本文已参与「新人创作礼」活动，一起开启掘金创作之路。 将apk从android O（targetSdkVersion是23）升级到android R（targetSdkVersion是26）后
从android 11的原生代码里面将opp部分代码扒出来，但是会导致crash
提示
01-27 17:05:59.666 1479 1479 E AndroidRuntime: FATAL EXCEPTION: main
01-27 17:05:59.666 1479 1479 E AndroidRuntime: Process: com.anwsdk.service, PID: 1479
01-27 17:05:59.666 1479 1479 E AndroidRuntime: java.lang.RuntimeException: Unable to create service com.android.bluetooth.opp.BluetoothOppService: java.lang.IllegalStateException: SharedPreferences in credential encrypted storage are not available until after user is unlocked
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.app.ActivityThread.handleCreateService(ActivityThread.java:4204)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.app.ActivityThread.access$1500(ActivityThread.java:237)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1932)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:106)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.os.Looper.loop(Looper.java:223)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:7656)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: Caused by: java.lang.IllegalStateException: SharedPreferences in credential encrypted storage are not available until after user is unlocked
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.app.ContextImpl.getSharedPreferences(ContextImpl.java:494)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.app.ContextImpl.getSharedPreferences(ContextImpl.java:479)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:188)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at com.android.bluetooth.opp.BluetoothOppPreference.init(BluetoothOppPreference.java:87)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at com.android.bluetooth.opp.BluetoothOppPreference.getInstance(BluetoothOppPreference.java:73)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at com.android.bluetooth.opp.BluetoothOppService.onCreate(BluetoothOppService.java:209)
01-27 17:05:59.666 1479 1479 E AndroidRuntime: at android.app.ActivityThread.handleCreateService(ActivityThread.java:4192)
原因：在AndroidO及以上平台上，一个应用使用了SharedPreference的apk，且TargetSdk设置大于等于26，如果在设备刚开机时（用户未解锁），调用getSharedPreferences就会导致crash，从错误提示也可以看出跟user locked有关。源码如下
解决方法：
1、设置targetSdk为小于26。但是我们的程序有很多要26以上的才能用，所以不可行
2、开机处于user locked状态时避免使用SharedPreference，这个也不可行。
3、系统应用可以设置android:defaultToDeviceProtectedStorage=”true”，我们的蓝牙替换了原生的蓝牙，也是系统应用，所以使用这个方案
