹dragSortListView

2014-11-05 70 views
0

您好我試圖從服務器中加載圖像dragSortListView使用bauerca library實現。我有一個簡單的佈局，使用imageview作爲拖拽手柄。我寫了下面的代碼NullPointerException同時膨脹dragSortListView

import java.util.ArrayList; 
import android.app.Activity; 
import android.content.Context; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.BaseAdapter; 
import android.widget.ImageView; 
import android.widget.TextView; 

import com.mobeta.android.dslv.DragSortController; 
import com.mobeta.android.dslv.DragSortListView; 
import com.squareup.picasso.Picasso; 

public class MainActivity extends Activity { 
DragSortListView listView; 
ReorderAdapter adapter; 

private DragSortListView.DropListener onDrop = new DragSortListView.DropListener() 
{ 
    @Override 
    public void drop(int from, int to) 
    { 
     if (from != to) 
     { 
      Model item = (Model) adapter.getItem(from); 
      adapter.list.remove(from); 
      adapter.list.add(to, item); 
     } 
    } 
}; 

private DragSortListView.RemoveListener onRemove = new DragSortListView.RemoveListener() 
{ 
    @Override 
    public void remove(int which) 
    { 
     adapter.list.remove(which); 
    } 
}; 

@Override 
protected void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    listView = (DragSortListView) findViewById(R.id.listview); 
    String[] names = new String[]{"http://url1", 
      "http://url2","http://url3", "http://url4"}; 

    ArrayList<Model> list = new ArrayList<Model>(); 
    for (int i=0; i<names.length; i++) { 
     list.add(new Model(names[i], names[i], i)); 
    } 
    adapter = new ReorderAdapter(this, R.layout.item_layout, list); 
    listView.setAdapter(adapter); 
    listView.setDropListener(onDrop); 
    listView.setRemoveListener(onRemove); 

    DragSortController controller = new DragSortController(listView); 
    controller.setDragHandleId(R.id.menu); 
      //controller.setClickRemoveId(R.id.); 
    controller.setRemoveEnabled(false); 
    controller.setSortEnabled(true); 
    controller.setDragInitMode(1); 
      //controller.setRemoveMode(removeMode); 

    listView.setFloatViewManager(controller); 
    listView.setOnTouchListener(controller); 
    listView.setDragEnabled(true); 
} 

private class Model { 
    private String text; 
    private String url; 
    private int position; 

    public Model (String text, String url, int position) { 
     this.text = text; 
     this.url = url; 
     this.position = position; 
    } 

    @Override 
    public boolean equals(Object o) { 
     if (((Model)o).position == this.position) 
      return true; 
     return false; 
    } 
} 
protected DragSortListView getListView() { 
    // TODO Auto-generated method stub 
    return (DragSortListView) this.findViewById(R.id.listview); 
} 
private class ReorderAdapter extends BaseAdapter { 
    private ArrayList<Model> list; 
    Context context; 

    public ReorderAdapter(Context context, int resource, ArrayList<Model> objects) { 
     this.list = objects; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     View v = convertView; 

     if (v == null) { 
      LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      v = vi.inflate(R.layout.item_layout, parent, false); 
     } 

     ((TextView)v.findViewById(R.id.textView)).setText(list.get(position).text); 
     String photo_source=list.get(position).url.toString().replaceAll(" ", "%20"); 
     try { 
      Picasso.with(context).load(photo_source) 
      .placeholder(R.drawable.ic_launcher) 
      .error(R.drawable.ic_launcher) 
      .into(((ImageView)v.findViewById(R.id.menu))); 
     } catch(IllegalArgumentException illegalArg){ 
      illegalArg.printStackTrace(); 
     } catch(Exception e){ 
      e.printStackTrace(); 
     } 
     return v; 
    } 

    @Override 
    public int getCount() { 
     // TODO Auto-generated method stub 
     return list.size(); 
    } 

    @Override 
    public Object getItem(int position) { 
     // TODO Auto-generated method stub 
     return list.get(position); 
    } 

    @Override 
    public long getItemId(int position) { 
     // TODO Auto-generated method stub 
     return position; 
    } 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) 
{ 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.main, menu); 
    return true; 
} 
}

，但我一直在該行獲得NullPointerException當我試圖讓LayoutInflater在getView()方法。

下面是異常的堆棧跟蹤。

11-05 10:20:21.801: E/AndroidRuntime(10513): java.lang.NullPointerException 
11-05 10:20:21.801: E/AndroidRuntime(10513): at com.example.dndlist.MainActivity$ReorderAdapter.getView(MainActivity.java:120) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at com.mobeta.android.dslv.DragSortListView$AdapterWrapper.getView(DragSortListView.java:730) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.AbsListView.obtainView(AbsListView.java:2207) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.ListView.makeAndAddView(ListView.java:1845) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.ListView.fillDown(ListView.java:678) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.ListView.fillFromTop(ListView.java:739) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.ListView.layoutChildren(ListView.java:1661) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at com.mobeta.android.dslv.DragSortListView.layoutChildren(DragSortListView.java:2136) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.AbsListView.onLayout(AbsListView.java:2037) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.View.layout(View.java:14094) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewGroup.layout(ViewGroup.java:4464) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:985) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.View.layout(View.java:14094) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewGroup.layout(ViewGroup.java:4464) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.FrameLayout.onLayout(FrameLayout.java:448) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.View.layout(View.java:14094) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewGroup.layout(ViewGroup.java:4464) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1670) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1528) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.LinearLayout.onLayout(LinearLayout.java:1441) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.View.layout(View.java:14094) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewGroup.layout(ViewGroup.java:4464) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.widget.FrameLayout.onLayout(FrameLayout.java:448) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.View.layout(View.java:14094) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewGroup.layout(ViewGroup.java:4464) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2183) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1947) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1139) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4879) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:776) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.Choreographer.doCallbacks(Choreographer.java:579) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.Choreographer.doFrame(Choreographer.java:548) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:762) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.os.Handler.handleCallback(Handler.java:725) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.os.Handler.dispatchMessage(Handler.java:92) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.os.Looper.loop(Looper.java:153) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at android.app.ActivityThread.main(ActivityThread.java:5297) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at java.lang.reflect.Method.invokeNative(Native Method) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at java.lang.reflect.Method.invoke(Method.java:511) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600) 
11-05 10:20:21.801: E/AndroidRuntime(10513): at dalvik.system.NativeStart.main(Native Method)

來源

2014-11-05 Roadblock

+0

它總是關於** ** NPE笑 – Elltz 2014-11-05 05:07:58

回答

1

改變這個代碼，

private class ReorderAdapter extends BaseAdapter { 
    private ArrayList<Model> list; 
    Context context; 

    public ReorderAdapter(Context context, int resource, ArrayList<Model> objects) { 
     this.list = objects; 
     this.context = context; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     View v = convertView; 

     if (v == null) { 
      LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      v = vi.inflate(R.layout.item_layout, parent, false); 
     } 

     ((TextView)v.findViewById(R.id.textView)).setText(list.get(position).text); 
     String photo_source=list.get(position).url.toString().replaceAll(" ", "%20"); 
     try { 
      Picasso.with(context).load(photo_source) 
      .placeholder(R.drawable.ic_launcher) 
      .error(R.drawable.ic_launcher) 
      .into(((ImageView)v.findViewById(R.id.menu))); 
     } catch(IllegalArgumentException illegalArg){ 
      illegalArg.printStackTrace(); 
     } catch(Exception e){ 
      e.printStackTrace(); 
     } 
     return v; 
    } 

    @Override 
    public int getCount() { 
     // TODO Auto-generated method stub 
     return list.size(); 
    } 

    @Override 
    public Object getItem(int position) { 
     // TODO Auto-generated method stub 
     return list.get(position); 
    } 

    @Override 
    public long getItemId(int position) { 
     // TODO Auto-generated method stub 
     return position; 
    } 
}

來源

2014-11-05 05:01:36

0

試試這個辦法，希望這將幫助你解決你的問題。

的第一件事是NPE來到因您不能初始化上下文對象，它是您使用畢加索這樣初始化上下文對象在構造函數中使用膨脹佈局，以及負荷的形象：

this.context= context;

第二件事是每當你使用自定義適配器始終嘗試使用ViewHolder模式。

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
    Viewholder holder; 
    if (convertView == null) { 
     holder = new Viewholder(); 
     convertView = LayoutInflater.from(context).inflate(R.layout.item_layout, null); 
     holder.textView = (TextView) convertView.findViewById(R.id.textView); 
     holder.menu = (TextView) convertView.findViewById(R.id.menu); 

     convertView.setTag(holder); 
    }else{ 
     holder =(Viewholder) convertView.getTag(); 
    } 


    holder.textView.setText(list.get(position).text); 
    try { 
      Picasso.with(context).load(list.get(position).url.toString().replaceAll(" ", "%20")).placeholder(R.drawable.ic_launcher).error(R.drawable.ic_launcher).into(holder.menu); 
    } catch(IllegalArgumentException illegalArg){ 
     illegalArg.printStackTrace(); 
    } catch(Exception e){ 
     e.printStackTrace(); 
    } 
    return convertView; 
} 

class Viewholder { 
    TextView textView; 
    ImageView menu; 
}

來源

2014-11-05 05:33:26

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