diff --git a/app/build.gradle b/app/build.gradle
index 9a931e753..ca951504e 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -18,7 +18,7 @@ def version = "3." + releaseTime()
 def gitCommits = Integer.parseInt('git rev-list --count HEAD'.execute([], project.rootDir).text.trim())
 
 android {
-    compileSdkVersion 29
+    compileSdkVersion 30
     signingConfigs {
         if (project.hasProperty("RELEASE_STORE_FILE")) {
             myConfig {
@@ -34,7 +34,7 @@ android {
     defaultConfig {
         applicationId "io.legado.app"
         minSdkVersion 21
-        targetSdkVersion 29
+        targetSdkVersion 30
         versionCode gitCommits
         versionName version
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
diff --git a/app/src/main/assets/updateLog.md b/app/src/main/assets/updateLog.md
index 4b0715664..fed29cacf 100644
--- a/app/src/main/assets/updateLog.md
+++ b/app/src/main/assets/updateLog.md
@@ -5,6 +5,7 @@
 
 **2020/10/25**
 * 点击书籍分组可显示书籍数量
+* 升级到SDK30
 
 **2020/10/24**
 * 修复选择错误的bug
diff --git a/app/src/main/java/io/legado/app/base/BaseActivity.kt b/app/src/main/java/io/legado/app/base/BaseActivity.kt
index b1d3c76d9..7c5953584 100644
--- a/app/src/main/java/io/legado/app/base/BaseActivity.kt
+++ b/app/src/main/java/io/legado/app/base/BaseActivity.kt
@@ -100,24 +100,19 @@ abstract class BaseActivity(
         } ?: super.onCreateOptionsMenu(menu)
     }
 
-    override fun onMenuOpened(featureId: Int, menu: Menu?): Boolean {
-        menu?.let {
-            menu.applyOpenTint(this)
-            return super.onMenuOpened(featureId, menu)
-        }
-        return true
+    override fun onMenuOpened(featureId: Int, menu: Menu): Boolean {
+        menu.applyOpenTint(this)
+        return super.onMenuOpened(featureId, menu)
     }
 
     open fun onCompatCreateOptionsMenu(menu: Menu) = super.onCreateOptionsMenu(menu)
 
-    final override fun onOptionsItemSelected(item: MenuItem?): Boolean {
-        item?.let {
-            if (it.itemId == android.R.id.home) {
-                supportFinishAfterTransition()
-                return true
-            }
+    final override fun onOptionsItemSelected(item: MenuItem): Boolean {
+        if (item.itemId == android.R.id.home) {
+            supportFinishAfterTransition()
+            return true
         }
-        return item != null && onCompatOptionsItemSelected(item)
+        return onCompatOptionsItemSelected(item)
     }
 
     open fun onCompatOptionsItemSelected(item: MenuItem) = super.onOptionsItemSelected(item)
diff --git a/app/src/main/java/io/legado/app/help/ActivityHelp.kt b/app/src/main/java/io/legado/app/help/ActivityHelp.kt
index 9c9cb0175..b5e1dbe28 100644
--- a/app/src/main/java/io/legado/app/help/ActivityHelp.kt
+++ b/app/src/main/java/io/legado/app/help/ActivityHelp.kt
@@ -104,7 +104,7 @@ object ActivityHelp : Application.ActivityLifecycleCallbacks {
         remove(activity)
     }
 
-    override fun onActivitySaveInstanceState(activity: Activity, outState: Bundle?) {
+    override fun onActivitySaveInstanceState(activity: Activity, outState: Bundle) {
     }
 
     override fun onActivityStopped(activity: Activity) {
diff --git a/app/src/main/java/io/legado/app/help/http/AjaxWebView.kt b/app/src/main/java/io/legado/app/help/http/AjaxWebView.kt
index a12816486..db6dc165b 100644
--- a/app/src/main/java/io/legado/app/help/http/AjaxWebView.kt
+++ b/app/src/main/java/io/legado/app/help/http/AjaxWebView.kt
@@ -64,11 +64,12 @@ class AjaxWebView {
                 webView.webViewClient = HtmlWebViewClient(params, handler)
             }
             when (params.requestMethod) {
-                RequestMethod.POST -> webView.postUrl(params.url, params.postData)
-                RequestMethod.GET -> webView.loadUrl(
-                    params.url,
-                    params.headerMap
-                )
+                RequestMethod.POST -> params.postData?.let {
+                    webView.postUrl(params.url, it)
+                }
+                RequestMethod.GET -> params.headerMap?.let {
+                    webView.loadUrl(params.url, it)
+                }
             }
             return webView
         }
diff --git a/app/src/main/java/io/legado/app/help/permission/RequestManager.kt b/app/src/main/java/io/legado/app/help/permission/RequestManager.kt
index 18bedb800..eb28b9e6c 100644
--- a/app/src/main/java/io/legado/app/help/permission/RequestManager.kt
+++ b/app/src/main/java/io/legado/app/help/permission/RequestManager.kt
@@ -1,6 +1,7 @@
 package io.legado.app.help.permission
 
 import android.os.Handler
+import android.os.Looper
 import java.util.*
 
 internal object RequestManager : OnPermissionsResultCallback {
@@ -8,7 +9,7 @@ internal object RequestManager : OnPermissionsResultCallback {
     private var requests: Stack<Request>? = null
     private var request: Request? = null
 
-    private val handler = Handler()
+    private val handler = Handler(Looper.getMainLooper())
 
     private val requestRunnable = Runnable {
         request?.start()
diff --git a/app/src/main/java/io/legado/app/lib/dialogs/AlertBuilder.kt b/app/src/main/java/io/legado/app/lib/dialogs/AlertBuilder.kt
index b1f0f494d..a938b3584 100644
--- a/app/src/main/java/io/legado/app/lib/dialogs/AlertBuilder.kt
+++ b/app/src/main/java/io/legado/app/lib/dialogs/AlertBuilder.kt
@@ -26,6 +26,7 @@ import android.view.KeyEvent
 import android.view.View
 import androidx.annotation.DrawableRes
 import androidx.annotation.StringRes
+import io.legado.app.R
 import org.jetbrains.anko.internals.AnkoInternals.NO_GETTER
 import kotlin.DeprecationLevel.ERROR
 
@@ -111,7 +112,7 @@ inline fun AlertBuilder<*>.cancelButton(noinline handler: ((dialog: DialogInterf
     negativeButton(android.R.string.cancel, handler)
 
 inline fun AlertBuilder<*>.yesButton(noinline handler: ((dialog: DialogInterface) -> Unit)? = null) =
-    positiveButton(android.R.string.yes, handler)
+    positiveButton(R.string.yes, handler)
 
 inline fun AlertBuilder<*>.noButton(noinline handler: ((dialog: DialogInterface) -> Unit)? = null) =
-    negativeButton(android.R.string.no, handler)
\ No newline at end of file
+    negativeButton(R.string.no, handler)
\ No newline at end of file
diff --git a/app/src/main/java/io/legado/app/ui/association/ImportBookSourceActivity.kt b/app/src/main/java/io/legado/app/ui/association/ImportBookSourceActivity.kt
index c045d0e33..6ff87b095 100644
--- a/app/src/main/java/io/legado/app/ui/association/ImportBookSourceActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/association/ImportBookSourceActivity.kt
@@ -1,5 +1,6 @@
 package io.legado.app.ui.association
 
+import android.annotation.SuppressLint
 import android.content.Context
 import android.content.DialogInterface
 import android.os.Bundle
@@ -169,6 +170,7 @@ class ImportBookSourceActivity : VMBaseActivity<ImportBookSourceViewModel>(
             tool_bar.inflateMenu(R.menu.import_source)
         }
 
+        @SuppressLint("InflateParams")
         override fun onMenuItemClick(item: MenuItem): Boolean {
             when (item.itemId) {
                 R.id.menu_new_group -> {
diff --git a/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt b/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt
index 9d64e43fe..2e4a696ea 100644
--- a/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/book/info/BookInfoActivity.kt
@@ -114,8 +114,8 @@ class BookInfoActivity :
         return super.onCompatOptionsItemSelected(item)
     }
 
-    override fun onMenuOpened(featureId: Int, menu: Menu?): Boolean {
-        menu?.findItem(R.id.menu_can_update)?.isChecked =
+    override fun onMenuOpened(featureId: Int, menu: Menu): Boolean {
+        menu.findItem(R.id.menu_can_update)?.isChecked =
             viewModel.bookData.value?.canUpdate ?: true
         return super.onMenuOpened(featureId, menu)
     }
diff --git a/app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt b/app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt
index 540bb2a05..6939d413f 100644
--- a/app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt
+++ b/app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt
@@ -9,6 +9,7 @@ import android.graphics.drawable.ColorDrawable
 import android.net.Uri
 import android.os.Bundle
 import android.os.Handler
+import android.os.Looper
 import android.view.*
 import android.view.ViewGroup.LayoutParams.WRAP_CONTENT
 import androidx.core.view.get
@@ -92,7 +93,7 @@ class ReadBookActivity : VMBaseActivity<ReadBookViewModel>(R.layout.activity_boo
     override val scope: CoroutineScope get() = this
     override val isInitFinish: Boolean get() = viewModel.isInitFinish
     override val isScroll: Boolean get() = page_view.isScroll
-    private val mHandler = Handler()
+    private val mHandler = Handler(Looper.getMainLooper())
     private val keepScreenRunnable: Runnable =
         Runnable { ReadBookActivityHelp.keepScreenOn(window, false) }
     private val autoPageRunnable: Runnable = Runnable { autoPagePlus() }
diff --git a/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt b/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt
index 7d5b1858a..a28cfabf4 100644
--- a/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt
+++ b/app/src/main/java/io/legado/app/ui/book/search/SearchViewModel.kt
@@ -2,6 +2,7 @@ package io.legado.app.ui.book.search
 
 import android.app.Application
 import android.os.Handler
+import android.os.Looper
 import androidx.lifecycle.MutableLiveData
 import io.legado.app.App
 import io.legado.app.base.BaseViewModel
@@ -15,7 +16,7 @@ import kotlinx.coroutines.isActive
 
 class SearchViewModel(application: Application) : BaseViewModel(application),
     SearchBookModel.CallBack {
-    val handler = Handler()
+    val handler = Handler(Looper.getMainLooper())
     private val searchBookModel = SearchBookModel(this, this)
     var isSearchLiveData = MutableLiveData<Boolean>()
     var searchBookLiveData = MutableLiveData<List<SearchBook>>()
diff --git a/app/src/main/java/io/legado/app/ui/book/toc/BookmarkFragment.kt b/app/src/main/java/io/legado/app/ui/book/toc/BookmarkFragment.kt
index 0f507640c..3b5682f5e 100644
--- a/app/src/main/java/io/legado/app/ui/book/toc/BookmarkFragment.kt
+++ b/app/src/main/java/io/legado/app/ui/book/toc/BookmarkFragment.kt
@@ -3,7 +3,6 @@ package io.legado.app.ui.book.toc
 import android.annotation.SuppressLint
 import android.app.Activity
 import android.content.Intent
-import android.os.AsyncTask
 import android.os.Bundle
 import android.view.View
 import android.widget.EditText
@@ -102,10 +101,8 @@ class BookmarkFragment : VMBaseFragment<ChapterListViewModel>(R.layout.fragment_
                 }
                 yesButton {
                     editText?.text?.toString()?.let { editContent ->
-                        AsyncTask.execute {
-                            bookmark.content = editContent
-                            App.db.bookmarkDao().update(bookmark)
-                        }
+                        bookmark.content = editContent
+                        App.db.bookmarkDao().update(bookmark)
                     }
                 }
                 noButton()
diff --git a/app/src/main/java/io/legado/app/ui/login/SourceLogin.kt b/app/src/main/java/io/legado/app/ui/login/SourceLogin.kt
index 767545d38..dffe03695 100644
--- a/app/src/main/java/io/legado/app/ui/login/SourceLogin.kt
+++ b/app/src/main/java/io/legado/app/ui/login/SourceLogin.kt
@@ -55,7 +55,9 @@ class SourceLogin : BaseActivity(R.layout.activity_source_login) {
                 super.onPageFinished(view, url)
             }
         }
-        web_view.loadUrl(loginUrl)
+        loginUrl?.let {
+            web_view.loadUrl(it)
+        }
     }
 
     override fun onCompatCreateOptionsMenu(menu: Menu): Boolean {
@@ -69,7 +71,9 @@ class SourceLogin : BaseActivity(R.layout.activity_source_login) {
                 if (!checking) {
                     checking = true
                     title_bar.snackbar(R.string.check_host_cookie)
-                    web_view.loadUrl(sourceUrl)
+                    loginUrl?.let {
+                        web_view.loadUrl(it)
+                    }
                 }
             }
         }
diff --git a/app/src/main/java/io/legado/app/utils/ActivityExtensions.kt b/app/src/main/java/io/legado/app/utils/ActivityExtensions.kt
new file mode 100644
index 000000000..656da42d1
--- /dev/null
+++ b/app/src/main/java/io/legado/app/utils/ActivityExtensions.kt
@@ -0,0 +1,2 @@
+package io.legado.app.utils
+