Question

我正在尝试将数据发送到SQLite并从中获取数据到ArrayList。为此，我使用了helper类和getter / setter方法。请建议我更正此代码。

这是助手类

public class Bday_Detail {

String name,full_date,ch;
int age;

public Bday_Detail(String name, String full_date, String ch, int age) {
    this.name = name;
    this.full_date = full_date;
    this.ch = ch;
    this.age = age;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getFull_date() {
    return full_date;
}

public void setFull_date(String full_date) {
    this.full_date = full_date;
}

public String getCh() {
    return ch;
}

public void setCh(String ch) {
    this.ch = ch;
}

public int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}

}

这是SQLiteConnection类

public class SQLiteConnection  {

    public  static final String DB_NAME = "birthday";
    public  static final String TBL_NAME = "birthday_details";
    public  static final String TBL_PK = "p_id";
    public  static final String TBL_COL1 = "p_name";
    public  static final String TBL_COL2 = "p_date";
    public  static final String TBL_COL3 = "p_age";
    public  static final String TBL_COL4 = "p_ch";


SQLiteDatabase sqLiteDatabase;
    Context context;

    public SQLiteConnection (Context context) {


        this.context = context;
    }

public  class connect extends SQLiteOpenHelper {
    public connect(Context context) {
    super(context, DB_NAME, null, 1);
}


    @Override
    public void onCreate(SQLiteDatabase db) {
    String Create_BIO = "CREATE TABLE " + TBL_NAME + " (" + TBL_PK + " integer primary key autoincrement, "
            + TBL_COL1 + " text, " + TBL_COL2 + " text, " + TBL_COL3 + " integer , " + TBL_COL4 + " text   )";
    db.execSQL(Create_BIO);
    }

     @Override
    public void onUpgrade(SQLiteDatabase db, int i, int i1) {

    db.execSQL("DROP TABLE IF EXISTS birthday_details"+TBL_NAME);
    onCreate(db);

     }



}

public  void openDB(){
    sqLiteDatabase =  new  connect(context).getWritableDatabase();
}
public void  closeDB(){
    if (sqLiteDatabase.isOpen() && sqLiteDatabase != null){
        sqLiteDatabase.close();
    }

}
public long add_details(Bday_Detail student){

    ContentValues contentValues = new ContentValues();
    contentValues.put(TBL_COL1,student.getName());
    contentValues.put(TBL_COL2,student.getFull_date());
    contentValues.put(TBL_COL3,student.getAge());
    contentValues.put(TBL_COL4,student.getCh());

    return sqLiteDatabase.insert(TBL_NAME,null,contentValues);


}

public Cursor get_details() {
   String[] columns = new String[]{TBL_PK,TBL_COL1,TBL_COL2,TBL_COL3,TBL_COL4};
    Cursor cursor = sqLiteDatabase.query(TBL_NAME, null, null, null, null, null, null, null);
    String result = "";
    int iRow = cursor.getColumnIndex(TBL_PK);
    int iName = cursor.getColumnIndex(TBL_COL1);
    int iDate = cursor.getColumnIndex(TBL_COL2);
    int iAge = cursor.getColumnIndex(TBL_COL3);
    int iCh = cursor.getColumnIndex(TBL_COL4);
    for (cursor.moveToFirst(); !cursor.isAfterLast();cursor.moveToNext()){
        result  = result + cursor.getString(iRow)+ " " + cursor.getString(iName)+ " " +cursor.getString(iDate)+ " " +cursor.getString(iAge)+ " " +cursor.getString(iCh)+ "\n";

    }


   while (cursor.moveToNext()){
       Log.e(String.valueOf(cursor.getColumnCount()), "Cursor Log");

       Bday_Detail student = new Bday_Detail(cursor.getString(cursor.getColumnIndex(TBL_COL1)),
               cursor.getString(cursor.getColumnIndex(TBL_COL2)),
               cursor.getString(cursor.getColumnIndex(TBL_COL4)));
               cursor.getString(cursor.getColumnIndex(TBL_COL3)));
       obj.add(student);
    return cursor;
    }
    cursor.moveToFirst();
}

}

以下代码是我想要获取数据的activity

public class Add_activity extends AppCompatActivity {
TextView tv_date, tv_month, tv_submit;
DatePicker pickerDate;
EditText et_name;
SQLiteConnection sqLiteConnection;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add_activity);
    tv_date = (TextView) findViewById(R.id.view_date);
    et_name = (EditText) findViewById(R.id.et_name);
    pickerDate = (DatePicker) findViewById(R.id.pickerDate);

    tv_submit = (TextView) findViewById(R.id.submit);
    Calendar now = Calendar.getInstance();
    pickerDate.init(
            1998,
            now.get(Calendar.MONTH),
            now.get(Calendar.DAY_OF_MONTH),
            null);
    final int curr_year = now.get(Calendar.YEAR);
    tv_submit.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {



            Calendar cal = Calendar.getInstance();
            cal.set(pickerDate.getYear(),
                    pickerDate.getMonth(),
                    pickerDate.getDayOfMonth()
                    );

            String name = et_name.getText().toString();
                final int month = pickerDate.getMonth()+1;
                final int year = pickerDate.getYear();
                final int date = pickerDate.getDayOfMonth();
                final int age = curr_year-year;
            String fchar=name.substring(0,1);

                final  String full_date ;
            String finaldate =date+"/"+month+"/"+year;

            tv_date.setText("\n\n***\n"
                        + "Alarm is set@ " + finaldate +name+"   age:---  "+age+"  first char    "+fchar+"***\n");


            Bday_Detail bday_detail = new Bday_Detail(name,finaldate,fchar,age);
            sqLiteConnection.add_details(bday_detail);

        }
    });
}

}

Answer 1

这是因为您首先获取数据并在

之后设置其值

使用以下惯例

public void setAge(int age)
{
    this.age = age;
} 

public int getAge() {
    return age;
}

Answer 2

您没有打开数据库来编写和阅读

public long add_details(Bday_Detail student){

   openDB()     

   ContentValues contentValues = new ContentValues();
   contentValues.put(TBL_COL1,student.getName());
   contentValues.put(TBL_COL2,student.getFull_date());
   contentValues.put(TBL_COL3,student.getAge());
   contentValues.put(TBL_COL4,student.getCh());

   return sqLiteDatabase.insert(TBL_NAME,null,contentValues);
 }

同样适合阅读

public  void openDb(){
sqLiteDatabase =  new  connect(context).getReadableDatabase();
}

然后在get_detail（）方法

opneDb();

// rest of the code

closeDB();
}

无法通过帮助程序类getter setter在sqlite数据库中添加数据

2 个答案: