Ошибка is an invalid float

1. program Project1;

3. uses SysUtils;

5. var

6.   String1: string;

7.   Float1, Float2: Double;

8. begin

9. writeln(‘Start Testfloat’);

10.   Float1 := 0.0;

11.   Str(Float1,String1);

12. writeln(‘Float 1=<‘+String1+‘>’);

13.   Float2:= StrToFloat(String1);

14. end.

1. function PointStrToFloat(s: String): Double;

2. var

3.   fs: TFormatSettings;

4. begin

5.   fs := FormatSettings;

6.   fs.DecimalSeparator := ‘.’;

7.   Result := StrToFloat(s, fs);

8. end;

10. function PointFloatToStr(x: Double): String;

11. var

12.   fs: TFormatSettings;

13. begin

14.   fs := FormatSettings;

15.   fs.DecimalSeparator := ‘.’;

16.   Result := FloatToStr(x, fs);

17. end;

1. function PointStrToFloat(s: String): Double;

2. var

3.   res: Integer;

4. begin

5.   val(s, Result, res);

6. if res <> 0 then

7. raise EConvertError.Create(‘no valid numeric string’);

8. end;

1. function TFPReportVariable.GetValue: String;

2. begin

3. Case DataType of

4.     rtBoolean  : Result:=BoolToStr(AsBoolean,True);

5.     rtInteger  : Result:=IntToStr(AsInteger);

6.     rtFloat    : Str(AsFloat,Result);

7.     rtCurrency : Str(AsCurrency,Result);

8.     rtDateTime : Result:=DateTimeToISO8601(AsDateTime);

9.     rtString   : Result:=AsString

10. else

11. Raise EConvertError.CreateFmt(SErrUnknownResultType,[GetEnumName(TypeInfo(TResultType),Ord(DataType))])

12. end;

13. end;

1. procedure TTestVariable.TestFloat;

3. Var

4.   R : TFPExpressionResult;

6. begin

7.   Variable.DataType:=rtFloat;

8.   AssertEquals(‘Float type remains’,rtFloat,Variable.DataType);

9.   AssertEquals(‘Float default value’,0.0,Variable.AsFloat);

10.   AssertEquals(‘Float as string’,0.0,StrToFloat(Variable.Value)); // <- EConvertException

11.   Variable.DataType:=rtBoolean;

12.   Variable.AsFloat:=1.23;

13.   AssertEquals(‘Float type remains’,rtFloat,Variable.DataType);

14.   AssertEquals(‘Float as string’,1.23,StrToFloat(Variable.Value));

15.   AssertEquals(‘Float value’,1.23,Variable.AsFloat);

16.   R:=Variable.AsExpressionResult;

17.   AssertEquals(‘Correct result’,rtFloat,r.resulttype);

18.   AssertEquals(‘Correct value’,1.23,r.resFloat);

19.   ExpectException(‘Cannot fetch as other type’,EConvertError);

20.   Variable.AsString;

21. end;

1. {$mode delphi}{$H+}

2. program Project100;

3. uses SysUtils;

4. var

5.   String1: string;

6.   Float1, Float2: Double;

7. begin

8. writeln(‘Start Testfloat’);

9.   Float1 := 0.0;

10.   Str(Float1,String1);

11. writeln(‘Float 1=<‘+String1+‘>’);

12.   Float2:= StrToFloat(String1);

13. end.

1. program Project100;

3. uses

4.   SysUtils;

5. var

6.   String1: string[255];

7. //  String1: string;

8.   Float1, Float2: Double;

9. begin

10.   FormatSettings.DecimalSeparator := ‘,’;

11. writeln(‘Start Testfloat’);

12.   Float1 := 0.0;

13.   Str(Float1,String1);

14. writeln(‘Float 1=<‘+String1+‘>’);

15.   Float2:= StrToFloat(String1);

16. end.  

Хочеться прояснить ситуацию с TDBEdit. TDBEdit связан с числовым полем. Если ввести в него число, затем очистить, то при выходе из этого элемента возникает исключение EConvertError: » is an invalid float. Приходится присваивать Null полю в обработчике OnEditingDone:

Код: Выделить всё

if SQLQuery.State in [dsInsert, dsEdit] then
  if DBEdit.Text = '' then
    DBEdit.Field.Value := Null;


Похожая ситуация, если с DBEdit связано поле с типом Дата.

Компоненты используются стандартные.
Lazarus 0.9.30.2 + Firebird.

7bit писал(а):TDBEdit связан с числовым полем. Если ввести в него число, затем очистить, то при выходе из этого элемента возникает исключение

Не замечено ни разу
Использую порядка 300 tdbedit’ов — и в числовых значениях, и в строковых — полет нормальный….
Копайте код.

I’ve been following a lesson on how to constrain images within an activity window and, when I try to apply an aspect ratio of 1:1, the image moves away from it’s original intended location on the activity and up into the left hand corner of the activity as a 0dp x 0dp ImageView.

My code is saying this is an error of "Invalid Float":

app:layout_constraintDimensionRatio="1:1"

This is mysterious to me because the system ALSO tells me that the ratio can be listed as either a FLOAT or a RATIO. Someone tell me I’m not crazy and when I learned ratios as a kid they were separated by a colon.

I’ve removed the ImageViews multiple times and re-added constraints an equal RATIO amount of times. Still, Android Studio doesn’t know what a 1:1 ratio is. The constraint goes as follows:

Top Constraint
+ ImageView1
+ ImageView2
Bottom constraint
app:layout_constraintDimensionRatio="1:1"
Invalid Float

The ImageView is at the top of my activity window as a 0dp x 0dp image.

It seems that there was a change in the constraint layout implementation.

app:layout_constraintDimensionRatio=»W,661:165″

This does not work any longer. I get the message «Invalid float»

The solution is simple. This parameter now requires a float value. In the above example, all we have to do is to divide 665/165 = 4.006 (We can round the value to 4)

So this line now works as expected:

app:layout_constraintDimensionRatio=»4″

Hope this answer helps.

answered Jun 24, 2020 at 4:26

This question is totally valid and I couldn’t find an answer for that anywhere else.
The thing is, if you know what is a ratio and read the error carefully you notice that, for some reason, the layout wants you to use a float notation for it.

For example, if you want a ratio of 2:1 you want the width to be two times the height. Therefore you provide the ration like this width/height, since you want it 1 by 1 just put app:layout_constraintDimensionRatio="1" and be happy.

tl;dr: ratio 1:1 = 1/1 = 1 -> app:layout_constraintDimensionRatio="1"

answered Aug 15, 2019 at 19:54

I am not sure if this is exactly what you are looking for or if helps at all, but here is how I successfully was able to use it for my application. I believe the problem you are having might be the lack of constraints you have on the ImageView you are working with (which is why it might be going towards the top left of the screen). However, I cannot say this with confidence since I cannot see your code. I may be wrong since I am not a professional, but that is my best guess for now.

<ImageView
            android:id="@+id/userPicture"
            android:src="@drawable/user_picture"
            android:contentDescription="Update later"

            android:layout_width="125dp"
            android:layout_height="wrap_content"

            android:layout_marginStart="0dp"
            android:layout_marginEnd="0dp"
            android:layout_marginTop="40dp"
            android:layout_marginBottom="15dp"

            android:scaleType="centerCrop"
            android:adjustViewBounds="true"

            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintBottom_toTopOf="@id/currentTrackPlayingText"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"

            app:layout_constraintDimensionRatio="1:1" />

This produces the following that is constrained to other aspects of on the screen (Apologies, I do not have enough rep to show the image here).

link to example produced by above

answered Jul 25, 2019 at 19:29