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;
}
模态
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,我正在尝试获取 logcat 中的表,但我不知道该怎么做。我知道代码是 Select * from <tablename>
但我该如何实现呢?我想查看表中的所有数据。
最佳答案
解决方案:
请按照以下步骤操作:
第一步:
在 DatabaseHelper
中创建以下方法类:
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 Activity 中:
声明一个全局对象:List<FavouritesHelper> AllData
在你的类(class)里。
第三步:
然后,添加此 AllData = new List<FavouritesHelper>();
在你的onCreate()
第四步:
插入数据后在您的 Activity 中写入:AllData = database.getAllData();
第五步:
使用以下语句将其打印在日志中:
for(FavouritesHelper helper : AllData) {
Log.e("values : ", helper.getName() + ", " + helper.getPhoneNumber() + ", " + helper.getFavourites());
}
就是这样。
尝试一下。希望它有帮助。
关于java - 如何在 Logcat 中显示 SQLite 表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/52466535/