widget: rewrite in kotlin

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

11 files changed, 359 insertions, 460 deletions

diff --git a/ui/src/main/java/com/wireguard/android/widget/EdgeToEdge.kt b/ui/src/main/java/com/wireguard/android/widget/EdgeToEdge.kt
index 544e9ddb..45b83aad 100644
--- a/ui/src/main/java/com/wireguard/android/widget/EdgeToEdge.kt
+++ b/ui/src/main/java/com/wireguard/android/widget/EdgeToEdge.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2017-2020 WireGuard LLC. All Rights Reserved.
+ * Copyright © 2020 WireGuard LLC. All Rights Reserved.
  * SPDX-License-Identifier: Apache-2.0
  */
 package com.wireguard.android.widget
@@ -15,7 +15,6 @@ import com.google.android.material.floatingactionbutton.ExtendedFloatingActionBu
  */
 
 object EdgeToEdge {
-
     @JvmStatic
     fun setUpRoot(root: ViewGroup) {
         root.systemUiVisibility =
diff --git a/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.java b/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.java
deleted file mode 100644
index 82c421cb..00000000
--- a/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.java
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android.widget;
-
-import android.text.InputFilter;
-import android.text.SpannableStringBuilder;
-import android.text.Spanned;
-
-import com.wireguard.crypto.Key;
-import com.wireguard.util.NonNullForAll;
-
-import androidx.annotation.Nullable;
-
-/**
- * InputFilter for entering WireGuard private/public keys encoded with base64.
- */
-
-@NonNullForAll
-public class KeyInputFilter implements InputFilter {
-    private static boolean isAllowed(final char c) {
-        return Character.isLetterOrDigit(c) || c == '+' || c == '/';
-    }
-
-    public static InputFilter newInstance() {
-        return new KeyInputFilter();
-    }
-
-    @Nullable
-    @Override
-    public CharSequence filter(final CharSequence source,
-                               final int sStart, final int sEnd,
-                               final Spanned dest,
-                               final int dStart, final int dEnd) {
-        SpannableStringBuilder replacement = null;
-        int rIndex = 0;
-        final int dLength = dest.length();
-        for (int sIndex = sStart; sIndex < sEnd; ++sIndex) {
-            final char c = source.charAt(sIndex);
-            final int dIndex = dStart + (sIndex - sStart);
-            // Restrict characters to the base64 character set.
-            // Ensure adding this character does not push the length over the limit.
-            if (((dIndex + 1 < Key.Format.BASE64.getLength() && isAllowed(c)) ||
-                    (dIndex + 1 == Key.Format.BASE64.getLength() && c == '=')) &&
-                    dLength + (sIndex - sStart) < Key.Format.BASE64.getLength()) {
-                ++rIndex;
-            } else {
-                if (replacement == null)
-                    replacement = new SpannableStringBuilder(source, sStart, sEnd);
-                replacement.delete(rIndex, rIndex + 1);
-            }
-        }
-        return replacement;
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.kt b/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.kt
new file mode 100644
index 00000000..951af699
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.kt
@@ -0,0 +1,46 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android.widget
+
+import android.text.InputFilter
+import android.text.SpannableStringBuilder
+import android.text.Spanned
+import com.wireguard.crypto.Key
+
+/**
+ * InputFilter for entering WireGuard private/public keys encoded with base64.
+ */
+class KeyInputFilter : InputFilter {
+    override fun filter(source: CharSequence,
+                        sStart: Int, sEnd: Int,
+                        dest: Spanned,
+                        dStart: Int, dEnd: Int): CharSequence? {
+        var replacement: SpannableStringBuilder? = null
+        var rIndex = 0
+        val dLength = dest.length
+        for (sIndex in sStart until sEnd) {
+            val c = source[sIndex]
+            val dIndex = dStart + (sIndex - sStart)
+            // Restrict characters to the base64 character set.
+            // Ensure adding this character does not push the length over the limit.
+            if ((dIndex + 1 < Key.Format.BASE64.length && isAllowed(c) ||
+                            dIndex + 1 == Key.Format.BASE64.length && c == '=') &&
+                    dLength + (sIndex - sStart) < Key.Format.BASE64.length) {
+                ++rIndex
+            } else {
+                if (replacement == null) replacement = SpannableStringBuilder(source, sStart, sEnd)
+                replacement.delete(rIndex, rIndex + 1)
+            }
+        }
+        return replacement
+    }
+
+    companion object {
+        private fun isAllowed(c: Char) = Character.isLetterOrDigit(c) || c == '+' || c == '/'
+
+        @JvmStatic
+        fun newInstance() = KeyInputFilter()
+    }
+}
diff --git a/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java b/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java
deleted file mode 100644
index aa0d08d9..00000000
--- a/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android.widget;
-
-import android.content.Context;
-import android.util.AttributeSet;
-import android.widget.RelativeLayout;
-
-import com.wireguard.android.R;
-import com.wireguard.util.NonNullForAll;
-
-@NonNullForAll
-public class MultiselectableRelativeLayout extends RelativeLayout {
-    private static final int[] STATE_MULTISELECTED = {R.attr.state_multiselected};
-    private boolean multiselected;
-
-    public MultiselectableRelativeLayout(final Context context) {
-        super(context);
-    }
-
-    public MultiselectableRelativeLayout(final Context context, final AttributeSet attrs) {
-        super(context, attrs);
-    }
-
-    public MultiselectableRelativeLayout(final Context context, final AttributeSet attrs, final int defStyleAttr) {
-        super(context, attrs, defStyleAttr);
-    }
-
-    public MultiselectableRelativeLayout(final Context context, final AttributeSet attrs, final int defStyleAttr, final int defStyleRes) {
-        super(context, attrs, defStyleAttr, defStyleRes);
-    }
-
-    @Override
-    protected int[] onCreateDrawableState(final int extraSpace) {
-        if (multiselected) {
-            final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
-            mergeDrawableStates(drawableState, STATE_MULTISELECTED);
-            return drawableState;
-        }
-        return super.onCreateDrawableState(extraSpace);
-    }
-
-    public void setMultiSelected(final boolean on) {
-        if (!multiselected) {
-            multiselected = true;
-            refreshDrawableState();
-        }
-        setActivated(on);
-    }
-
-    public void setSingleSelected(final boolean on) {
-        if (multiselected) {
-            multiselected = false;
-            refreshDrawableState();
-        }
-        setActivated(on);
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.kt b/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.kt
new file mode 100644
index 00000000..69ffefc0
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.kt
@@ -0,0 +1,49 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android.widget
+
+import android.content.Context
+import android.util.AttributeSet
+import android.view.View
+import android.widget.RelativeLayout
+import com.wireguard.android.R
+
+class MultiselectableRelativeLayout : RelativeLayout {
+    private var multiselected = false
+
+    constructor(context: Context?) : super(context) {}
+    constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs) {}
+    constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {}
+    constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes) {}
+
+    override fun onCreateDrawableState(extraSpace: Int): IntArray {
+        if (multiselected) {
+            val drawableState = super.onCreateDrawableState(extraSpace + 1)
+            View.mergeDrawableStates(drawableState, STATE_MULTISELECTED)
+            return drawableState
+        }
+        return super.onCreateDrawableState(extraSpace)
+    }
+
+    fun setMultiSelected(on: Boolean) {
+        if (!multiselected) {
+            multiselected = true
+            refreshDrawableState()
+        }
+        isActivated = on
+    }
+
+    fun setSingleSelected(on: Boolean) {
+        if (multiselected) {
+            multiselected = false
+            refreshDrawableState()
+        }
+        isActivated = on
+    }
+
+    companion object {
+        private val STATE_MULTISELECTED = intArrayOf(R.attr.state_multiselected)
+    }
+}
diff --git a/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.java b/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.java
deleted file mode 100644
index 32f4f262..00000000
--- a/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android.widget;
-
-import android.text.InputFilter;
-import android.text.SpannableStringBuilder;
-import android.text.Spanned;
-
-import com.wireguard.android.backend.Tunnel;
-import com.wireguard.util.NonNullForAll;
-
-import androidx.annotation.Nullable;
-
-/**
- * InputFilter for entering WireGuard configuration names (Linux interface names).
- */
-
-@NonNullForAll
-public class NameInputFilter implements InputFilter {
-    private static boolean isAllowed(final char c) {
-        return Character.isLetterOrDigit(c) || "_=+.-".indexOf(c) >= 0;
-    }
-
-    public static InputFilter newInstance() {
-        return new NameInputFilter();
-    }
-
-    @Nullable
-    @Override
-    public CharSequence filter(final CharSequence source,
-                               final int sStart, final int sEnd,
-                               final Spanned dest,
-                               final int dStart, final int dEnd) {
-        SpannableStringBuilder replacement = null;
-        int rIndex = 0;
-        final int dLength = dest.length();
-        for (int sIndex = sStart; sIndex < sEnd; ++sIndex) {
-            final char c = source.charAt(sIndex);
-            final int dIndex = dStart + (sIndex - sStart);
-            // Restrict characters to those valid in interfaces.
-            // Ensure adding this character does not push the length over the limit.
-            if ((dIndex < Tunnel.NAME_MAX_LENGTH && isAllowed(c)) &&
-                    dLength + (sIndex - sStart) < Tunnel.NAME_MAX_LENGTH) {
-                ++rIndex;
-            } else {
-                if (replacement == null)
-                    replacement = new SpannableStringBuilder(source, sStart, sEnd);
-                replacement.delete(rIndex, rIndex + 1);
-            }
-        }
-        return replacement;
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.kt b/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.kt
new file mode 100644
index 00000000..ab894195
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.kt
@@ -0,0 +1,45 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android.widget
+
+import android.text.InputFilter
+import android.text.SpannableStringBuilder
+import android.text.Spanned
+import com.wireguard.android.backend.Tunnel
+
+/**
+ * InputFilter for entering WireGuard configuration names (Linux interface names).
+ */
+class NameInputFilter : InputFilter {
+    override fun filter(source: CharSequence,
+                        sStart: Int, sEnd: Int,
+                        dest: Spanned,
+                        dStart: Int, dEnd: Int): CharSequence? {
+        var replacement: SpannableStringBuilder? = null
+        var rIndex = 0
+        val dLength = dest.length
+        for (sIndex in sStart until sEnd) {
+            val c = source[sIndex]
+            val dIndex = dStart + (sIndex - sStart)
+            // Restrict characters to those valid in interfaces.
+            // Ensure adding this character does not push the length over the limit.
+            if (dIndex < Tunnel.NAME_MAX_LENGTH && isAllowed(c) &&
+                    dLength + (sIndex - sStart) < Tunnel.NAME_MAX_LENGTH) {
+                ++rIndex
+            } else {
+                if (replacement == null) replacement = SpannableStringBuilder(source, sStart, sEnd)
+                replacement.delete(rIndex, rIndex + 1)
+            }
+        }
+        return replacement
+    }
+
+    companion object {
+        private fun isAllowed(c: Char) = Character.isLetterOrDigit(c) || "_=+.-".indexOf(c) >= 0
+
+        @JvmStatic
+        fun newInstance() = NameInputFilter()
+    }
+}
diff --git a/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.java b/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.java
deleted file mode 100644
index 3cb151af..00000000
--- a/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.java
+++ /dev/null
@@ -1,221 +0,0 @@
-/*
- * Copyright © 2018 The Android Open Source Project
- * Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android.widget;
-
-import android.animation.ObjectAnimator;
-import android.animation.ValueAnimator;
-import android.content.res.ColorStateList;
-import android.graphics.Canvas;
-import android.graphics.ColorFilter;
-import android.graphics.Matrix;
-import android.graphics.Paint;
-import android.graphics.Path;
-import android.graphics.Path.Direction;
-import android.graphics.PixelFormat;
-import android.graphics.PorterDuff.Mode;
-import android.graphics.Rect;
-import android.graphics.RectF;
-import android.graphics.Region;
-import android.graphics.drawable.Drawable;
-import android.os.Build;
-import android.util.FloatProperty;
-
-import com.wireguard.util.NonNullForAll;
-
-import androidx.annotation.ColorInt;
-import androidx.annotation.IntRange;
-import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
-
-@RequiresApi(Build.VERSION_CODES.N)
-@NonNullForAll
-public class SlashDrawable extends Drawable {
-
-    private static final float CENTER_X = 10.65f;
-    private static final float CENTER_Y = 11.869239f;
-    private static final float CORNER_RADIUS = Build.VERSION.SDK_INT < Build.VERSION_CODES.O ? 0f : 1f;
-    // Draw the slash washington-monument style; rotate to no-u-turn style
-    private static final float DEFAULT_ROTATION = -45f;
-    private static final long QS_ANIM_LENGTH = 350;
-    private static final float SCALE = 24f;
-    private static final float SLASH_HEIGHT = 28f;
-    // These values are derived in un-rotated (vertical) orientation
-    private static final float SLASH_WIDTH = 1.8384776f;
-    // Bottom is derived during animation
-    private static final float LEFT = (CENTER_X - (SLASH_WIDTH / 2)) / SCALE;
-    private static final float RIGHT = (CENTER_X + (SLASH_WIDTH / 2)) / SCALE;
-    private static final float TOP = (CENTER_Y - (SLASH_HEIGHT / 2)) / SCALE;
-    private static final FloatProperty mSlashLengthProp = new FloatProperty<SlashDrawable>("slashLength") {
-        @Override
-        public Float get(final SlashDrawable object) {
-            return object.mCurrentSlashLength;
-        }
-
-        @Override
-        public void setValue(final SlashDrawable object, final float value) {
-            object.mCurrentSlashLength = value;
-        }
-    };
-    private final Drawable mDrawable;
-    private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
-    private final Path mPath = new Path();
-    private final RectF mSlashRect = new RectF(0, 0, 0, 0);
-    private boolean mAnimationEnabled = true;
-    // Animate this value on change
-    private float mCurrentSlashLength;
-    private float mRotation;
-    private boolean mSlashed;
-
-    public SlashDrawable(final Drawable d) {
-        mDrawable = d;
-    }
-
-    @SuppressWarnings("deprecation")
-    @Override
-    public void draw(final Canvas canvas) {
-        canvas.save();
-        final Matrix m = new Matrix();
-        final int width = getBounds().width();
-        final int height = getBounds().height();
-        final float radiusX = scale(CORNER_RADIUS, width);
-        final float radiusY = scale(CORNER_RADIUS, height);
-        updateRect(
-                scale(LEFT, width),
-                scale(TOP, height),
-                scale(RIGHT, width),
-                scale(TOP + mCurrentSlashLength, height)
-        );
-
-        mPath.reset();
-        // Draw the slash vertically
-        mPath.addRoundRect(mSlashRect, radiusX, radiusY, Direction.CW);
-        // Rotate -45 + desired rotation
-        m.setRotate(mRotation + DEFAULT_ROTATION, width / 2, height / 2);
-        mPath.transform(m);
-        canvas.drawPath(mPath, mPaint);
-
-        // Rotate back to vertical
-        m.setRotate(-mRotation - DEFAULT_ROTATION, width / 2, height / 2);
-        mPath.transform(m);
-
-        // Draw another rect right next to the first, for clipping
-        m.setTranslate(mSlashRect.width(), 0);
-        mPath.transform(m);
-        mPath.addRoundRect(mSlashRect, 1.0f * width, 1.0f * height, Direction.CW);
-        m.setRotate(mRotation + DEFAULT_ROTATION, width / 2, height / 2);
-        mPath.transform(m);
-
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O)
-            canvas.clipPath(mPath, Region.Op.DIFFERENCE);
-        else
-            canvas.clipOutPath(mPath);
-
-        mDrawable.draw(canvas);
-        canvas.restore();
-    }
-
-    @Override
-    public int getIntrinsicHeight() {
-        return mDrawable.getIntrinsicHeight();
-    }
-
-    @Override
-    public int getIntrinsicWidth() {
-        return mDrawable.getIntrinsicWidth();
-    }
-
-    @SuppressWarnings("deprecation")
-    @Override
-    public int getOpacity() {
-        return PixelFormat.OPAQUE;
-    }
-
-    @Override
-    protected void onBoundsChange(final Rect bounds) {
-        super.onBoundsChange(bounds);
-        mDrawable.setBounds(bounds);
-    }
-
-    private float scale(final float frac, final int width) {
-        return frac * width;
-    }
-
-    @Override
-    public void setAlpha(@IntRange(from = 0, to = 255) final int alpha) {
-        mDrawable.setAlpha(alpha);
-        mPaint.setAlpha(alpha);
-    }
-
-    public void setAnimationEnabled(final boolean enabled) {
-        mAnimationEnabled = enabled;
-    }
-
-    @Override
-    public void setColorFilter(@Nullable final ColorFilter colorFilter) {
-        mDrawable.setColorFilter(colorFilter);
-        mPaint.setColorFilter(colorFilter);
-    }
-
-    private void setDrawableTintList(@Nullable final ColorStateList tint) {
-        mDrawable.setTintList(tint);
-    }
-
-    public void setRotation(final float rotation) {
-        if (mRotation == rotation)
-            return;
-        mRotation = rotation;
-        invalidateSelf();
-    }
-
-    @SuppressWarnings("unchecked")
-    public void setSlashed(final boolean slashed) {
-        if (mSlashed == slashed) return;
-
-        mSlashed = slashed;
-
-        final float end = mSlashed ? SLASH_HEIGHT / SCALE : 0f;
-        final float start = mSlashed ? 0f : SLASH_HEIGHT / SCALE;
-
-        if (mAnimationEnabled) {
-            final ObjectAnimator anim = ObjectAnimator.ofFloat(this, mSlashLengthProp, start, end);
-            anim.addUpdateListener((ValueAnimator valueAnimator) -> invalidateSelf());
-            anim.setDuration(QS_ANIM_LENGTH);
-            anim.start();
-        } else {
-            mCurrentSlashLength = end;
-            invalidateSelf();
-        }
-    }
-
-    @Override
-    public void setTint(@ColorInt final int tintColor) {
-        super.setTint(tintColor);
-        mDrawable.setTint(tintColor);
-        mPaint.setColor(tintColor);
-    }
-
-    @Override
-    public void setTintList(@Nullable final ColorStateList tint) {
-        super.setTintList(tint);
-        setDrawableTintList(tint);
-        mPaint.setColor(tint == null ? 0 : tint.getDefaultColor());
-        invalidateSelf();
-    }
-
-    @Override
-    public void setTintMode(final Mode tintMode) {
-        super.setTintMode(tintMode);
-        mDrawable.setTintMode(tintMode);
-    }
-
-    private void updateRect(final float left, final float top, final float right, final float bottom) {
-        mSlashRect.left = left;
-        mSlashRect.top = top;
-        mSlashRect.right = right;
-        mSlashRect.bottom = bottom;
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.kt b/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.kt
new file mode 100644
index 00000000..a93e35f5
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.kt
@@ -0,0 +1,174 @@
+/*
+ * Copyright © 2018 The Android Open Source Project
+ * Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android.widget
+
+import android.animation.ObjectAnimator
+import android.animation.ValueAnimator
+import android.content.res.ColorStateList
+import android.graphics.*
+import android.graphics.drawable.Drawable
+import android.os.Build
+import android.util.FloatProperty
+import android.util.Property
+import androidx.annotation.ColorInt
+import androidx.annotation.IntRange
+import androidx.annotation.RequiresApi
+
+@RequiresApi(Build.VERSION_CODES.N)
+class SlashDrawable(private val mDrawable: Drawable) : Drawable() {
+    private val mPaint = Paint(Paint.ANTI_ALIAS_FLAG)
+    private val mPath = Path()
+    private val mSlashRect = RectF()
+    private var mAnimationEnabled = true
+    // Animate this value on change
+    private var mCurrentSlashLength = 0f
+    private var mRotation = 0f
+    private var mSlashed = false
+
+    override fun draw(canvas: Canvas) {
+        canvas.save()
+        val m = Matrix()
+        val width = bounds.width()
+        val height = bounds.height()
+        val radiusX = scale(CORNER_RADIUS, width)
+        val radiusY = scale(CORNER_RADIUS, height)
+        updateRect(
+                scale(LEFT, width),
+                scale(TOP, height),
+                scale(RIGHT, width),
+                scale(TOP + mCurrentSlashLength, height)
+        )
+        mPath.reset()
+        // Draw the slash vertically
+        mPath.addRoundRect(mSlashRect, radiusX, radiusY, Path.Direction.CW)
+        // Rotate -45 + desired rotation
+        m.setRotate(mRotation + DEFAULT_ROTATION, width / 2f, height / 2f)
+        mPath.transform(m)
+        canvas.drawPath(mPath, mPaint)
+
+        // Rotate back to vertical
+        m.setRotate(-mRotation - DEFAULT_ROTATION, width / 2f, height / 2f)
+        mPath.transform(m)
+
+        // Draw another rect right next to the first, for clipping
+        m.setTranslate(mSlashRect.width(), 0f)
+        mPath.transform(m)
+        mPath.addRoundRect(mSlashRect, 1f * width, 1f * height, Path.Direction.CW)
+        m.setRotate(mRotation + DEFAULT_ROTATION, width / 2f, height / 2f)
+        mPath.transform(m)
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) canvas.clipPath(mPath, Region.Op.DIFFERENCE) else canvas.clipOutPath(mPath)
+        mDrawable.draw(canvas)
+        canvas.restore()
+    }
+
+    override fun getIntrinsicHeight() = mDrawable.intrinsicHeight
+
+    override fun getIntrinsicWidth() = mDrawable.intrinsicWidth
+
+    override fun getOpacity() = PixelFormat.OPAQUE
+
+    override fun onBoundsChange(bounds: Rect) {
+        super.onBoundsChange(bounds)
+        mDrawable.bounds = bounds
+    }
+
+    private fun scale(frac: Float, width: Int) = frac * width
+
+    override fun setAlpha(@IntRange(from = 0, to = 255) alpha: Int) {
+        mDrawable.alpha = alpha
+        mPaint.alpha = alpha
+    }
+
+    fun setAnimationEnabled(enabled: Boolean) {
+        mAnimationEnabled = enabled
+    }
+
+    override fun setColorFilter(colorFilter: ColorFilter?) {
+        mDrawable.colorFilter = colorFilter
+        mPaint.colorFilter = colorFilter
+    }
+
+    private fun setDrawableTintList(tint: ColorStateList?) {
+        mDrawable.setTintList(tint)
+    }
+
+    fun setRotation(rotation: Float) {
+        if (mRotation == rotation) return
+        mRotation = rotation
+        invalidateSelf()
+    }
+
+    fun setSlashed(slashed: Boolean) {
+        if (mSlashed == slashed) return
+        mSlashed = slashed
+        val end = if (mSlashed) SLASH_HEIGHT / SCALE else 0f
+        val start = if (mSlashed) 0f else SLASH_HEIGHT / SCALE
+        if (mAnimationEnabled) {
+            val anim = ObjectAnimator.ofFloat(this, mSlashLengthProp, start, end)
+            anim.addUpdateListener { _ -> invalidateSelf() }
+            anim.duration = QS_ANIM_LENGTH
+            anim.start()
+        } else {
+            mCurrentSlashLength = end
+            invalidateSelf()
+        }
+    }
+
+    override fun setTint(@ColorInt tintColor: Int) {
+        super.setTint(tintColor)
+        mDrawable.setTint(tintColor)
+        mPaint.color = tintColor
+    }
+
+    override fun setTintList(tint: ColorStateList?) {
+        super.setTintList(tint)
+        setDrawableTintList(tint)
+        mPaint.color = tint?.defaultColor ?: 0
+        invalidateSelf()
+    }
+
+    override fun setTintMode(tintMode: PorterDuff.Mode?) {
+        super.setTintMode(tintMode)
+        mDrawable.setTintMode(tintMode)
+    }
+
+    private fun updateRect(left: Float, top: Float, right: Float, bottom: Float) {
+        mSlashRect.left = left
+        mSlashRect.top = top
+        mSlashRect.right = right
+        mSlashRect.bottom = bottom
+    }
+
+    companion object {
+        private const val CENTER_X = 10.65f
+        private const val CENTER_Y = 11.869239f
+        private val CORNER_RADIUS = if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) 0f else 1f
+
+        // Draw the slash washington-monument style; rotate to no-u-turn style
+        private const val DEFAULT_ROTATION = -45f
+        private const val QS_ANIM_LENGTH: Long = 350
+        private const val SCALE = 24f
+        private const val SLASH_HEIGHT = 28f
+
+        // These values are derived in un-rotated (vertical) orientation
+        private const val SLASH_WIDTH = 1.8384776f
+
+        // Bottom is derived during animation
+        private const val LEFT = (CENTER_X - SLASH_WIDTH / 2) / SCALE
+        private const val RIGHT = (CENTER_X + SLASH_WIDTH / 2) / SCALE
+        private const val TOP = (CENTER_Y - SLASH_HEIGHT / 2) / SCALE
+        private val mSlashLengthProp: FloatProperty<SlashDrawable> = object : FloatProperty<SlashDrawable>("slashLength") {
+            override fun get(obj: SlashDrawable): Float {
+                return obj.mCurrentSlashLength
+            }
+
+            override fun setValue(obj: SlashDrawable, value: Float) {
+                obj.mCurrentSlashLength = value
+            }
+        }
+    }
+
+}
diff --git a/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.java b/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.java
deleted file mode 100644
index a0cf2ac6..00000000
--- a/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.java
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * Copyright © 2013 The Android Open Source Project
- * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.android.widget;
-
-import android.content.Context;
-import android.os.Parcelable;
-import android.util.AttributeSet;
-import android.widget.Switch;
-
-import com.wireguard.util.NonNullForAll;
-
-import androidx.annotation.Nullable;
-
-@NonNullForAll
-public class ToggleSwitch extends Switch {
-    private boolean isRestoringState;
-    @Nullable private OnBeforeCheckedChangeListener listener;
-
-    public ToggleSwitch(final Context context) {
-        this(context, null);
-    }
-
-    @SuppressWarnings({"SameParameterValue", "WeakerAccess"})
-    public ToggleSwitch(final Context context, @Nullable final AttributeSet attrs) {
-        super(context, attrs);
-    }
-
-    @Override
-    public void onRestoreInstanceState(final Parcelable state) {
-        isRestoringState = true;
-        super.onRestoreInstanceState(state);
-        isRestoringState = false;
-    }
-
-    @Override
-    public void setChecked(final boolean checked) {
-        if (checked == isChecked())
-            return;
-        if (isRestoringState || listener == null) {
-            super.setChecked(checked);
-            return;
-        }
-        setEnabled(false);
-        listener.onBeforeCheckedChanged(this, checked);
-    }
-
-    public void setCheckedInternal(final boolean checked) {
-        super.setChecked(checked);
-        setEnabled(true);
-    }
-
-    public void setOnBeforeCheckedChangeListener(final OnBeforeCheckedChangeListener listener) {
-        this.listener = listener;
-    }
-
-    public interface OnBeforeCheckedChangeListener {
-        void onBeforeCheckedChanged(ToggleSwitch toggleSwitch, boolean checked);
-    }
-}
diff --git a/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.kt b/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.kt
new file mode 100644
index 00000000..c97cb934
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.kt
@@ -0,0 +1,44 @@
+/*
+ * Copyright © 2013 The Android Open Source Project
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android.widget
+
+import android.content.Context
+import android.os.Parcelable
+import android.util.AttributeSet
+import android.widget.Switch
+
+class ToggleSwitch @JvmOverloads constructor(context: Context?, attrs: AttributeSet? = null) : Switch(context, attrs) {
+    private var isRestoringState = false
+    private var listener: OnBeforeCheckedChangeListener? = null
+    override fun onRestoreInstanceState(state: Parcelable) {
+        isRestoringState = true
+        super.onRestoreInstanceState(state)
+        isRestoringState = false
+    }
+
+    override fun setChecked(checked: Boolean) {
+        if (checked == isChecked) return
+        if (isRestoringState || listener == null) {
+            super.setChecked(checked)
+            return
+        }
+        isEnabled = false
+        listener!!.onBeforeCheckedChanged(this, checked)
+    }
+
+    fun setCheckedInternal(checked: Boolean) {
+        super.setChecked(checked)
+        isEnabled = true
+    }
+
+    fun setOnBeforeCheckedChangeListener(listener: OnBeforeCheckedChangeListener?) {
+        this.listener = listener
+    }
+
+    interface OnBeforeCheckedChangeListener {
+        fun onBeforeCheckedChanged(toggleSwitch: ToggleSwitch?, checked: Boolean)
+    }
+}