adding some initial gesture handling

app/src/main/kotlin/com/simplemobiletools/launcher/activities/MainActivity.kt

@@ -3,8 +3,10 @@ package com.simplemobiletools.launcher.activities
 import android.content.res.Configuration
 import android.graphics.Color
 import android.os.Bundle
+import android.view.MotionEvent
 import android.widget.FrameLayout
 import com.simplemobiletools.commons.extensions.appLaunched
+import com.simplemobiletools.commons.extensions.realScreenSize
 import com.simplemobiletools.commons.extensions.statusBarHeight
 import com.simplemobiletools.launcher.BuildConfig
 import com.simplemobiletools.launcher.R
@@ -12,6 +14,10 @@ import com.simplemobiletools.launcher.fragments.AllAppsFragment
 import kotlinx.android.synthetic.main.activity_main.*
 
 class MainActivity : SimpleActivity() {
+    private var mTouchDownY = 0
+    private var mScreenHeight = 0
+    private var mCurrentFragmentY = 0
+
     override fun onCreate(savedInstanceState: Bundle?) {
         useDynamicTheme = false
         showTransparentNavigation = true
@@ -21,6 +27,9 @@ class MainActivity : SimpleActivity() {
         appLaunched(BuildConfig.APPLICATION_ID)
         window.setDecorFitsSystemWindows(false)
         (all_apps_fragment as AllAppsFragment).setupFragment(this)
+        mScreenHeight = realScreenSize.y
+        mCurrentFragmentY = mScreenHeight
+        all_apps_fragment.y = mScreenHeight.toFloat()
     }
 
     override fun onResume() {
@@ -34,4 +43,21 @@ class MainActivity : SimpleActivity() {
         super.onConfigurationChanged(newConfig)
         (all_apps_fragment as AllAppsFragment).onConfigurationChanged()
     }
+
+    override fun onTouchEvent(event: MotionEvent): Boolean {
+        when (event.actionMasked) {
+            MotionEvent.ACTION_DOWN -> {
+                mTouchDownY = event.y.toInt()
+                mCurrentFragmentY = all_apps_fragment.y.toInt()
+            }
+
+            MotionEvent.ACTION_MOVE -> {
+                val diffY = mTouchDownY - event.y
+                val newY = mCurrentFragmentY - diffY
+                all_apps_fragment.y = Math.min(Math.max(0f, newY), mScreenHeight.toFloat())
+            }
+        }
+
+        return true
+    }
 }

app/src/main/kotlin/com/simplemobiletools/launcher/fragments/AllAppsFragment.kt

@@ -28,6 +28,7 @@ class AllAppsFragment(context: Context, attributeSet: AttributeSet) : RelativeLa
     fun setupFragment(activity: SimpleActivity) {
         this.activity = activity
         getLaunchers()
+        setBackgroundColor(activity.getProperBackgroundColor())
     }
 
     fun onConfigurationChanged() {

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

@@ -8,4 +8,9 @@
         android:id="@+id/all_apps_fragment"
         layout="@layout/all_apps_fragment" />
 
+    <Button
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/about" />
+
 </RelativeLayout>