TFT blinking refresh, how to fix?

Using Arduino Programming Questions
#1

I have been able to use this sample code, to refresh on a change.

void loop()
{
int x = analogRead(A0);
if (x != prevX)
{
// write prevX in white

// write x in black

// remember last value
prevX = x;
}
delay(250);
}

the problem is I need to overwrite the old value in black but it has already updates.
sample of my code below

// for tft write

// Read the value of the sensor
String sensorVal0 = String(sensors.getTempCByIndex(0));
String sensorVal1 = String(sensors.getTempCByIndex(1));

// convert the reading to a char array
sensorVal0.toCharArray(sensorPrintout1, 8);
sensorVal1.toCharArray(sensorPrintout0, 8);

//tft stable temp
String y = sensorVal0;
if (y != prevY)
{
Serial.println("YYYYYYYY");

TFTscreen.setTextSize(2);

TFTscreen.stroke(0, 0, 0);
TFTscreen.text(sensorPrintout0, 0, 60);
delay(2000);
TFTscreen.stroke(100, 255, 100);
TFTscreen.text(sensorPrintout0, 0, 60);

prevY = y;
}

screen : tft 1.8 SPI 128*160"
temp sensors: DS18B20
code from : ONE WIRE / DALLAS TEMP

thanks

#2

its seem the issue or solution is to know how to replace

TFTscreen.text(sensorPrintout0, 0, 60);

with

TFTscreen.text(prevY, 0, 60);

but I get an error

no matching function for call to 'TFT::text(String&, int, int)'

??

using a serial print I can see the data is correct for the job, but I don't know how to fix the code

thanks

#3