实例详解Android快速开发工具类总结

十四、单例工具类 SingletonUtils.java

public abstract class SingletonUtils<T> {
private T instance;
protected abstract T newInstance();
public final T getInstance() {
if (instance == null) {
synchronized (SingletonUtils.class) {
if (instance == null) {
instance = newInstance();
}
}
}
return instance;
}
}

十五、数据库工具类 SqliteUtils.java

public class SqliteUtils {
private static volatile SqliteUtils instance;
private DbHelper dbHelper;
private SQLiteDatabase db;
private SqliteUtils(Context context) {
dbHelper = new DbHelper(context);
db = dbHelper.getWritableDatabase();
}
public static SqliteUtils getInstance(Context context) {
if (instance == null) {
synchronized (SqliteUtils.class) {
if (instance == null) {
instance = new SqliteUtils(context);
}
}
}
return instance;
}
public SQLiteDatabase getDb() {
return db;
}
}

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