Android：如何使用View的setTag,getTag和findViewWithTag方法？

我的 Android应用程序的代码段有一些麻烦.尝试设置ImageView对象的背景时,我会继续收到NullPointerException.

以下是代码：

public View getView(int position,View view,ViewGroup parent) {
    ImageView imageView;
    if (view == null) {
        imageView = new ImageView(mContext);
    } else {
        imageView = (ImageView) view;
    }
    imageView.setTag(position);
    return imageView;
}

private OnItemClickListener itemClickListener = new OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent,View v,int position,long id) {

        ImageView imageView;
        //Variable i,here,is from a for loop.
        imageView = (ImageView)v.findViewWithTag(i);
        //I get a NullPointerException at the next line,"Log.d"
        Log.d("View 1",imageView.toString());
        //If I get rid of the "Log.d" line above,//the NullPointerException occurs on the next line
        imageView.setBACkgroundColor(Color.bLUE);
        imageView = (ImageView)v.findViewWithTag(position);

        Log.d("View 2",imageView.toString());
        imageView.setBACkgroundColor(Color.bLUE);

    };
}

我怀疑我的代码的问题是因为我传递了setTag()方法的什么参数以及我传递findViewWithTag()方法的参数.如果有人可以向我展示如何使用标签设置标签和查看视图的示例,我将非常感谢.

感谢您的时间.

编辑：这是错误日志.我不知道该放在哪里,所以我会把它放在这里.

05-04 21:47:24.314: ERROR/AndroidRuntime(335): FATAL EXCEPTION: main
05-04 21:47:24.314: ERROR/AndroidRuntime(335): java.lang.NullPointerException
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at com.jacksmartie.PhotoMem.MainActivity$1.onItemClick(MainActivity.java:79)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at android.widget.AdapterView.performItemClick(AdapterView.java:284)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at android.widget.AbsListView$PerformClick.run(AbsListView.java:1696)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at android.os.Handler.handleCallBACk(Handler.java:587)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at android.os.Handler.dispatchmessage(Handler.java:92)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at android.os.Looper.loop(Looper.java:123)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at java.lang.reflect.Method.invokeNative(Native Method)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at java.lang.reflect.Method.invoke(Method.java:521)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-04 21:47:24.314: ERROR/AndroidRuntime(335):     at dalvik.system.NativeStart.main(Native Method)`

com.jacksmartie.PhotoMem.MainActivity$1.onItemClick(MainActivity.java:79)

Log.d("View 1",imageView.toString());

Button b = findViewById(R.id.button01);