Android圖片庫和片段問題

Question

我試圖在我的應用中使用fragment實現this圖庫。 我能夠適應的代碼爲我的需要，但我得到了NullPointerException但我不能想通了，爲什麼...

的問題是完全一樣this之一，但用戶解決它，而無需繳納任何相關信息這個問題，因此我開了這個問題....

這是我的代碼：

GalleriaPersonaggio.java

import java.util.ArrayList; 

import android.app.Fragment; 
import android.content.res.TypedArray; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.os.Bundle; 
import android.view.InflateException; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.GridView; 

import com.italiandevteam.chuck.adapter.GridViewAdapter; 
import com.italiandevteam.chuck.model.ImageItem; 

public class GalleriaPersonaggio extends Fragment{ 

Integer personaggio = null; 


    public GalleriaPersonaggio(int personaggio){ 

     this.personaggio = personaggio; 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 

     int id = getIdPersonaggio(); 

     View rootView = null; 

     if (rootView != null) { 
      ViewGroup parent = (ViewGroup) rootView.getParent(); 
      if (parent != null) 
       parent.removeView(rootView); 
     } 
     try { 
      rootView = inflater.inflate(R.layout.gallery_grid, container, false); 
     } catch (InflateException e) { 
     } 

     GridView gridView = (GridView) getView().findViewById(R.id.gridView); 
     GridViewAdapter customGridAdapter = new GridViewAdapter(getActivity(), R.layout.gallery_row, getData(personaggio)); 
     gridView.setAdapter(customGridAdapter); 

     return rootView; 
    } 

    public int getIdPersonaggio(){ 
     return this.personaggio; 
    } 

    private ArrayList getData(int personaggio) { 
     final ArrayList imageItems = new ArrayList(); 
     // retrieve String drawable array 
     TypedArray imgs = getResources().obtainTypedArray(R.array.chuck_ids); 
     for (int i = 0; i < imgs.length(); i++) { 
      Bitmap bitmap = BitmapFactory.decodeResource(this.getResources(), 
        imgs.getResourceId(i, -1)); 
      imageItems.add(new ImageItem(bitmap, "Image#" + i)); 
     } 

     return imageItems; 

    } 
} 

這是我GridViewAdapter.java

import java.util.ArrayList; 

    import android.app.Activity; 
    import android.content.Context; 
    import android.view.LayoutInflater; 
    import android.view.View; 
    import android.view.ViewGroup; 
    import android.widget.ArrayAdapter; 
    import android.widget.ImageView; 
    import android.widget.TextView; 

    import com.italiandevteam.chuck.R; 
    import com.italiandevteam.chuck.model.ImageItem; 


    public class GridViewAdapter extends ArrayAdapter<ImageItem> { 
     private Context context; 
     private int layoutResourceId; 
     private ArrayList<ImageItem> data = new ArrayList<ImageItem>(); 

     public GridViewAdapter(Context context, int layoutResourceId, 
         ArrayList<ImageItem> data) { 
       super(context, layoutResourceId, data); 
       this.layoutResourceId = layoutResourceId; 
       this.context = context; 
       this.data = data; 
     } 

     @Override 
     public View getView(int position, View convertView, ViewGroup parent) { 
       View row = convertView; 
       ViewHolder holder = null; 

       if (row == null) { 
         LayoutInflater inflater = ((Activity) context).getLayoutInflater(); 
         row = inflater.inflate(layoutResourceId, parent, false); 
         holder = new ViewHolder(); 
         holder.imageTitle = (TextView) row.findViewById(R.id.text); 
         holder.image = (ImageView) row.findViewById(R.id.image); 
         row.setTag(holder); 
       } else { 
         holder = (ViewHolder) row.getTag(); 
       } 

       ImageItem item = data.get(position); 
       holder.imageTitle.setText(item.getTitle()); 
       holder.image.setImageBitmap(item.getImage()); 
       return row; 
     } 

     static class ViewHolder { 
       TextView imageTitle; 
       ImageView image; 
     } 
    } 

and this is my ImageItem.java 


import android.graphics.Bitmap; 


public class ImageItem { 
    private Bitmap image; 
    private String title; 

    public ImageItem(Bitmap image, String title) { 
     super(); 
     this.image = image; 
     this.title = title; 
    } 

    public Bitmap getImage() { 
     return image; 
    } 

    public void setImage(Bitmap image) { 
     this.image = image; 
    } 

    public String getTitle() { 
     return title; 
    } 

    public void setTitle(String title) { 
     this.title = title; 
    } 
} 

而這正是logcat的：

12-11 15:03:30.262: E/AndroidRuntime(19554): FATAL EXCEPTION: main 
12-11 15:03:30.262: E/AndroidRuntime(19554): java.lang.NullPointerException 
12-11 15:03:30.262: E/AndroidRuntime(19554): at com.italiandevteam.chuck.GalleriaPersonaggio.onCreateView(GalleriaPersonaggio.java:46) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.app.Fragment.performCreateView(Fragment.java:1695) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:885) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1057) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.app.BackStackRecord.run(BackStackRecord.java:682) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1435) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.app.FragmentManagerImpl$1.run(FragmentManager.java:441) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.os.Handler.handleCallback(Handler.java:730) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.os.Handler.dispatchMessage(Handler.java:92) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.os.Looper.loop(Looper.java:137) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at android.app.ActivityThread.main(ActivityThread.java:5103) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at java.lang.reflect.Method.invokeNative(Native Method) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at java.lang.reflect.Method.invoke(Method.java:525) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
12-11 15:03:30.262: E/AndroidRuntime(19554): at dalvik.system.NativeStart.main(Native Method) 

線46是：

GridView gridView = (GridView) getView().findViewById(R.id.gridView); 

Answer 1

更改此

GridView gridView = (GridView) getView().findViewById(R.id.gridView); 

到

GridView gridView = (GridView)rootView.findViewById(R.id.gridView); 

您需要使用充氣視圖對象初始化你的GridView

View rootView = rootView = inflater.inflate(R.layout.gallery_grid, container, false); 
GridView gridView = (GridView) rootView.findViewById(R.id.gridView); 
GridViewAdapter customGridAdapter = new GridViewAdapter(getActivity(), R.layout.gallery_row, getData(personaggio)); 
gridView.setAdapter(customGridAdapter);