Change the font size after interacting with SeekBar

Since it will lead to lags on the screen if we set the font scale to
system everytime the progress changes when we drag through the seekbar,
we change the behavior to be only changing the system font scale when users
release their finger from the seekbar.

Bug: 274395502
Test: Manually - attach videos to the bug
Test: atest FontScalingDialogTest
Change-Id: I3b4168414c93d847f10ce081d1617010f62c2e21

packages/SystemUI/src/com/android/systemui/accessibility/fontscaling/FontScalingDialog.kt

@@ -84,31 +84,41 @@ class FontScalingDialog(
 
         seekBarWithIconButtonsView.setOnSeekBarChangeListener(
             object : OnSeekBarChangeListener {
+                var isTrackingTouch = false
+
                 override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
-                    if (progress != lastProgress) {
-                        if (!fontSizeHasBeenChangedFromTile) {
-                            backgroundExecutor.execute { updateSecureSettingsIfNeeded() }
-                            fontSizeHasBeenChangedFromTile = true
-                        }
-
-                        backgroundExecutor.execute { updateFontScale(strEntryValues[progress]) }
-
-                        lastProgress = progress
+                    if (!isTrackingTouch) {
+                        // The seekbar progress is changed by icon buttons
+                        changeFontSize(progress)
                     }
                 }
 
                 override fun onStartTrackingTouch(seekBar: SeekBar) {
-                    // Do nothing
+                    isTrackingTouch = true
                 }
 
                 override fun onStopTrackingTouch(seekBar: SeekBar) {
-                    // Do nothing
+                    isTrackingTouch = false
+                    changeFontSize(seekBar.progress)
                 }
             }
         )
         doneButton.setOnClickListener { dismiss() }
     }
 
+    private fun changeFontSize(progress: Int) {
+        if (progress != lastProgress) {
+            if (!fontSizeHasBeenChangedFromTile) {
+                backgroundExecutor.execute { updateSecureSettingsIfNeeded() }
+                fontSizeHasBeenChangedFromTile = true
+            }
+
+            backgroundExecutor.execute { updateFontScale(strEntryValues[progress]) }
+
+            lastProgress = progress
+        }
+    }
+
     private fun fontSizeValueToIndex(value: Float): Int {
         var lastValue = strEntryValues[0].toFloat()
         for (i in 1 until strEntryValues.size) {

packages/SystemUI/tests/src/com/android/systemui/accessibility/fontscaling/FontScalingDialogTest.kt

@@ -26,6 +26,8 @@ import com.android.systemui.R
 import com.android.systemui.SysuiTestCase
 import com.android.systemui.common.ui.view.SeekBarWithIconButtonsView
 import com.android.systemui.util.concurrency.FakeExecutor
+import com.android.systemui.util.mockito.capture
+import com.android.systemui.util.mockito.whenever
 import com.android.systemui.util.settings.FakeSettings
 import com.android.systemui.util.settings.SecureSettings
 import com.android.systemui.util.settings.SystemSettings
@@ -34,6 +36,10 @@ import com.google.common.truth.Truth.assertThat
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
+import org.mockito.ArgumentCaptor
+import org.mockito.Captor
+import org.mockito.Mockito.spy
+import org.mockito.Mockito.verify
 import org.mockito.MockitoAnnotations
 
 private const val ON: Int = 1
@@ -53,6 +59,9 @@ class FontScalingDialogTest : SysuiTestCase() {
             .getResources()
             .getStringArray(com.android.settingslib.R.array.entryvalues_font_size)
 
+    @Captor
+    private lateinit var seekBarChangeCaptor: ArgumentCaptor<SeekBar.OnSeekBarChangeListener>
+
     @Before
     fun setUp() {
         MockitoAnnotations.initMocks(this)
@@ -61,7 +70,7 @@ class FontScalingDialogTest : SysuiTestCase() {
         secureSettings = FakeSettings()
         backgroundExecutor = FakeExecutor(FakeSystemClock())
         fontScalingDialog =
-            FontScalingDialog(mContext, systemSettings, secureSettings, backgroundExecutor)
+            spy(FontScalingDialog(mContext, systemSettings, secureSettings, backgroundExecutor))
     }
 
     @Test
@@ -70,7 +79,7 @@ class FontScalingDialogTest : SysuiTestCase() {
 
         val seekBar: SeekBar = fontScalingDialog.findViewById<SeekBar>(R.id.seekbar)!!
         val progress: Int = seekBar.getProgress()
-        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def = */ 1.0f)
+        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
 
         assertThat(currentScale).isEqualTo(fontSizeValueArray[progress].toFloat())
 
@@ -91,7 +100,7 @@ class FontScalingDialogTest : SysuiTestCase() {
         iconEndFrame.performClick()
         backgroundExecutor.runAllReady()
 
-        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def = */ 1.0f)
+        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
         assertThat(seekBar.getProgress()).isEqualTo(1)
         assertThat(currentScale).isEqualTo(fontSizeValueArray[1].toFloat())
 
@@ -112,7 +121,7 @@ class FontScalingDialogTest : SysuiTestCase() {
         iconStartFrame.performClick()
         backgroundExecutor.runAllReady()
 
-        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def = */ 1.0f)
+        val currentScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
         assertThat(seekBar.getProgress()).isEqualTo(fontSizeValueArray.size - 2)
         assertThat(currentScale)
             .isEqualTo(fontSizeValueArray[fontSizeValueArray.size - 2].toFloat())
@@ -141,4 +150,39 @@ class FontScalingDialogTest : SysuiTestCase() {
 
         fontScalingDialog.dismiss()
     }
+
+    @Test
+    fun dragSeekbar_systemFontSizeSettingsDoesNotChange() {
+        val slider: SeekBarWithIconButtonsView = spy(SeekBarWithIconButtonsView(mContext))
+        whenever(
+                fontScalingDialog.findViewById<SeekBarWithIconButtonsView>(R.id.font_scaling_slider)
+            )
+            .thenReturn(slider)
+        fontScalingDialog.show()
+        verify(slider).setOnSeekBarChangeListener(capture(seekBarChangeCaptor))
+        val seekBar: SeekBar = slider.findViewById(R.id.seekbar)!!
+
+        // Default seekbar progress for font size is 1, simulate dragging to 0 without
+        // releasing the finger.
+        seekBarChangeCaptor.value.onStartTrackingTouch(seekBar)
+        // Update seekbar progress. This will trigger onProgressChanged in the
+        // OnSeekBarChangeListener and the seekbar could get updated progress value
+        // in onStopTrackingTouch.
+        seekBar.progress = 0
+        backgroundExecutor.runAllReady()
+
+        // Verify that the scale of font size remains the default value 1.0f.
+        var systemScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
+        assertThat(systemScale).isEqualTo(1.0f)
+
+        // Simulate releasing the finger from the seekbar.
+        seekBarChangeCaptor.value.onStopTrackingTouch(seekBar)
+        backgroundExecutor.runAllReady()
+
+        // Verify that the scale of font size has been updated.
+        systemScale = systemSettings.getFloat(Settings.System.FONT_SCALE, /* def= */ 1.0f)
+        assertThat(systemScale).isEqualTo(fontSizeValueArray[0].toFloat())
+
+        fontScalingDialog.dismiss()
+    }
 }