feat: new ThumbnailProgressBar.kt for animating the loading progress

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/utilities/KThumbnailView.kt

@@ -42,7 +42,7 @@ open class KThumbnailView: FrameLayout {
     private val image by lazy { thumbnail_image }
     private val playOverlay by lazy { play_overlay }
     private val captionIcon by lazy { thumbnail_caption_icon }
-    val loadIndicator: ProgressBar by lazy { thumbnail_load_indicator }
+    val loadIndicator: View by lazy { thumbnail_load_indicator }
     private val transferControls by lazy { ViewUtil.inflateStub<TransferControlView>(this, R.id.transfer_controls_stub) }
 
     private val dimensDelegate = ThumbnailDimensDelegate()

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/utilities/ThumbnailProgressBar.kt

@@ -0,0 +1,69 @@
+package org.thoughtcrime.securesms.conversation.v2.utilities
+
+import android.animation.ValueAnimator
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Interpolator
+import android.graphics.Paint
+import android.graphics.Rect
+import android.os.SystemClock
+import android.util.AttributeSet
+import android.util.Log
+import android.view.View
+import android.view.animation.AccelerateDecelerateInterpolator
+import android.view.animation.Animation
+import android.view.animation.AnimationSet
+import android.view.animation.AnimationUtils
+import androidx.core.content.res.ResourcesCompat
+import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
+import network.loki.messenger.R
+import kotlin.math.sin
+
+class ThumbnailProgressBar: View, ValueAnimator.AnimatorUpdateListener {
+
+    constructor(context: Context) : super(context)
+    constructor(context: Context, attrs: AttributeSet) : super(context, attrs)
+    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
+
+    private val firstX: Double
+    get() = sin(SystemClock.elapsedRealtime() / 300.0) * 1.5
+
+    private val secondX: Double
+    get() = sin(SystemClock.elapsedRealtime() / 300.0 + (Math.PI/4)) * 1.5
+
+    private val paint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+        style = Paint.Style.FILL
+        color = ResourcesCompat.getColor(resources, R.color.accent, null)
+    }
+
+    private val objectRect = Rect()
+    private val drawingRect = Rect()
+
+    override fun onAnimationUpdate(animation: ValueAnimator?) {
+        if (animation == null || !isAttachedToWindow) return
+        invalidate()
+    }
+
+    override fun dispatchDraw(canvas: Canvas?) {
+        if (canvas == null) return
+
+        getDrawingRect(objectRect)
+        drawingRect.set(objectRect)
+
+        val coercedFX = firstX
+        val coercedSX = secondX
+
+        val firstMeasuredX = objectRect.left + (objectRect.width() * coercedFX)
+        val secondMeasuredX = objectRect.left + (objectRect.width() * coercedSX)
+
+        drawingRect.set(
+                (if (firstMeasuredX < secondMeasuredX) firstMeasuredX else secondMeasuredX).toInt(),
+                objectRect.top,
+                (if (firstMeasuredX < secondMeasuredX) secondMeasuredX else firstMeasuredX).toInt(),
+                objectRect.bottom
+        )
+
+        canvas.drawRect(drawingRect, paint)
+        invalidate()
+    }
+}

app/src/main/res/layout/album_thumbnail_view.xml

@@ -35,7 +35,7 @@
             />
         <LinearLayout
             android:id="@+id/albumCellBodyTextParent"
-            android:padding="@dimen/small_spacing"
+            android:paddingHorizontal="@dimen/small_spacing"
             android:layout_width="match_parent"
             android:layout_height="0dp"
             app:layout_constraintBottom_toTopOf="@+id/albumCellBodyTextReadMore"

app/src/main/res/layout/thumbnail_view.xml

@@ -22,14 +22,11 @@
         android:src="@drawable/ic_caption_28"
         android:visibility="gone" />
 
-    <ProgressBar
-        style="@style/Widget.AppCompat.ProgressBar.Horizontal"
+    <org.thoughtcrime.securesms.conversation.v2.utilities.ThumbnailProgressBar
         android:id="@+id/thumbnail_load_indicator"
-        android:progressTint="@color/accent"
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
+        android:layout_height="@dimen/accent_line_thickness"
         android:layout_gravity="bottom"
-        android:indeterminate="true"
         android:visibility="gone"
         tools:visibility="visible" />