Question

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 + " Boolean NOT NULL);";

private static final String Show_Table = "Select * From " + TABLE_NAME;

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 showData(SQLiteDatabase db){db.execSQL(Show_Table);}

public void insertData(String contactName, String phoneNumber,String favourites) {

    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();

    values.put(DatabaseHelper.Contact_Name, contactName);
    values.put(DatabaseHelper.Phone_Number, phoneNumber);
    values.put(DatabaseHelper.Favourites, favourites);

    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.Favourites, favourites);

    // updating row
    return db.update(DatabaseHelper.TABLE_NAME, values, DatabaseHelper.Phone_Number + " = ?", new String[]{favourites});
}



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;
}

模式

public class FavouritesHelper {
public String Name;
public String PhoneNumber;
public boolean Favourites;

public FavouritesHelper() {
}

public FavouritesHelper(String Name, String PhoneNumber, Boolean Favourites) {
    this.Name = Name;
    this.PhoneNumber = PhoneNumber;
    this.Favourites = Favourites;
}
public String getName() {
    return Name;
}

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

public String getPhoneNumber() {
    return PhoneNumber;
}

public void setPhoneNumber(String PhoneNumber) {
    this.PhoneNumber = PhoneNumber;
}

public boolean getFavourites() {
    return Favourites;
}

public void setFavourites(boolean Favourites) {
    this.Favourites = Favourites;
}

}

这是我的数据库助手，我试图在logcat中获取表，但我不知道该怎么做。我知道代码是Select * from <tablename>，但是我该如何实现。我想查看表中的所有数据。

Answer 1

选择：

请按照以下步骤操作：

第一步：

在DatabaseHelper类中进行以下方法：

public List<FavouritesHelper> getAllData() {
    List<FavouritesHelper> data = new ArrayList<>();

    // Select All Query
    String selectQuery = "SELECT * FROM " + FavouritesHelper.TABLE_NAME;

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            FavouritesHelper alldata = new FavouritesHelper();

            alldata.setName(cursor.getString(cursor.getColumnIndex(FavouritesHelper.Name)));
            alldata.setPhoneNumber(cursor.getString(cursor.getColumnIndex(FavouritesHelper.PhoneNumber)));
            alldata.setFavourites(cursor.getBoolean(cursor.getColumnIndex(FavouritesHelper.Favourites)));

            data.add(alldata);
        } while (cursor.moveToNext());
    }

    // close db connection
    db.close();

    // return notes list
    return data;
}

第二步：

在您的活动中：

在类内部声明一个全局对象：List<FavouritesHelper> AllData。

第三步：

然后，将此AllData = new List<FavouritesHelper>();添加到您的onCreate()

第四步：

插入数据后，在您的活动中

将此内容写成：AllData = database.getAllData();

第五步：

使用以下语句在日志中打印它：

for(FavouritesHelper helper : AllData) {
     Log.e("values : ", helper.getName() + ", " + helper.getPhoneNumber() + ", " + helper.getFavourites());
}

就是这样。

尝试一下。希望对您有所帮助。

Answer 2

根据 @pskink 的建议，您可以像这样使用dumpCursor

在DatabaseHelper类中创建此方法

 public  void dumpCursorInLogCat() {

    //here first getting the readable database

            SQLiteDatabase db = this.getReadableDatabase();

            Cursor cursor = db.rawQuery(Show_Table, null);
      //here is how you can Dump cursor
            DatabaseUtils.dumpCursor(cursor);

            cursor.close();


        }

并在您想要在logcat中显示数据时在您的活动中调用此方法

在活动中称呼它，例如

new DatabaseHelper(your_activity_name.this).dumpCursorInLogCat();

如何在Logcat中显示SQLite表

2 个答案: