点击卡片打开活动

Question

好的，我用3张卡制作了基本的列表视图。 但点击任何一张牌似乎都无法开启新活动。 这个问题是什么？ 我如何让一张卡片开启一项新活动？ android：onClick在卡片视图的xml文件中设置。

我的片段：

public class Home_fragment extends Fragment {

private ListView mListView;
private cardAdapter itemAdapter;
private CardView mCardView;

public Home_fragment() {
    // Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View rootView = inflater.inflate(R.layout.fragment_home, container, false);
    mCardView = (CardView) rootView.findViewById(R.id.cardview);
    mListView = (ListView) rootView.findViewById(R.id.list);
    itemAdapter = new cardAdapter(getActivity());
    mListView.setAdapter(itemAdapter);
 mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            Intent intent = new Intent(getActivity(), Events_Activity.class);
            startActivity(intent);
        }

    });
    return rootView;
} 

}

class cardAdapter extends BaseAdapter{
private Context context;
String[] menu;

int images[] = {R.drawable.events,R.drawable.workshops,R.drawable.seminars};
public cardAdapter(Context context){
    this.context = context;
    menu = context.getResources().getStringArray(R.array.Home_menu);

}
@Override
public int getCount() {
    return menu.length;
}

@Override
public Object getItem(int i) {
    return menu[i];
}

@Override
public long getItemId(int i) {
    return i;
}


@Override
public View getView(int i, View view, ViewGroup viewGroup) {
    View row = null;
    if(view == null){
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
        row = inflater.inflate(R.layout.cards_menu,viewGroup,false);
    }
    else
    {
        row = viewGroup;
    }
    TextView titleTextView = (TextView) row.findViewById(R.id.cardtext);
    ImageView titleImageView = (ImageView) row.findViewById(R.id.cardimage);
    titleTextView.setText(menu[i]);
    titleImageView.setImageResource(images[i]);
    return row;    }
}

编辑：添加了logcat

12-19 13:27:40.830    2204-2204/com.cambridge.patils.citech E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.cambridge.patils.citech, PID: 2204
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.cambridge.patils.citech/com.cambridge.patils.citech.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
        at android.app.ActivityThread.access$800(ActivityThread.java:144)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5221)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
            at com.cambridge.patils.citech.Home_fragment.onCreateView(Home_fragment.java:55)
            at android.app.Fragment.performCreateView(Fragment.java:2053)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:894)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
        at android.app.BackStackRecord.run(BackStackRecord.java:833)
        at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1452)
        at android.app.Activity.performStart(Activity.java:5948)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)