Question

菜单项

else if (id == R.id.favourites){
        if (item.isChecked()) item.setChecked(false);

        else item.setChecked(true);
        return true;

数据库助手

public class DatabaseHelper extends SQLiteOpenHelper {

// Table Name
public static final String TABLE_NAME = "Contacts";

// Table columns
public static final String ID = "ID";
public static final String Contact_Name = "Contact_Name";
public static final String Phone_Number = "Phone_Number";
public static final String Favourites = "Favourites";

// Database Information
static final String DB_NAME = "MessagePlus_Contacts";

// database version
static final int DB_VERSION = 1;

// Creating table query
private static final String CREATE_TABLE = "Create Table " + TABLE_NAME + "(" + ID
        + " INTEGER PRIMARY KEY AUTOINCREMENT, " + Contact_Name + " TEXT NOT NULL, " + Phone_Number + " INT NOT NULL, " + Favourites + " INT NOT NULL);";

public DatabaseHelper(Context context) {
    super(context, DB_NAME, null, DB_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
    onCreate(db);
}

public void insertData(String contactName, String phoneNumber) {

    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();

    values.put(DatabaseHelper.Contact_Name, contactName);
    values.put(DatabaseHelper.Phone_Number, phoneNumber);
    values.put(DatabaseHelper.Favourites, "No");

    db.insert(DatabaseHelper.TABLE_NAME, null, values);
    // close db connection
    db.close();
}

public int addToFavourites(String favourites) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(DatabaseHelper.Phone_Number, favourites);

    // updating row
***IM NOT SURE HOW TO WRITE THE QUERY***
}


public int getCount() {
    String countQuery = "SELECT * FROM " + DatabaseHelper.TABLE_NAME;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);

    int count = cursor.getCount();
    cursor.close();

    // return count
    return count;
}

} 我没有编写更新代码行...

当它被选中时，我希望数据库列说“是”，而当它未被选中时，我希望它说“否” ... sqlite的新手是如此不确定，我也想知道如何使检查和取消检查永久化，因为一旦我退出活动，它将不再被选中...

Answer 1

要保存复选框的状态，请使用 SharedPefrences

//globally declare it
    SharedPreferences.Editor editor;

    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.filters); 

    editor = getSharedPreferences("STATE", MODE_PRIVATE).edit();
     SharedPreferences settings = 
      PreferenceManager.getDefaultSharedPreferences(this);
    boolean state = settings.getBoolean("isChecked", false);
    if(state){
    //set the checkbox checked
    }else{
    //set the checkbox Unchecked
    }
    }
}


    else if (id == R.id.favourites){
            if (item.isChecked()) {
            item.setChecked(false);
            editor.putBoolean("isChecked", false)
             editor.apply();

            }

            else {
            item.setChecked(true);
             editor.putBoolean("isChecked", true)
             editor.apply();
            }
            return true;
      }

要更新数据库，请使用此

public int Update(int id) {
    SQLiteDatabase db = this.getWritableDatabase();
 
    ContentValues values = new ContentValues();
    values.put(Note.COLUMN_NOTE, "Yes");
 
    // updating row
    return db.update(Note.TABLE_NAME, values, Note.COLUMN_ID + " = ?",
            new String[]{String.valueOf(id)});

在onCreateOptionMenu上执行此操作

public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.options_menu, menu);
    //here fetch the data from shared prfrencess which done on oncrete
    //use if else here
    menu.findItem(R.id.two_week).setChecked(checked);
    return true;
}

Answer 2

ContentValues cv = new ContentValues();
cv.put(ColumnName, newValue);
db.update(TABLE_NAME, cv, Column + "= ?", new String[] {rowId});

有关更多讨论，see

更新SQLite数据

2 个答案: