SliderPreference: Fix crash when rounding value

lawnchair/src/app/lawnchair/ui/preferences/SliderPreference.kt

@@ -7,7 +7,7 @@ import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
-import java.text.DecimalFormat
+import app.lawnchair.util.round
 import kotlin.math.roundToInt
 
 @Composable
@@ -37,7 +37,7 @@ fun SliderPreference(
                 ) {
                     Text(
                         text = if (showAsPercentage) {
-                            "${(DecimalFormat("#.#").format(value).toFloat() * 100).toInt()}%"
+                            "${(value.round(2) * 100).toInt()}%"
                         } else {
                             "${value.roundToInt()}"
                         }

lawnchair/src/app/lawnchair/util/Math.kt

@@ -0,0 +1,15 @@
+package app.lawnchair.util
+
+import java.text.DecimalFormat
+import java.text.DecimalFormatSymbols
+
+fun Float.round(decimals: Int): Float {
+    val symbols = DecimalFormatSymbols()
+    symbols.decimalSeparator = '.'
+    val format = DecimalFormat()
+    format.decimalFormatSymbols = symbols
+    format.applyPattern(
+        "#.${"#".repeat(decimals)}"
+    )
+    return format.format(this).toFloat()
+}