diff --git a/README.md b/README.md
index d96e23a..2baae77 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Add the dependency to the **Module** gradle file:
 ```gradle
 dependencies {
 	...
-	compile 'com.github.phearme:bt-scan-selector:1.1.6'
+	compile 'com.github.phearme:bt-scan-selector:1.1.7'
 }
 ```
 Enable databinding in the **Module** grade file:
diff --git a/btscanselector/build.gradle b/btscanselector/build.gradle
index ff1db4e..f498485 100644
--- a/btscanselector/build.gradle
+++ b/btscanselector/build.gradle
@@ -7,8 +7,8 @@ android {
     defaultConfig {
         minSdkVersion 14
         targetSdkVersion 26
-        versionCode 19
-        versionName "1.1.6"
+        versionCode 20
+        versionName "1.1.7"
 
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 
diff --git a/btscanselector/src/main/java/com/phearme/btscanselector/BTScanResultItem.java b/btscanselector/src/main/java/com/phearme/btscanselector/BTScanResultItem.java
index 7759691..64d7aca 100644
--- a/btscanselector/src/main/java/com/phearme/btscanselector/BTScanResultItem.java
+++ b/btscanselector/src/main/java/com/phearme/btscanselector/BTScanResultItem.java
@@ -32,19 +32,16 @@ private void updateIconResId() {
             iconResourceId = R.drawable.network_high;
             return;
         }
-        if (rssi <= -50 && rssi > -70) {
+        if (rssi > -70) {
             iconResourceId = R.drawable.network_medium;
             return;
         }
-        if (rssi <= -70 && rssi > -90) {
+        if (rssi > -90) {
             iconResourceId = R.drawable.network_low;
             return;
         }
-        if (rssi <= -90) {
-            iconResourceId = R.drawable.network_no_signal;
-            return;
-        }
-        iconResourceId = R.drawable.network_null;
+        iconResourceId = R.drawable.network_no_signal;
+        //iconResourceId = R.drawable.network_null;
     }
 
     public int getIconResourceId() {
diff --git a/btscanselector/src/main/java/com/phearme/btscanselector/BTScanSelectorDialog.java b/btscanselector/src/main/java/com/phearme/btscanselector/BTScanSelectorDialog.java
index b5126cb..c628820 100644
--- a/btscanselector/src/main/java/com/phearme/btscanselector/BTScanSelectorDialog.java
+++ b/btscanselector/src/main/java/com/phearme/btscanselector/BTScanSelectorDialog.java
@@ -85,13 +85,16 @@ public void setTitle(String title) {
 
     @Override
     public void onDestroy() {
-        if (mAdapter != null) {
+        if (mAdapter != null && getActivity() != null) {
             mAdapter.terminate(getActivity());
         }
         super.onDestroy();
     }
 
     private void bindRecyclerView() {
+        if (getActivity() == null) {
+            return;
+        }
         if (getActivity().checkCallingOrSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
             ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION_PERMISSION);
             return;