当我尝试从自动完成文本获取getText（）时，Android Prorgram崩溃

Question

I am trying to build an android app that allows you to input text, and will then transfer the text to the main screen. It allows me to build the autocomplete with no issue, but whenever i try to invoke the getText() function, the entire program crashes. Any help would be highly appreciated, thank you

     public class TeamFragment extends DialogFragment {
TextView team1, team2, score1, score2;



    AutoCompleteTextView team1input;



public TeamFragment(View t1, View t2, View s1, View s2) {
    team1=(TextView) t1;
    team2=(TextView) t2;
    score1=(TextView) s1;
    score2=(TextView) s2;
}

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.team_score_layout, container);
    //mEditText = (EditText) view.findViewById(R.id.txt_your_name);
    getDialog().setTitle("Enter Team Name");
    Button b = (Button) view.findViewById(R.id.teamButton);

    b.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            team1input=(AutoCompleteTextView) v.findViewById(R.id.autoCompleteTeam1);
            team1input.getText();         //crashes here
            team1.setText("hi");
            dismiss();
        }
    });
    return view;
}


}

here is the logCat, I appear to be getting a nullpointerexception.

04-23 13:12:33.628: E/AndroidRuntime(902): FATAL EXCEPTION: main
04-23 13:12:33.628: E/AndroidRuntime(902): java.lang.NullPointerException
04-23 13:12:33.628: E/AndroidRuntime(902):  at com.example.ucsb.cs.cs185.dimberman.nba.TeamFragment$1.onClick(TeamFragment.java:42)
04-23 13:12:33.628: E/AndroidRuntime(902):  at android.view.View.performClick(View.java:2485)
04-23 13:12:33.628: E/AndroidRuntime(902):  at android.view.View$PerformClick.run(View.java:9080)
04-23 13:12:33.628: E/AndroidRuntime(902):  at android.os.Handler.handleCallback(Handler.java:587)
04-23 13:12:33.628: E/AndroidRuntime(902):  at android.os.Handler.dispatchMessage(Handler.java:92)
04-23 13:12:33.628: E/AndroidRuntime(902):  at android.os.Looper.loop(Looper.java:123)
04-23 13:12:33.628: E/AndroidRuntime(902):  at android.app.ActivityThread.main(ActivityThread.java:3683)
04-23 13:12:33.628: E/AndroidRuntime(902):  at java.lang.reflect.Method.invokeNative(Native Method)
04-23 13:12:33.628: E/AndroidRuntime(902):  at java.lang.reflect.Method.invoke(Method.java:507)
04-23 13:12:33.628: E/AndroidRuntime(902):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-23 13:12:33.628: E/AndroidRuntime(902):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-23 13:12:33.628: E/AndroidRuntime(902):  at dalvik.system.NativeStart.main(Native Method)

`

Answer 1

Use team1input = (AutoCompleteTextView) view.findViewById(R.id.autoCompleteTeam1) in the onCreateView() method and delete the similar line in the onClick() method.

(Assuming you have the AutoCompleteTextView with autoCompleteTeam1 id defined in the team_score_layout.xml layout file.)

Answer 2

When you call findViewById() under a view class it finds child views of that class.

When the onClick is triggered, View v passed into onClick() is the button. If the AutoCompleteView you are trying to retrieve is not a child of that button then calling v.findViewById() will give you NullPointerException , since the view does not exist under the button's children tree.

Answer 3

Just replace

        team1input=(AutoCompleteTextView) v.findViewById(R.id.autoCompleteTeam1);

with

        team1input=(AutoCompleteTextView) view.findViewById(R.id.autoCompleteTeam1);