データベースを使用しているときに問題が発生しました。null ポインター例外が発生し、解決できません。ここで私のコード、なぜこのエラーが発生するのかわかりませんが、友人の追加メソッドからスローされると確信しています
データベース.java
public class frienddatabase extends SQLiteOpenHelper {
public static String databasename="frienddatabase";
public static int databaseVersion =6;
public String tablename="friends";
public String id="_id";
public String name="name";
public String email="email";
public String phone="phone";
public String pic="pic";
public String age="age";
public String edu="edu";
コンストラクター:
public frienddatabase(Context context) {
super(context,databasename,null,databaseVersion);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
String create = "CREATE TABLE "+tablename+"("+id+" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"+name+" Text unique Not null,"+
email+" TEXT NOT NULL,"+phone+" TEXT NOT NULL,"+pic+" TEXT,"+age+" TEXT NOT NULL,"+edu+" TEXT NOT NULL"+")";
db.execSQL(create);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+tablename);
onCreate(db);
}
これは私が使用して取得しようとする機能ですNullPointer Exception
public boolean addFriend(String Fname,String Femail,String Fphone,String Fage,String Fedu)
{
SQLiteDatabase db=this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(name, Fname);
cv.put(email, Femail);
cv.put(phone, Fphone);
cv.put(age, Fage);
cv.put(edu, Fedu);
db.insert(tablename, pic, cv);
db.close();
return true;
}
addfriend メソッドを使用しようとするとエラーが発生します。ここでは、addfriend クラスで addfriend メソッドを呼び出します。
public class addfriend extends Activity {
EditText name,email,mobile,age,edu;
Button save,cancel,addimage;
frienddatabase helper;
String namex;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.add);
name=(EditText)findViewById(R.id.name);
email=(EditText)findViewById(R.id.email);
mobile=(EditText)findViewById(R.id.mobile);
age=(EditText)findViewById(R.id.age);
edu=(EditText)findViewById(R.id.edu);
save=(Button)findViewById(R.id.save);
cancel=(Button)findViewById(R.id.cancel);
addimage=(Button)findViewById(R.id.addimage);
helper=new frienddatabase(getApplicationContext());
save.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
namex=name.getText().toString();
Toast.makeText(getApplicationContext(),namex, Toast.LENGTH_LONG).show();
Boolean check = helper.addFriend(name.getText().toString(), email.getText().toString(), mobile.getText().toString(), age.getText().toString(), edu.getText().toString());
if(check==null)
{
Toast.makeText(getApplicationContext(), "null boolean",Toast.LENGTH_LONG).show();
}
if(check)
{
Toast.makeText(getApplicationContext(), "new friend added successfull!!", Toast.LENGTH_LONG).show();
}
else
{
Toast.makeText(getApplicationContext(), "data not saved ", Toast.LENGTH_LONG).show();
}
}
});
}
}
ここにも丸太猫
06-25 12:53:25.041: W/dalvikvm(1290): threadid=1: thread exiting with uncaught exception (group=0x409951f8)
06-25 12:53:25.061: E/AndroidRuntime(1290): FATAL EXCEPTION: main
06-25 12:53:25.061: E/AndroidRuntime(1290): java.lang.NullPointerException
06-25 12:53:25.061: E/AndroidRuntime(1290): at com.apk.addfriend$1.onClick(addfriend.java:38)
06-25 12:53:25.061: E/AndroidRuntime(1290): at android.view.View.performClick(View.java:3460)
06-25 12:53:25.061: E/AndroidRuntime(1290): at android.view.View$PerformClick.run(View.java:13955)
06-25 12:53:25.061: E/AndroidRuntime(1290): at android.os.Handler.handleCallback(Handler.java:605)
06-25 12:53:25.061: E/AndroidRuntime(1290): at android.os.Handler.dispatchMessage(Handler.java:92)
06-25 12:53:25.061: E/AndroidRuntime(1290): at android.os.Looper.loop(Looper.java:137)
06-25 12:53:25.061: E/AndroidRuntime(1290): at android.app.ActivityThread.main(ActivityThread.java:4340)
06-25 12:53:25.061: E/AndroidRuntime(1290): at java.lang.reflect.Method.invokeNative(Native Method)
06-25 12:53:25.061: E/AndroidRuntime(1290): at java.lang.reflect.Method.invoke(Method.java:511)
06-25 12:53:25.061: E/AndroidRuntime(1290): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-25 12:53:25.061: E/AndroidRuntime(1290): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-25 12:53:25.061: E/AndroidRuntime(1290): at dalvik.system.NativeStart.main(Native Method)
何か助けてください??