adding some stopwatch UI

app/src/main/kotlin/com/simplemobiletools/clock/extensions/Long.kt

@@ -0,0 +1,25 @@
+package com.simplemobiletools.clock.extensions
+
+import java.util.concurrent.TimeUnit
+
+fun Long.formatStopwatchTime(): String {
+    val hours = TimeUnit.MILLISECONDS.toHours(this)
+    val minutes = TimeUnit.MILLISECONDS.toMinutes(this) - TimeUnit.HOURS.toMinutes(hours)
+    val seconds = TimeUnit.MILLISECONDS.toSeconds(this) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(this))
+    val ms = (this % 1000) / 10
+
+    return when {
+        hours > 0 -> {
+            val format = "%02d:%02d:%02d.%02d"
+            String.format(format, hours, minutes, seconds, ms)
+        }
+        minutes > 0 -> {
+            val format = "%02d:%02d.%02d"
+            String.format(format, minutes, seconds, ms)
+        }
+        else -> {
+            val format = "%02d.%02d"
+            String.format(format, seconds, ms)
+        }
+    }
+}

app/src/main/kotlin/com/simplemobiletools/clock/fragments/StopwatchFragment.kt

@@ -1,17 +1,62 @@
 package com.simplemobiletools.clock.fragments
 
+import android.graphics.Color
 import android.os.Bundle
+import android.os.Handler
 import android.support.v4.app.Fragment
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import com.simplemobiletools.clock.R
+import com.simplemobiletools.clock.extensions.config
+import com.simplemobiletools.clock.extensions.formatStopwatchTime
+import com.simplemobiletools.commons.extensions.getAdjustedPrimaryColor
+import com.simplemobiletools.commons.extensions.getColoredDrawableWithColor
+import com.simplemobiletools.commons.extensions.updateTextColors
+import kotlinx.android.synthetic.main.fragment_stopwatch.*
+import kotlinx.android.synthetic.main.fragment_stopwatch.view.*
 
 class StopwatchFragment : Fragment() {
+    private val updateHandler = Handler()
+    private var currMS = 0L
+    private var isRunning = false
+
     lateinit var view: ViewGroup
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
-        view = inflater.inflate(R.layout.fragment_stopwatch, container, false) as ViewGroup
+        view = (inflater.inflate(R.layout.fragment_stopwatch, container, false) as ViewGroup).apply {
+            stopwatch_time.setOnClickListener { togglePlayPause() }
+            stopwatch_play_pause.setOnClickListener { togglePlayPause() }
+        }
         return view
     }
+
+    override fun onResume() {
+        super.onResume()
+        setupStopwatch()
+    }
+
+    private fun setupStopwatch() {
+        stopwatch_time.text = currMS.formatStopwatchTime()
+        setupViews()
+    }
+
+    private fun setupViews() {
+        context!!.apply {
+            updateTextColors(view.stopwatch_fragment)
+            view.stopwatch_play_pause.background = resources.getColoredDrawableWithColor(R.drawable.circle_background_filled, getAdjustedPrimaryColor())
+            updatePlayPauseIcon()
+        }
+    }
+
+    private fun updatePlayPauseIcon() {
+        val drawableId = if (isRunning) R.drawable.ic_pause else R.drawable.ic_play
+        val iconColor = if (context!!.getAdjustedPrimaryColor() == Color.WHITE) Color.BLACK else context!!.config.textColor
+        view.stopwatch_play_pause.setImageDrawable(resources.getColoredDrawableWithColor(drawableId, iconColor))
+    }
+
+    private fun togglePlayPause() {
+        isRunning = !isRunning
+        updatePlayPauseIcon()
+    }
 }