Kotlin使用Contex报错，初始化失败

代码如下：

private lateinit var context: Context
private fun getSharedPreferences(spFileName: String): SharedPreferences {
            return context.getSharedPreferences(spFileName, Context.MODE_PRIVATE)
        }

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.zego_wb, PID: 7324
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.zego_wb/com.example.zego_wb.activity.LoginActivity}: kotlin.UninitializedPropertyAccessException: lateinit property context has not been initialized
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
     Caused by: kotlin.UninitializedPropertyAccessException: lateinit property context has not been initialized
        at com.example.zego_wb.util.SharedPreferencesUtil$Companion.getSharedPreferences(SharedPreferencesUtil.kt:26)
        at com.example.zego_wb.util.SharedPreferencesUtil$Companion.getLastJoinID(SharedPreferencesUtil.kt:80)
        at com.example.zego_wb.activity.LoginActivity.initView(LoginActivity.kt:35)
        at com.example.zego_wb.activity.LoginActivity.onCreate(LoginActivity.kt:29)