Library search is now asynchronous

Library will now display progress bar while loading
More optimizations to library search

app/src/main/java/exh/ui/LoadingTools.kt

@@ -0,0 +1,55 @@
+package exh.ui
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import java.util.*
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
+
+typealias LoadingHandle = String
+
+/**
+ * Class used to manage loader UIs
+ */
+class LoaderManager(parentContext: CoroutineContext = EmptyCoroutineContext): CoroutineScope {
+    override val coroutineContext = Dispatchers.Main + parentContext
+
+    private val openLoadingHandles = mutableListOf<LoadingHandle>()
+    var loadingChangeListener: (suspend (newIsLoading: Boolean) -> Unit)? = null
+
+    fun openProgressBar(): LoadingHandle {
+        val (handle, shouldUpdateLoadingStatus) = synchronized(this) {
+            val handle = UUID.randomUUID().toString()
+            openLoadingHandles += handle
+            handle to (openLoadingHandles.size == 1)
+        }
+
+        if(shouldUpdateLoadingStatus) {
+            launch {
+                updateLoadingStatus(true)
+            }
+        }
+
+        return handle
+    }
+
+    @Synchronized
+    fun closeProgressBar(handle: LoadingHandle?) {
+        if(handle == null) return
+
+        val shouldUpdateLoadingStatus = synchronized(this) {
+            openLoadingHandles.remove(handle) && openLoadingHandles.isEmpty()
+        }
+
+        if(shouldUpdateLoadingStatus) {
+            launch {
+                updateLoadingStatus(false)
+            }
+        }
+    }
+
+    private suspend fun updateLoadingStatus(newStatus: Boolean) {
+        loadingChangeListener?.invoke(newStatus)
+    }
+}