安卓是不是我错了?未捕获的异常 (组 = 0x4001d800)

Question

这项工作基于Patel Deval的例子。

应用程序打算根据选定的单选按钮加载图像搜索内容。在运行时，将打印未捕获的异常 （group=0x4001d800）。我错在哪里？这是代码

private Gallery gallery;
private RadioGroup rdgSelection;
private ImageSwitcher isSwitcher;
private Boolean flag = true;
private int radioCheckedId = -1; //no radio button
//arrays of image for alerts
private Integer[] pics ={ R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d,R.drawable.e,R.drawable.exit, R.drawable.plan, R.drawable.icon, R.drawable.plan };
private Integer[] others = {R.drawable.exit, R.drawable.plan, R.drawable.icon, R.drawable.plan,R.drawable.c };

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.sendalert);
    gallery = (Gallery)findViewById(R.id.imgGallery);
    isSwitcher = (ImageSwitcher)findViewById(R.id.ImgSwith);
    rdgSelection = (RadioGroup)findViewById(R.id.radEvent);

    isSwitcher = setFactory(this);
    //get radio button id
    rdgSelection.check(rdgSelection.getChildAt(rdgSelection.getChildCount() - 1).getId());
    if (rdgSelection.getCheckedRadioButtonId()==R.id.radBtnAccident){
        flag = true;

                    gallery.setAdapter(new ImageAdapter(MsgToWeb.this));
    }else{
        flag=false;
        gallery.setAdapter(new ImageAdapter(MsgToWeb.this));
    }
     rdgSelection.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            public void onCheckedChanged(RadioGroup group, int checkedId) {
                gallery.setAdapter(new ImageAdapter(MsgToWeb.this));
                if (rdgSelection.getCheckedRadioButtonId() == R.id.radBtnAccident)
                    flag = true;
                else
                    flag = false;
            }
        });
        gallery.setOnItemSelectedListener(this);
}

private ImageSwitcher setFactory(MsgToWeb msgToWeb) {
    // TODO Auto-generated method stub
    return null;
}

public class ImageAdapter extends BaseAdapter {
    private Context mContext;
    public ImageAdapter(Context c) {
        mContext = c; 
    }
    public Object getItemId() {
        // TODO Auto-generated method stub
        return null;
    }
    public int getCount() {
        //return num of arrays
        if (flag)
            return pics.length;
        else
            return others.length;
    }
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position;
    }
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView i = new ImageView(mContext);
        if(flag)
            i.setImageResource(pics[position]);
        else
            i.setImageResource(others[position]);
        return i;   
    }
}
public View makeView() {
    // TODO Auto-generated method stub
    ImageView iView = new ImageView(this);
    iView.setBackgroundColor(0xFF000000);
    iView.setScaleType(ImageView.ScaleType.FIT_CENTER);
    iView.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT));
    return iView;
}

public void onItemSelected(AdapterView<?> arg0, View v, int position,long id) {
    // TODO Auto-generated method stub

    if(flag)
        isSwitcher.setImageResource(pics[position]);
    else
        isSwitcher.setImageResource(others[position]);

}

public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub
}

}

这里是日志

05-24 10:07:03.394: W/dalvikvm(321): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
05-24 10:07:03.404: E/AndroidRuntime(321): FATAL EXCEPTION: main
05-24 10:07:03.404: E/AndroidRuntime(321): java.lang.NullPointerException
05-24 10:07:03.404: E/AndroidRuntime(321):  at com.moLaroute.mu.MsgToWeb.onItemSelected(MsgToWeb.java:147)
05-24 10:07:03.404: E/AndroidRuntime(321):  at android.widget.AdapterView.fireOnSelected(AdapterView.java:864)
05-24 10:07:03.404: E/AndroidRuntime(321):  at android.widget.AdapterView.access$200(AdapterView.java:42)
05-24 10:07:03.404: E/AndroidRuntime(321):  at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:830)
05-24 10:07:03.404: E/AndroidRuntime(321):  at android.os.Handler.handleCallback(Handler.java:587)
05-24 10:07:03.404: E/AndroidRuntime(321):  at android.os.Handler.dispatchMessage(Handler.java:92)
05-24 10:07:03.404: E/AndroidRuntime(321):  at android.os.Looper.loop(Looper.java:123)
05-24 10:07:03.404: E/AndroidRuntime(321):  at android.app.ActivityThread.main(ActivityThread.java:4627)
05-24 10:07:03.404: E/AndroidRuntime(321):  at java.lang.reflect.Method.invokeNative(Native Method)
05-24 10:07:03.404: E/AndroidRuntime(321):  at java.lang.reflect.Method.invoke(Method.java:521)
05-24 10:07:03.404: E/AndroidRuntime(321):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-24 10:07:03.404: E/AndroidRuntime(321):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-24 10:07:03.404: E/AndroidRuntime(321):  at dalvik.system.NativeStart.main(Native Method)
05-24 10:07:07.014: I/Process(321): Sending signal. PID: 321 SIG: 9

Answer 1

isSwitcher = setFactory（this）;

->

setFactory 返回空

值

->

如果（标志） isSwitcher.setImageResource（pics[position]）; 还 isSwitcher.setImageResource（others[position]）;

在这里抛出 NPE，因为 isSwitcher 为空