我创建了一个函数,用于更新我需要在多个视图上使用的数据库中的某些值。现在每个类都有自己的代码副本。基本上我读取了值,然后想要更新文本视图。
我为DisplayTop创建了一个完成工作的课程,并在本地实现了它的优秀。但不知何故,我需要通过我认为的函数发送(TextView)findViewById。我希望我这么说。那么对此的调用是什么以及如何解决(TextView)findViewById。谢谢你的帮助!
public void DisplayTop2()
{
int UserID = 1;
String D=Fun.getCurrentDateString();
String Sql;
Double a = 0.0;
Double b = 0.0;
SQLiteDatabase Db;
String myPath = DB_PATH + DB_NAME;
Db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
Sql =" SELECT a,b " +
" FROM test " +
" where Dte = '" + D + "' and UserID = " + UserID;
try {
Cursor c = Db.rawQuery(Sql, null);
if (c != null ) {
if (c.moveToFirst()) {
do {
a += (c.getDouble(c.getColumnIndex("a")));
b += (c.getDouble(c.getColumnIndex("b")));
}while (c.moveToNext());
}
}
c.close();
} catch (Exception e) {
}
Db.close();
// Here is where the problem is. The real app has 5 fields.
// I can pass the R.id.a
// But how do I pass the reference to findViewById to the activity that called this
TextView tvt4 = (TextView)findViewById(R.id.a);
D = Fun.round( a,1,BigDecimal.ROUND_HALF_UP);
tvt4.setText( D ) ;
tvt4 = (TextView)findViewById(R.id.b);
D = Fun.round( b,1,BigDecimal.ROUND_HALF_UP);
tvt4.setText( D ) ;
};
答案 0 :(得分:3)
我想我会尝试将所有UI更新保留在Activity
中,而不是传递TextView
个对象。为什么不创建一个Bean
来填充并返回到调用活动?类似的东西:
public class Mybean {
private String fieldA;
private String fieldB;
// create constructor and getters and setters here
}
然后填充并返回数据库代码中的bean。
public MyBean DisplayTop2() {
...
MyBean bean = new MyBean();
bean.setFieldA(Fun.round( a,1,BigDecimal.ROUND_HALF_UP));
bean.setFieldB(Fun.round( b,1,BigDecimal.ROUND_HALF_UP));
return bean;
}
然后在Activity
:
...
MyBean bean = MyDBClass.DisplayTop2();
TextView txtA = (TextView)findViewById(R.id.mytextviewA);
TextView txtB = (TextView)findViewById(R.id.mytextviewB);
txtA.setText(bean.getFieldA());
txtB.setText(bean.getFieldB());
这样可以将所有UI代码与数据库代码分开。