diff --git a/app/src/main/java/io/legado/app/base/BaseViewModel.kt b/app/src/main/java/io/legado/app/base/BaseViewModel.kt
index a54dce392..48394680c 100644
--- a/app/src/main/java/io/legado/app/base/BaseViewModel.kt
+++ b/app/src/main/java/io/legado/app/base/BaseViewModel.kt
@@ -4,6 +4,7 @@ import android.app.Application
 import androidx.lifecycle.AndroidViewModel
 import io.legado.app.help.coroutine.Coroutine
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Deferred
 import kotlinx.coroutines.MainScope
 import kotlinx.coroutines.cancel
 import org.jetbrains.anko.AnkoLogger
@@ -11,10 +12,15 @@ import org.jetbrains.anko.AnkoLogger
 open class BaseViewModel(application: Application) : AndroidViewModel(application), CoroutineScope by MainScope(),
     AnkoLogger {
 
-    fun <T> execute(domain: suspend CoroutineScope.() -> T): Coroutine<T> {
-        return Coroutine.with(this) { domain() }
+    fun <T> execute(block: suspend CoroutineScope.() -> T): Coroutine<T> {
+        return Coroutine.with(this) { block() }
     }
 
+    fun <T> submit(block: suspend CoroutineScope.() -> Deferred<T>): Coroutine<T> {
+        return Coroutine.with(this) { block().await() }
+    }
+
+
     override fun onCleared() {
         super.onCleared()
         cancel()
diff --git a/app/src/main/java/io/legado/app/help/permission/Request.kt b/app/src/main/java/io/legado/app/help/permission/Request.kt
index ccd96741f..c13a84e82 100644
--- a/app/src/main/java/io/legado/app/help/permission/Request.kt
+++ b/app/src/main/java/io/legado/app/help/permission/Request.kt
@@ -127,19 +127,21 @@ internal class Request : OnRequestPermissionsResultCallback {
     private fun showSettingDialog(rationale: CharSequence, cancel: () -> Unit) {
         rationaleDialog?.dismiss()
         source?.context?.let {
-            rationaleDialog = AlertDialog.Builder(it)
-                .setTitle(R.string.dialog_title)
-                .setMessage(rationale)
-                .setPositiveButton(R.string.dialog_setting) { _, _ ->
-                    it.startActivity<PermissionActivity>(
-                        Pair(
-                            PermissionActivity.KEY_INPUT_REQUEST_TYPE,
-                            TYPE_REQUEST_SETTING
+            runCatching {
+                rationaleDialog = AlertDialog.Builder(it)
+                    .setTitle(R.string.dialog_title)
+                    .setMessage(rationale)
+                    .setPositiveButton(R.string.dialog_setting) { _, _ ->
+                        it.startActivity<PermissionActivity>(
+                            Pair(
+                                PermissionActivity.KEY_INPUT_REQUEST_TYPE,
+                                TYPE_REQUEST_SETTING
+                            )
                         )
-                    )
-                }
-                .setNegativeButton(R.string.dialog_cancel) { _, _ -> cancel() }
-                .show()
+                    }
+                    .setNegativeButton(R.string.dialog_cancel) { _, _ -> cancel() }
+                    .show()
+            }
         }
     }
 
diff --git a/app/src/main/java/io/legado/app/ui/search/SearchViewModel.kt b/app/src/main/java/io/legado/app/ui/search/SearchViewModel.kt
index 376a47b76..4d32fb49d 100644
--- a/app/src/main/java/io/legado/app/ui/search/SearchViewModel.kt
+++ b/app/src/main/java/io/legado/app/ui/search/SearchViewModel.kt
@@ -9,34 +9,44 @@ import io.legado.app.data.api.CommonHttpApi
 import io.legado.app.data.entities.SearchBook
 import io.legado.app.help.http.HttpHelper
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+
 
 class SearchViewModel(application: Application) : BaseViewModel(application) {
 
     val searchBooks: LiveData<List<SearchBook>> = MutableLiveData()
 
     fun search(start: (() -> Unit)? = null, finally: (() -> Unit)? = null) {
-        execute {
-            val response: String = HttpHelper.getApiService<CommonHttpApi>(
-                "http://www.baidu.com"
-            ).get("http://www.baidu.com").await()
+        launch {
+            delay(1000L)
 
-            delay(4000L)
 
-            Log.e("TAG1", Thread.currentThread().name)
+            repeat(100) {
+                test(it)
+            }
 
-            response
+        }
+    }
 
+
+    private fun test(index: Int) {
+        submit {
+            val response = HttpHelper.getApiService<CommonHttpApi>(
+                "http://www.baidu.com"
+            ).get("http://www.baidu.com")
+
+            Log.e("TAG", "next: $index")
+
+            response
         }
-            .timeout { 100L }
-            .onErrorReturn { "error return" }
             .onStart {
-                Log.e("TAG!", "start")
+                Log.e("TAG!", "start: $index")
             }
             .onSuccess {
-                Log.e("TAG!", "success: $it")
+                Log.e("TAG!", "success: $index --> $it")
             }
             .onError {
-                Log.e("TAG!", "error: $it")
+                Log.e("TAG!", "error: $index --> $it")
             }
             .onFinally {
                 Log.e("TAG!", "finally")