Question

我是数据库中的新手。我正在尝试创建一个应用程序，将任何已发送的SMS（安装此应用程序后）从SentBox插入SQLite数据库。如果make Toast而不是将细节插入数据库，它可以正常工作。但是当我尝试将其插入数据库时，它会给出NullPointerException。

LogCat错误：

09-29 13:19:54.999: E/AndroidRuntime(3059): FATAL EXCEPTION: main
09-29 13:19:54.999: E/AndroidRuntime(3059): Process: com.manish.smshistory, PID: 3059
09-29 13:19:54.999: E/AndroidRuntime(3059): java.lang.NullPointerException
09-29 13:19:54.999: E/AndroidRuntime(3059):     at com.manish.smshistory.MainActivity.getSMSDetails(MainActivity.java:95)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at com.manish.smshistory.MainActivity$1.onClick(MainActivity.java:41)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at android.view.View.performClick(View.java:4562)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at android.view.View$PerformClick.run(View.java:18918)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at android.os.Handler.handleCallback(Handler.java:808)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at android.os.Handler.dispatchMessage(Handler.java:103)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at android.os.Looper.loop(Looper.java:193)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at android.app.ActivityThread.main(ActivityThread.java:5388)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at java.lang.reflect.Method.invokeNative(Native Method)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at java.lang.reflect.Method.invoke(Method.java:515)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:655)
09-29 13:19:54.999: E/AndroidRuntime(3059):     at dalvik.system.NativeStart.main(Native Method)

数据库：

public class SMSSent extends SQLiteOpenHelper {

    public SMSSent(Context context, String name, CursorFactory factory,
            int version) {
        super(context, name, factory, version);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub

        db.execSQL("CREATE TABLE Sent_SMS_Table (Id INTEGER PRIMARY KEY AUTOINCREMENT, Source TEXT, Dttm TEXT, Msg TEXT, Type TXT);");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }

}

主要活动：

public class MainActivity extends Activity {

    TextView textView;
    SMSSent st;
    Button Save, Next;
    String body, dttm;

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


        Save = (Button)findViewById(R.id.Save);
        Save.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                getSMSDetails();

            }


        });

        Next = (Button)findViewById(R.id.Next);
        Next.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                startActivity(new Intent(MainActivity.this, RetrieveSMS.class));
            }
        });

    }  // onCreate ends

    public void getSMSDetails() {
        // TODO Auto-generated method stub


            Uri uri = Uri.parse("content://sms/sent");
            Cursor cursor = getContentResolver().query(uri, null, null, null, null);

            if (cursor.moveToFirst()) {
                for (int i = 0; i < cursor.getCount(); i++) {
                     body = cursor.getString(cursor.getColumnIndexOrThrow("body"))
                            .toString();

                    String date = cursor.getString(cursor.getColumnIndexOrThrow("date"))
                            .toString();
                    Date smsDayTime = new Date(Long.valueOf(date));
                    dttm = smsDayTime.toString();

                    SQLiteDatabase db=st.getWritableDatabase();
                    ContentValues values=new ContentValues();
                    values.put("Source", "Self");
                    values.put("Dttm", dttm);
                    values.put("Msg", body);
                    values.put("Type", "OUT");
                    db.insert("Sent_SMS_Table", "Source", values);
                    db.close();



                    cursor.moveToNext();

                }

            }
            cursor.close();


    }




} // Activity ends

Answer 1

看起来问题与

有关

SQLiteDatabase db=st.getWritableDatabase();

试

SMSSent st = new SMSSent();

SQLiteDatabase db=st.getWritableDatabase();

希望这有帮助

Answer 2

嗨问题是如果你想使用autoincrement id只是在代码下面使用自动增量关键字

@Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub

        db.execSQL("CREATE TABLE Sent_SMS_Table (id INTEGER PRIMARY KEY, Source TEXT, Dttm TEXT, Msg TEXT, Type TEXT);");
    }

将已发送的SMS插入SQLite数据库

2 个答案: