refactor: extract 'KeyUtils' to :common:android

Simple KeyEvent digit helpers with no project dependencies. Lives in
:common:android since it uses android.view.KeyEvent.

Author: criticalAY

AnkiDroid/src/androidTest/java/com/ichi2/anki/utils/KeyUtilsTest.kt

@@ -92,6 +92,7 @@ import com.ichi2.anki.android.input.shortcut
 import com.ichi2.anki.common.annotations.NeedsTest
 import com.ichi2.anki.common.crashreporting.CrashReportService
 import com.ichi2.anki.common.utils.HashUtil
+import com.ichi2.anki.common.utils.android.digit
 import com.ichi2.anki.common.utils.android.showThemedToast
 import com.ichi2.anki.common.utils.annotation.KotlinCleanup
 import com.ichi2.anki.common.utils.ext.ifZero
@@ -170,7 +171,6 @@ import com.ichi2.utils.ClipboardUtil.hasMedia
 import com.ichi2.utils.ClipboardUtil.items
 import com.ichi2.utils.ImportUtils
 import com.ichi2.utils.IntentUtil.resolveMimeType
-import com.ichi2.utils.KeyUtils
 import com.ichi2.utils.NoteFieldDecorator
 import com.ichi2.utils.TextViewUtil
 import com.ichi2.utils.configureView
@@ -984,7 +984,6 @@ class NoteEditorFragment :
         textBox.setSelection(start + newStart, start + newEnd)
     }
 
-    @KotlinCleanup("convert KeyUtils to extension functions")
     override fun dispatchKeyEvent(event: KeyEvent): Boolean {
         // We want to behave as onKeyUp and thus only react to ACTION_UP
         if (event.action != KeyEvent.ACTION_UP) return false
@@ -1055,7 +1054,7 @@ class NoteEditorFragment :
 
         // 7573: Ctrl+Shift+[Num] to select a field
         if (event.isCtrlPressed && event.isShiftPressed) {
-            val digit = KeyUtils.getDigit(event) ?: return false
+            val digit = event.digit ?: return false
             // '0' is after '9' on the keyboard, so a user expects '10'
             val humanReadableDigit = if (digit == 0) 10 else digit
             // Subtract 1 to map to field index. '1' is the first field (index 0)

AnkiDroid/src/main/java/com/ichi2/anki/NoteEditorFragment.kt

@@ -13,20 +13,16 @@
  *  You should have received a copy of the GNU General Public License along with
  *  this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-package com.ichi2.utils
+package com.ichi2.anki.common.utils.android
 
 import android.view.KeyEvent
-import androidx.annotation.VisibleForTesting
 
-object KeyUtils {
-    @VisibleForTesting
-    fun isDigit(event: KeyEvent): Boolean {
-        val unicodeChar = event.getUnicodeChar(0)
-        return unicodeChar >= '0'.code && unicodeChar <= '9'.code
-    }
-
-    fun getDigit(event: KeyEvent): Int? {
-        val unicodeChar = event.getUnicodeChar(0)
-        return if (isDigit(event)) unicodeChar - '0'.code else null
+/**
+ * The decimal digit (0..9) represented by this [KeyEvent], or `null` if the event
+ * does not represent a digit.
+ */
+val KeyEvent.digit: Int?
+    get() {
+        val unicodeChar = getUnicodeChar(0)
+        return if (unicodeChar in '0'.code..'9'.code) unicodeChar - '0'.code else null
     }
-}

…rc/main/java/com/ichi2/utils/KeyUtils.kt …i2/anki/common/utils/android/KeyUtils.ktAnkiDroid/src/main/java/com/ichi2/utils/KeyUtils.kt renamed to common/android/src/main/java/com/ichi2/anki/common/utils/android/KeyUtils.kt AnkiDroid/src/main/java/com/ichi2/utils/KeyUtils.kt renamed to common/android/src/main/java/com/ichi2/anki/common/utils/android/KeyUtils.kt

@@ -14,44 +14,40 @@
  *  this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package com.ichi2.utils
+package com.ichi2.anki.common.utils.android
 
 import android.view.KeyEvent
 import android.view.KeyEvent.ACTION_UP
 import android.view.KeyEvent.KEYCODE_0
+import android.view.KeyEvent.KEYCODE_5
 import android.view.KeyEvent.KEYCODE_9
+import android.view.KeyEvent.KEYCODE_BACK
 import android.view.KeyEvent.KEYCODE_ENDCALL
 import android.view.KeyEvent.KEYCODE_STAR
 import androidx.test.ext.junit.runners.AndroidJUnit4
-import com.ichi2.anki.EmptyApplicationCategory
-import com.ichi2.testutils.EmptyApplication
-import com.ichi2.utils.KeyUtils.getDigit
-import com.ichi2.utils.KeyUtils.isDigit
-import org.junit.Assert.assertEquals
-import org.junit.Assert.assertFalse
-import org.junit.Assert.assertTrue
 import org.junit.Test
-import org.junit.experimental.categories.Category
 import org.junit.runner.RunWith
-import org.robolectric.annotation.Config
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
 
+/** Tests for [KeyEvent.digit]. */
 @RunWith(AndroidJUnit4::class)
-@Config(application = EmptyApplication::class)
-@Category(EmptyApplicationCategory::class)
 class KeyUtilsTest {
     @Test
-    fun testIsDigit() {
-        assertTrue(isDigit(KeyEvent(ACTION_UP, KEYCODE_0)))
-        assertTrue(isDigit(KeyEvent(ACTION_UP, KEYCODE_9)))
-        assertFalse(isDigit(KeyEvent(ACTION_UP, KEYCODE_STAR)))
-        assertFalse(isDigit(KeyEvent(ACTION_UP, KEYCODE_ENDCALL)))
+    fun `digit returns the digit for 0-9 keys`() {
+        assertEquals(0, KeyEvent(ACTION_UP, KEYCODE_0).digit)
+        assertEquals(5, KeyEvent(ACTION_UP, KEYCODE_5).digit)
+        assertEquals(9, KeyEvent(ACTION_UP, KEYCODE_9).digit)
     }
 
     @Test
-    fun testGetDigit() {
-        assertEquals(0, getDigit(KeyEvent(ACTION_UP, KEYCODE_0)))
-        assertEquals(9, getDigit(KeyEvent(ACTION_UP, KEYCODE_9)))
-        assertEquals(null, getDigit(KeyEvent(ACTION_UP, KEYCODE_STAR)))
-        assertEquals(null, getDigit(KeyEvent(ACTION_UP, KEYCODE_ENDCALL)))
+    fun `digit returns null for non-digit printable keys`() {
+        assertNull(KeyEvent(ACTION_UP, KEYCODE_STAR).digit)
+    }
+
+    @Test
+    fun `digit returns null for non-printable keys`() {
+        assertNull(KeyEvent(ACTION_UP, KEYCODE_ENDCALL).digit)
+        assertNull(KeyEvent(ACTION_UP, KEYCODE_BACK).digit)
     }
 }