diff --git a/README.md b/README.md
index d58171b..7edab2d 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 ![](https://img.shields.io/badge/language-Java%20&%20kotlin-orange.svg)
 ![](https://img.shields.io/hexpm/l/plug.svg)
 
-最近更新 2020.12.26
+最近更新 2020.12.29
 
 ### How to use
 
@@ -22,13 +22,13 @@ allprojects {
 ```
 dependencies {
     //kotlin 版本
-    implementation 'com.github.yechaoa.YUtils:yutilskt:3.1.4'
+    implementation 'com.github.yechaoa.YUtils:yutilskt:3.1.5'
 
     //java 版本
-    implementation 'com.github.yechaoa.YUtils:yutils:3.1.4'
+    implementation 'com.github.yechaoa.YUtils:yutils:3.1.5'
 
     //kotlin && java 版本
-    implementation 'com.github.yechaoa:YUtils:3.1.4'
+    implementation 'com.github.yechaoa:YUtils:3.1.5'
 }
 ```
 
@@ -39,7 +39,8 @@ dependencies {
 ```
 //初始化
 YUtils.init(this);
-//设置打印开关（可选，默认false）
+
+//打印开关（可选，默认false不打印）
 LogUtil.setIsLog(true);
 ```
 
@@ -75,6 +76,7 @@ LogUtil.setIsLog(true);
 
 * void closeSoftKeyboard()<br>关闭软键盘
 
+* Boolean hasSim()<br>是否有sim卡 即设备是否可以拨打电话等
  
 > ## 2.ToastUtil（任意线程，不重复显示，可取消）.
 
@@ -224,6 +226,10 @@ like this
  
 ## 更新记录
 
+#### 3.1.5（2020-12-29）
+- 初始化校验
+- YUtils新增sim卡判断
+
 #### 3.1.4（2020-12-26）
 - SpUtil优化
 
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 57e7527..dac865d 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -5,7 +5,7 @@
     <application
         android:name=".App"
         android:allowBackup="true"
-        android:icon="@mipmap/ic_launcher"
+        android:icon="@mipmap/ic_logo"
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
diff --git a/app/src/main/java/com/yechaoa/app/MainActivity.kt b/app/src/main/java/com/yechaoa/app/MainActivity.kt
index 3d261f7..64f769a 100644
--- a/app/src/main/java/com/yechaoa/app/MainActivity.kt
+++ b/app/src/main/java/com/yechaoa/app/MainActivity.kt
@@ -53,7 +53,13 @@ class MainActivity : AppCompatActivity() {
 //        ActivityUtil.start(MainActivity::class.java)
 //        ActivityUtil.finish(this)
 
-        LogUtil.i("" + DisplayUtil.getStatusBarHeight() + "---" + DisplayUtil.getScreenHeight())
-        LogUtil.i("" + DisplayUtil.getActionBarHeight() + "---" + DisplayUtil.getNavBarHeight())
+        btn_display.setOnClickListener {
+            LogUtil.i("" + DisplayUtil.getStatusBarHeight() + "---" + DisplayUtil.getScreenHeight())
+            LogUtil.i("" + DisplayUtil.getActionBarHeight() + "---" + DisplayUtil.getNavBarHeight())
+        }
+
+        btn_sim.setOnClickListener {
+            ToastUtil.show(if (YUtils.hasSim()) "有sim卡" else "无sim卡")
+        }
     }
 }
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index d49e3ae..b2f180f 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -1,64 +1,59 @@
 <?xml version="1.0" encoding="utf-8"?>
-<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
+    android:gravity="center"
+    android:orientation="vertical"
     tools:context=".MainActivity">
 
     <TextView
         android:id="@+id/text_view"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="Hello World!"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        android:text="Hello World!" />
 
     <Button
         android:id="@+id/button"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="存StringSet"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/text_view" />
+        android:text="存StringSet" />
 
     <Button
         android:id="@+id/button2"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="读StringSet"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/button" />
+        android:text="读StringSet" />
 
     <Button
         android:id="@+id/showLoading"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="showLoading"
-        app:layout_constraintEnd_toEndOf="@+id/button2"
-        app:layout_constraintStart_toStartOf="@+id/button2"
-        app:layout_constraintTop_toBottomOf="@+id/button2" />
+        android:text="showLoading" />
 
     <Button
         android:id="@+id/hideLoading"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginTop="8dp"
-        android:text="hideLoading"
-        app:layout_constraintEnd_toEndOf="@+id/showLoading"
-        app:layout_constraintStart_toStartOf="@+id/showLoading"
-        app:layout_constraintTop_toBottomOf="@+id/showLoading" />
+        android:text="hideLoading" />
 
     <Button
         android:id="@+id/btn_log"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="打印log"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        android:text="打印log" />
 
-</android.support.constraint.ConstraintLayout>
\ No newline at end of file
+    <Button
+        android:id="@+id/btn_display"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="打印屏幕宽高" />
+
+    <Button
+        android:id="@+id/btn_sim"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="是否有sim卡" />
+
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/mipmap-xxhdpi/ic_logo.png b/app/src/main/res/mipmap-xxhdpi/ic_logo.png
new file mode 100644
index 0000000..a5ae03f
Binary files /dev/null and b/app/src/main/res/mipmap-xxhdpi/ic_logo.png differ
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index b77ea73..6c21464 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1,5 +1,5 @@
 <resources>
-    <string name="app_name">app</string>
+    <string name="app_name">YUtils</string>
 
     <string name="large_text">
         "Material is the metaphor.\n\n"
diff --git a/yutils/src/main/java/com/yechaoa/yutils/YUtils.java b/yutils/src/main/java/com/yechaoa/yutils/YUtils.java
index cbdefbc..5905065 100644
--- a/yutils/src/main/java/com/yechaoa/yutils/YUtils.java
+++ b/yutils/src/main/java/com/yechaoa/yutils/YUtils.java
@@ -8,6 +8,7 @@
 import android.content.Context;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
+import android.telephony.TelephonyManager;
 import android.text.Spannable;
 import android.text.SpannableString;
 import android.text.style.ForegroundColorSpan;
@@ -36,7 +37,7 @@ public class YUtils {
 
     private static Toast toast;
     private static ProgressDialog progressDialog;
-    private static Application mApp;
+    private static Application mApp = null;
 
     /**
      * 使用init()即可
@@ -62,7 +63,11 @@ public static Application getApplication() {
     }
 
     public static Application getApp() {
-        return mApp;
+        if (null == mApp) {
+            throw new NullPointerException("YUtils未在Application中初始化");
+        } else {
+            return mApp;
+        }
     }
 
     /**
@@ -267,4 +272,18 @@ public static void closeSoftKeyboard() {
         inputManger.hideSoftInputFromWindow(ActivityUtil.getCurrentActivity().getWindow().getDecorView().getWindowToken(), 0);
     }
 
+    /**
+     * 是否有sim卡 即设备是否可以拨打电话等
+     */
+    public static Boolean hasSim() {
+        TelephonyManager telephonyManager = (TelephonyManager) getApp().getSystemService(Context.TELEPHONY_SERVICE);
+        boolean result = true;
+        switch (telephonyManager.getSimState()) {
+            case TelephonyManager.SIM_STATE_ABSENT:
+            case TelephonyManager.SIM_STATE_UNKNOWN:
+                result = false;
+                break;
+        }
+        return result;
+    }
 }
diff --git a/yutilskt/src/main/java/com/yechaoa/yutilskt/YUtils.kt b/yutilskt/src/main/java/com/yechaoa/yutilskt/YUtils.kt
index 3c4617d..a9f03e3 100644
--- a/yutilskt/src/main/java/com/yechaoa/yutilskt/YUtils.kt
+++ b/yutilskt/src/main/java/com/yechaoa/yutilskt/YUtils.kt
@@ -6,6 +6,7 @@ import android.content.ClipData
 import android.content.ClipboardManager
 import android.content.Context
 import android.content.pm.PackageManager
+import android.telephony.TelephonyManager
 import android.text.Spannable
 import android.text.SpannableString
 import android.text.style.ForegroundColorSpan
@@ -50,7 +51,11 @@ object YUtils {
     }
 
     fun getApp(): Application {
-        return mApp
+        if (this::mApp.isInitialized) {
+            return mApp
+        } else {
+            throw UninitializedPropertyAccessException("YUtils未在Application中初始化")
+        }
     }
 
     /**
@@ -234,5 +239,16 @@ object YUtils {
         inputManger.hideSoftInputFromWindow(ActivityUtil.currentActivity!!.window.decorView.windowToken, 0)
     }
 
-
+    /**
+     * 是否有sim卡 即设备是否可以拨打电话等
+     */
+    fun hasSim(): Boolean {
+        val telephonyManager = getApp().getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
+        var result = true
+        when (telephonyManager.simState) {
+            TelephonyManager.SIM_STATE_ABSENT -> result = false
+            TelephonyManager.SIM_STATE_UNKNOWN -> result = false
+        }
+        return result
+    }
 }