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我试图通过按下按钮来打开一个活动，当我按下按钮时，activty 包含 5 个编辑文本和 1 个微调器，它不幸地显示正在关闭 login.apk。

这是注册.java的代码片段

public class Registration extends Activity {
EditText name,password,email,dob,design,cpassword;
Button submit,cancel;
Spinner gender;
SQLiteDatabase db;
String Gen;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.registration);
    name=(EditText)findViewById(R.id.editText1);
    email=(EditText) findViewById(R.id.editText2);
    gender=(Spinner) findViewById(R.id.spinner1);
    dob=(EditText) findViewById(R.id.editText3);
    design=(EditText) findViewById(R.id.editText4);
    password=(EditText) findViewById(R.id.editText5);
    cpassword=(EditText) findViewById(R.id.editText6);

    db=openOrCreateDatabase("MobWalletDB",MODE_PRIVATE, null);
    List<String> list=new ArrayList<String>();
    list.add("Male");
    list.add("Female");
    ArrayAdapter<String> mAdapter= new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,list);
    mAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    gender.setAdapter(mAdapter);

    submit.setOnClickListener(new View.OnClickListener() {

        public void onClick(View arg0) {

            MODELUserData userGivenDataObject=new MODELUserData(name.getText().toString()
                                                               ,email.getText().toString(),Gen,dob.getText().toString(),design.getText().toString(),password.getText().toString());

            if(QUERYUserReg.registerUser(db, userGivenDataObject)){
                Toast.makeText(getBaseContext(), "User Registered!!!", Toast.LENGTH_SHORT).show();
                startActivity(new Intent(Registration.this,Login.class));

            }else
                Toast.makeText(getBaseContext(), "Registration Failure!!!", Toast.LENGTH_SHORT).show();             

        }
    });

    gender.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View v, int in,
                long lg) {
            // TODO Auto-generated method stub
            Gen=parent.getItemAtPosition(in).toString();
        }
    });

}

}

并且 Logcat 显示以下错误

05-29 07:22:48.331: E/AndroidRuntime(13236): FATAL EXCEPTION: main05-29 07:22:48.331:     
E/AndroidRuntime(13236): java.lang.RuntimeException: Unable to start activity   ComponentInfo{com.example.login/com.example.login.Registration}: java.lang.NullPointerException
...
...

05-29 07:22:48.331: E/AndroidRuntime(13236): Caused by: java.lang.NullPointerException
05-29 07:22:48.331: E/AndroidRuntime(13236):    at com.example.login.Registration.onCreate(Registration.java:49)
05-29 07:22:48.331: E/AndroidRuntime(13236):    at android.app.Activity.performCreate(Activity.java:5104)
05-29 07:22:48.331: E/AndroidRuntime(13236):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
05-29 07:22:48.331: E/AndroidRuntime(13236):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
05-29 07:22:48.331: E/AndroidRuntime(13236):    ... 11 more

请告诉我错误是什么？
提前致谢

4

5 回答 5

1

我相信崩溃就在这里：

submit.setOnClickListener(new View.OnClickListener() {

您缺少一个：

submit = (Button) findViewById(R.id.submit); // Or whatever your ID is

您还需要初始化cancel.

于 2013-05-29T07:48:13.430 回答
0

试试这个代码：

submit = (Button) findViewById(R.id.yourID);
Submit.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View arg0) {
        // your code here
    }
}
于 2013-10-30T15:16:50.173 回答
0

初始化您的提交和取消按钮。您正在为未初始化的变量编写 onClickListener

submit = (Button) findViewById(R.id.id_of_your_submit_button);
cancel= (Button) findViewById(R.id.id_of_your_cancel_button);
于 2013-05-29T09:25:16.057 回答
0

你永远不会初始化submit. 在 Jave 中，您不能在没有创建对象的情况下声明和使用对象（您应该在其上调用 new 运算符）。可能你错过findViewById了submit

于 2013-05-29T07:47:41.143 回答
0

您的提交按钮 ID 未在注册活动中初始化。但是您在提交按钮上使用了 onclick 侦听器。所以首先对其进行了初始化。希望您的问题可以解决。

于 2013-05-29T12:11:36.993 回答