优化

app/src/main/java/io/legado/app/ui/importbook/ImportBookActivity.kt

@@ -14,10 +14,6 @@ import io.legado.app.base.VMBaseActivity
 import io.legado.app.help.AppConfig
 import io.legado.app.utils.getViewModel
 import kotlinx.android.synthetic.main.activity_import_book.*
-import kotlinx.coroutines.Dispatchers.IO
-import kotlinx.coroutines.Dispatchers.Main
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
 import org.jetbrains.anko.sdk27.listeners.onClick
 import java.io.File
 
@@ -58,10 +54,7 @@ class ImportBookActivity : VMBaseActivity<ImportBookViewModel>(R.layout.activity
 
     private fun initEvent() {
         tv_go_back.onClick {
-            if (subDirs.isNotEmpty()) {
+            goBackDir()
-                subDirs.removeAt(subDirs.lastIndex)
-                upPath()
-            }
         }
         btn_add_book.onClick {
 
@@ -81,9 +74,9 @@ class ImportBookActivity : VMBaseActivity<ImportBookViewModel>(R.layout.activity
     }
 
     @SuppressLint("SetTextI18n")
+    @Synchronized
     private fun upPath() {
         rootDoc?.let { rootDoc ->
-            launch(IO) {
             var path = rootDoc.name.toString() + File.separator
             var doc: DocumentFile? = rootDoc
             for (dirName in subDirs) {
@@ -99,13 +92,10 @@ class ImportBookActivity : VMBaseActivity<ImportBookViewModel>(R.layout.activity
                 }
             }
             docList.sortWith(compareBy({ !it.isDirectory }, { it.name }))
-                withContext(Main) {
             tv_path.text = path
             importBookAdapter.setItems(docList)
         }
     }
-        }
-    }
 
     private fun selectImportFolder() {
         try {
@@ -133,16 +123,25 @@ class ImportBookActivity : VMBaseActivity<ImportBookViewModel>(R.layout.activity
         }
     }
 
+    @Synchronized
     override fun findFolder(dirName: String) {
         subDirs.add(dirName)
         upPath()
     }
 
-    override fun onBackPressed() {
+    @Synchronized
-        if (subDirs.isNotEmpty()) {
+    private fun goBackDir(): Boolean {
+        return if (subDirs.isNotEmpty()) {
             subDirs.removeAt(subDirs.lastIndex)
             upPath()
+            true
         } else {
+            false
+        }
+    }
+
+    override fun onBackPressed() {
+        if (!goBackDir()) {
             super.onBackPressed()
         }
     }