Java 新的可重用对话框片段

我正在尝试一个带有真正可重用代码的新对话框。 但是我在dialogOnClick&Click上得到一个Nullpointer异常错误 以下是日志：

YNNfragmentDialog.java java testCodeFragment.java DialogConstants.java activity_dialog.xml

---

成功后，我将发布对话框的整个解决方案。

添加以下代码将生成错误：添加以下代码将生成错误：
\u ClassCastException\u
`@Override public void onAttach（Activity活动）{super.onAttach（Activity）；if（DEF_DEBUG）Log.d（Log，“class=”+getTargetFragment（）.getClass（）；尝试{mTarget=（YNNinterface）活动；}catch（ClassCastException e）{抛出新的ClassCastException（activity.toString（）+“实现YNNinterface侦听器（mTarget）”；}`

package at.bomsbg;

import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnCancelListener;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.FragmentManager;
import android.util.Log;
import at.bomsbg.MindX.MindXconstants;

/**
 * @author asteidl
 *
 */
public final class YNNfragmentDialog extends DialogFragment implements DialogConstants, MindXconstants{
    private final String LOG = this.getClass().getSimpleName();
    private static final String EXTRA_CHOOSE = "CHOOSE";
    static private int mRequest_tag;
    private static String mTitle;
    private static String mMessage;
    private Drawable mImage;
    private static boolean mCancelable;
    private static YNNinterface mTarget;

    public static final String TAG = YNNfragmentDialog.class.getSimpleName();

    public static YNNfragmentDialog newInstance(Context tobjContext, 
            int tintrequest_tag, 
            String tstrTitle, 
            String tstrMessage, 
            Boolean tbolCancelable, 
            YNNinterface tobjTarget) {
        mRequest_tag = tintrequest_tag;
        mTitle = tstrTitle;
        mMessage = tstrMessage;
        mCancelable = tbolCancelable;
        mTarget = tobjTarget;

        Bundle args = new Bundle();
//        args.putSerializable(EXTRA_CHOOSE, "YesNo");
//        args.putSerializable(TAG, "hallo");
        YNNfragmentDialog fragment = new YNNfragmentDialog();
        fragment.setArguments(args);
        return fragment;
    }

    public YNNfragmentDialog(Context tobjContext, 
                final int tintrequest_tag, 
                String tstrTitle, 
                String tstrMessage, 
                boolean tbolCancelable, 
                final YNNinterface target) {
        if(DEF_DEBUG) Log.d(LOG, "YNNFragmentDialog with parameters");
    }

    @Override
    // ################################################
    public Dialog onCreateDialog(Bundle savedInstanceState){
    // ################################################
        if (DEF_DEBUG) Log.d(LOG, "onCreateDialog");
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

        int imageResource = android.R.drawable.ic_dialog_alert;
        Drawable image = getResources().getDrawable(imageResource);

        builder.setTitle(mTitle)
        .setMessage(mMessage)
        .setIcon(mImage)
        .setCancelable(mCancelable)

        .setPositiveButton("yes", new DialogInterface.OnClickListener() {
             @Override
             public void onClick(DialogInterface dialog, int id) {

                FragmentManager fm = getActivity().getSupportFragmentManager();
                mTarget.onDialogClick(dialog, id, 0, RESULT_POSITIVE); // generate a Nullpointer Exception
                dialog.dismiss();
               }
        })

        .setNegativeButton("no", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int id) {
                FragmentManager fm = getActivity().getSupportFragmentManager();
                mTarget.onDialogClick(dialog, id, 0, RESULT_NEGATIVE);
                dialog.dismiss();
                }
        });

        builder.setCancelable(mCancelable);

        if (mCancelable) {
                builder.setOnCancelListener(new OnCancelListener() {
                    @Override
                    public void onCancel(DialogInterface  arg0) {
                        mTarget.onDialogClick(null, 0, mRequest_tag, RESULT_NEUTRAL);
                        arg0.dismiss();
                    }
                });
            }

        return builder.create();
        }
    // ################################################
    public YNNfragmentDialog() {
    // ################################################
        if (DEF_DEBUG) Log.d(LOG, "YNNFragmentDiaog with no parameter");
        // TODO NO Auto-generated constructor stub
    }

}

import android.content.DialogInterface;

 public interface YNNinterface {
    public void onDialogClick(DialogInterface dialog, int id, int request_tag, int retValue);
 }

package at.bomsbg.MindX;

import android.app.Activity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import at.bomsbg.DialogConstants;
import at.bomsbg.YNNfragmentDialog;
import at.bomsbg.YNNinterface;

public class testCodeFragment extends Fragment implements DialogConstants, MindXconstants {
    private final String LOG = this.getClass().getSimpleName();
    public static final String EXTRA_CARD_ID = "at.bomsbg.card_id";
    private static final String DIALOG_CHOOSE = "Choose";
    private static final int REQUEST_CHANGE = 0;
    private Button startBtn;

    public static testCodeFragment newInstance(int myID){
        Bundle args = new Bundle();
        args.putSerializable(EXTRA_CARD_ID, myID);

        testCodeFragment fragment = new testCodeFragment();
        fragment.setArguments(args);

        return fragment;
    }   

    // ################################################ 
    public void onCreate(Bundle savedInstanceState) {
    // ################################################
        if(DEF_DEBUG) Log.d(LOG, "onCreate");
        super.onCreate(savedInstanceState);

    }

    // ################################################ 
    public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedStateInstance) {    
    // ################################################ 
        if(DEF_DEBUG) Log.d("testCodeFragment", "onCreateView called");
        View v = inflater.inflate(R.layout.testcode, parent, false);

        startBtn = (Button) v.findViewById(R.id.button1);

        startBtn.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                doMethode();
            }
        });
        return v;
    }       

    // ################################################ 
    private void doMethode() {
    // ################################################ 
        if(DEF_DEBUG) Log.d(LOG, "doMethode");
        callDialog(PICK_YN);
    }

    // ################################################    
    public void callDialog(int pintRequestCode) {
    // ################################################
        if(DEF_DEBUG) Log.d(LOG, "callDialog");
        int pintDialogType = PICK_YN;
        String pstrTitle = "Title of Dialogbox";
        String pstrMsg = "show a MessageDetail";
        boolean pbolCancelable = true;
        YNNinterface pbolInterface = null;
        // call Dialog with returnValue
        FragmentManager fm = getActivity().getSupportFragmentManager();
        YNNfragmentDialog dialog = YNNfragmentDialog.newInstance(getContext(), pintDialogType, pstrTitle, pstrMsg, pbolCancelable, pbolInterface);
        dialog.setTargetFragment(testCodeFragment.this, REQUEST_CHANGE);
        dialog.show(fm, DIALOG_CHOOSE);
//        dialog.dismiss(); not here !!!
    }

    @Override
    // ################################################
    public void onActivityResult(int requestCode, int resultCode, Intent data){
    // ################################################
        if(DEF_DEBUG) Log.d(LOG, "onActivityResult");

        if (resultCode != Activity.RESULT_OK) return;
        if (requestCode == REQUEST_CHANGE) {
//            Date date = (Date) data.getSerializableExtra(DatePickerFragment.EXTRA_DATE);
//            if (date == null) {
//                date = (Date) data.getSerializableExtra(TimePickerFragment.EXTRA_TIME);
            }
//            mCrime.setDate(date);
//            updateDate();
        }


    // ################################################
    public void onDialogClick(DialogInterface tobjialog, int tintID, int tint_request, int tint_Value) {
    // ################################################
        // TODO NO Auto-generated method stub
//      public void onDialogClick(DialogInterface dialog, int id, int request_tag, int retValue);

//      YNNfragmentDialog(Context tobjContext, final int tintrequest_tag, String tstrTitle, 
//      String tstrMessage, boolean tbolCancelable, final YNNinterface target) {

//      YNNfragmentDialog myDialog = new YNNfragmentDialog();
        Log.d(LOG, "onDialogClick from testcode wtih return VAlue" + Integer.toString(tint_Value));
    }
}

public interface DialogConstants {
    public static final String  DIALOG_WARN = "WARNING";
    public static final String  DIALOG_YN = "YESNO";
    public static final String  SIALOG_INFO = "INFO";
    public static final String  DIALOG_YNC= "YESNOCANCEL";
    public static final String  DIALOG_ANSWER = "extra_answer";
    public static final String  DIALOG_TITLE = "extra_title";
    public static final String  DIALOG_MESS = "extra_mess";
    public static final String  DIALOG_DATE = "DATE";
    public static final String  DIALOG_TIME = "TIME";
    public static final String  DIALOG_DATETIME = "DATETIME";

    public static final int RESULT_OK = 0;
    public static final int RESULT_POSITIVE = 2;
    public static final int RESULT_NEGATIVE = 3;
    public static final int RESULT_NEUTRAL = 4;

    public static final String  STATE_RECNO  = "recno";

    // Requests
    public static final int TAG_DELETE = 11;
    public static final int TAG_DELETE_REC = 12;
    public static final int TAG_RESET = 13;
    public static final int TAG_RESET_TEST = 14;
    public static final int TAG_EXIT = 19;


    public static final int PICK_OK = 20;
    public static final int PICK_YN = 21;
    public static final int PICK_DATE = 22;
    public static final int PICK_TIME = 23;
    public static final int PICK_DATEWTIME = 24;

    public static final int PICK_QUESTION_IMAGE = 91;
    public static final int PICK_ANSWER_IMAGE = 92;

}