Android程序崩溃时，我试图从一个自动完成文本getText()

Question

我正在尝试构建一个android应用程序，允许您输入文本，然后将文本转移到主屏幕。它允许我在没有问题的情况下构建自动完成，但是每当我试图调用getText()函数时，整个程序都会崩溃。任何帮助都将非常感激，谢谢。

     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;
}

}

这里是logCat，我似乎得到一个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)

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Answer 1

在onCreateView()方法中使用team1input = (AutoCompleteTextView) view.findViewById(R.id.autoCompleteTeam1)，在onClick()方法中删除类似的行

(假设您在team_score_layout.xml布局文件中定义了autoCompleteTeam1 id的AutoCompleteTextView)

Answer 2

当你在一个视图类下调用findViewById()时，它会找到那个类的子视图。

onClick触发时，传递到onClick()的View v为按钮。如果你试图检索的AutoCompleteView不是该按钮的子按钮，那么调用v.findViewById()将给你NullPointerException，因为视图不存在于按钮的子树下。

Answer 3

直接替换

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

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