Only allow digits in custom download range dialog (closes #6220)

app/src/main/java/eu/kanade/tachiyomi/widget/DialogCustomDownloadView.kt

@@ -1,11 +1,14 @@
 package eu.kanade.tachiyomi.widget
 
 import android.content.Context
+import android.text.InputFilter
 import android.text.SpannableStringBuilder
+import android.text.Spanned
 import android.util.AttributeSet
 import android.view.LayoutInflater
 import android.view.View
 import android.widget.LinearLayout
+import androidx.core.text.isDigitsOnly
 import androidx.core.widget.doOnTextChanged
 import eu.kanade.tachiyomi.databinding.DownloadCustomAmountBinding
 import eu.kanade.tachiyomi.util.system.logcat
@@ -45,6 +48,7 @@ class DialogCustomDownloadView @JvmOverloads constructor(context: Context, attrs
 
         // Set download count to 0.
         binding.myNumber.text = SpannableStringBuilder(getAmount(0).toString())
+        binding.myNumber.filters = arrayOf(DigitInputFilter())
 
         // When user presses button decrease amount by 10.
         binding.btnDecrease10.setOnClickListener {
@@ -102,3 +106,20 @@ class DialogCustomDownloadView @JvmOverloads constructor(context: Context, attrs
         }
     }
 }
+
+private class DigitInputFilter : InputFilter {
+
+    override fun filter(
+        source: CharSequence,
+        start: Int,
+        end: Int,
+        dest: Spanned,
+        dstart: Int,
+        dend: Int,
+    ): CharSequence {
+        return when {
+            source.toString().isDigitsOnly() -> source.toString()
+            else -> ""
+        }
+    }
+}