优化

app/src/main/java/io/legado/app/utils/HandlerUtils.kt

@@ -11,7 +11,7 @@ import kotlinx.coroutines.launch
 
 /** This main looper cache avoids synchronization overhead when accessed repeatedly. */
 @JvmField
-val mainLooper: Looper = Looper.getMainLooper()!!
+val mainLooper: Looper = Looper.getMainLooper()
 
 @JvmField
 val mainThread: Thread = mainLooper.thread
@@ -22,15 +22,17 @@ val isMainThread: Boolean inline get() = mainThread === Thread.currentThread()
 internal val currentThread: Any?
     inline get() = Thread.currentThread()
 
-@JvmField
-val mainHandler: Handler = if (SDK_INT >= 28) Handler.createAsync(mainLooper) else try {
+val mainHandler: Handler by lazy {
+    if (SDK_INT >= 28) Handler.createAsync(mainLooper) else try {
         Handler::class.java.getDeclaredConstructor(
             Looper::class.java,
             Handler.Callback::class.java,
             Boolean::class.javaPrimitiveType // async
         ).newInstance(mainLooper, null, true)
     } catch (ignored: NoSuchMethodException) {
-    Handler(mainLooper) // Hidden constructor absent. Fall back to non-async constructor.
+        // Hidden constructor absent. Fall back to non-async constructor.
+        Handler(mainLooper)
+    }
 }
 
 fun runOnUI(function: () -> Unit) {