android-emulator - 如何避免 java.lang.IllegalStateException：无法执行活动的方法

Question

在我的项目中，我正在与数据库进行交互，按下时我有一个按钮从三个不同的编辑文本中添加三个项目，例如名称（字符串）、idcardno（最大 4 位的整数）、电话号码（最大 10 位的整数）。在按下添加按钮时，它会产生如下异常..

09-19 01:28:31.491: E/AndroidRuntime(1160): FATAL EXCEPTION: main
09-19 01:28:31.491: E/AndroidRuntime(1160): java.lang.IllegalStateException: Could not execute method of the activity
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.view.View$1.onClick(View.java:3633)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.view.View.performClick(View.java:4240)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.view.View$PerformClick.run(View.java:17721)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.os.Handler.handleCallback(Handler.java:730)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.os.Handler.dispatchMessage(Handler.java:92)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.os.Looper.loop(Looper.java:137)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.app.ActivityThread.main(ActivityThread.java:5103)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.reflect.Method.invokeNative(Native Method)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.reflect.Method.invoke(Method.java:525)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at dalvik.system.NativeStart.main(Native Method)
09-19 01:28:31.491: E/AndroidRuntime(1160): Caused by: java.lang.reflect.InvocationTargetException
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.reflect.Method.invokeNative(Native Method)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.reflect.Method.invoke(Method.java:525)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at android.view.View$1.onClick(View.java:3628)
09-19 01:28:31.491: E/AndroidRuntime(1160):     ... 11 more
09-19 01:28:31.491: E/AndroidRuntime(1160): Caused by: java.lang.NumberFormatException: Invalid int: "4233494398"
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.Integer.invalidInt(Integer.java:138)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.Integer.parse(Integer.java:378)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.Integer.parseInt(Integer.java:366)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at java.lang.Integer.parseInt(Integer.java:332)
09-19 01:28:31.491: E/AndroidRuntime(1160):     at com.wordpress.smdaudhilbe.database.MainActivity.addData(MainActivity.java:59)
09-19 01:28:31.491: E/AndroidRuntime(1160):     ... 14 more
09-19 01:28:34.340: I/Process(1160): Sending signal. PID: 1160 SIG: 9

这是我的完整代码，

package com.wordpress.smdaudhilbe.database;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;

import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;


public class MainActivity extends Activity {

    public EditText nameField,idCardField,phoneField;
    public Button add,del,update;
    public Spinner spN;

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initViews();

        spN.setOnItemSelectedListener(new OnItemSelectedListener() 
        {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view,int position, long id) {
                nameField.setText(parent.getItemAtPosition(position - 1).toString());
                idCardField.setText(parent.getItemAtPosition(position).toString());
                phoneField.setText(parent.getItemAtPosition(position+1).toString());                
            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {

            }
        });
    }

    public void addData(View v) {
        initViews();

        DataBaseHelper dbH = new DataBaseHelper(getApplicationContext());

                        dbH.insertContact(nameField.getText().toString(),Integer.parseInt(idCardField.getText().toString()),Integer.parseInt(phoneField.getText().toString()));

    loadSpinner();

    return;
}

private void loadSpinner() {
    initViews();

    DataBaseHelper dbH = new DataBaseHelper(getApplicationContext());

    List<String> label = dbH.getIds();

    ArrayAdapter<String> adpt = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,label);

    spN.setAdapter(adpt);
}

    public void deleteData(View v) {
        initViews();

        DataBaseHelper dbH = new DataBaseHelper(getApplicationContext());

        dbH.deleteContact(Integer.parseInt(idCardField.getText().toString()));
    }

    private void initViews(){
        nameField = (EditText)findViewById(R.id.editText1name);
        idCardField = (EditText)findViewById(R.id.editText2idcard);
        phoneField = (EditText)findViewById(R.id.editText3phone);

        add = (Button)findViewById(R.id.button1);
        del = (Button)findViewById(R.id.button2);
        update = (Button)findViewById(R.id.button3);

        spN = (Spinner)findViewById(R.id.spinner1);
    }
}


class DataBaseHelper extends SQLiteOpenHelper{

        public DataBaseHelper(Context context) {
            super(context,"MyDataBase", null, 1);           
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("create table contacts(name text not null,idCard integer,phoneNumber integer(10));");    
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("drop table if exists contacts;");
        }

        public void insertContact(String name,int idcard,int phone) {
            SQLiteDatabase db = this.getWritableDatabase();

            ContentValues vals = new ContentValues();

            vals.put("name",name);
            vals.put("idCard", idcard);
            vals.put("phoneNumber", phone);

            db.insert("contacts", null, vals);
            db.close();
        }

        public void deleteContact(long idcard) {
            SQLiteDatabase db = this.getWritableDatabase();

            db.delete("contacts", "idCard=?",new String[] {String.valueOf(idcard)});

            db.close();
        }

        public List<String> getIds() {
            SQLiteDatabase db = this.getReadableDatabase();

            List<String> lst = new ArrayList<String>();

            Cursor cursor = db.rawQuery("select * from contacts;",null);

            if(cursor.moveToFirst()){
                do{
                    lst.add(cursor.getString(2));
                }while(cursor.moveToNext());
            }

            cursor.close();

            db.close();

            return lst;
        }
}

如何解决这个...？请帮助，我读到很多都指向此类问题的空指针异常。

供您参考，我的 main_activity.xml 是

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <EditText
        android:id="@+id/editText1name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10" >

        <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/editText2idcard"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="number"
        android:ems="10"
        android:digits="0123456789"
        android:maxLength="4" />

    <EditText
        android:id="@+id/editText3phone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="phone"
        android:ems="10"
        android:digits="0123456789"
        android:maxLength="10" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="add"
            android:onClick="addData" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="del" 
            android:onClick="deleteData"/>

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="update" 
            android:onClick="updateData"/>

    </LinearLayout>

    <Spinner
        android:id="@+id/spinner1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

更新：当我尝试使用时

try{
        dbH.insertContact(nameField.getText().toString(),Integer.parseInt(idCardField.getText().toString()),Integer.parseInt(phoneField.getText().toString()));
        }catch (Exception e){e.printStackTrace();}

addData() 方法，

我懂了，

09-19 02:33:39.485: E/AndroidRuntime(933): FATAL EXCEPTION: main
09-19 02:33:39.485: E/AndroidRuntime(933): java.lang.NullPointerException
09-19 02:33:39.485: E/AndroidRuntime(933):  at com.wordpress.smdaudhilbe.database.MainActivity$1.onItemSelected(MainActivity.java:41)
09-19 02:33:39.485: E/AndroidRuntime(933):  at android.widget.AdapterView.fireOnSelected(AdapterView.java:892)
09-19 02:33:39.485: E/AndroidRuntime(933):  at android.widget.AdapterView.access$200(AdapterView.java:49)
09-19 02:33:39.485: E/AndroidRuntime(933):  at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:860)
09-19 02:33:39.485: E/AndroidRuntime(933):  at android.os.Handler.handleCallback(Handler.java:730)
09-19 02:33:39.485: E/AndroidRuntime(933):  at android.os.Handler.dispatchMessage(Handler.java:92)
09-19 02:33:39.485: E/AndroidRuntime(933):  at android.os.Looper.loop(Looper.java:137)
09-19 02:33:39.485: E/AndroidRuntime(933):  at android.app.ActivityThread.main(ActivityThread.java:5103)
09-19 02:33:39.485: E/AndroidRuntime(933):  at java.lang.reflect.Method.invokeNative(Native Method)
09-19 02:33:39.485: E/AndroidRuntime(933):  at java.lang.reflect.Method.invoke(Method.java:525)
09-19 02:33:39.485: E/AndroidRuntime(933):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-19 02:33:39.485: E/AndroidRuntime(933):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-19 02:33:39.485: E/AndroidRuntime(933):  at dalvik.system.NativeStart.main(Native Method)
09-19 02:33:42.555: I/Process(933): Sending signal. PID: 933 SIG: 9

我不认为，我犯了任何错误。使用 initViews() 方法，

private void initViews(){
        nameField = (EditText)findViewById(R.id.editText1name);
        idCardField = (EditText)findViewById(R.id.editText2idcard);
        phoneField = (EditText)findViewById(R.id.editText3phone);

        add = (Button)findViewById(R.id.button1);
        del = (Button)findViewById(R.id.button2);
        update = (Button)findViewById(R.id.button3);

        spN = (Spinner)findViewById(R.id.spinner1);
    }

我已经初始化了所有字段

我还公开了每个领域。

public EditText nameField,idCardField,phoneField;
    public Button add,del,update;
    public Spinner spN;

请帮助追查原因。