Android 7.0 SystemProperties.get 无法开机

最新推荐文章于 2024-01-05 23:45:00 发布

原创最新推荐文章于 2024-01-05 23:45:00 发布 · 544 阅读

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#android7.0 #SystemProperties.get #No implementation found

本文记录了解决因修改Configuration.java文件导致Android设备无法开机的问题过程。通过调整JNI注册顺序，解决了因SystemProperties.get调用失败引发的错误。

修改了frameworks/base/core/java/android/content/res/Configuration.java

float fontSize = Float.parseFloat(SystemProperties.get("ro.sys.font.default", "1.0"));　后无法开机，打印如下log

No implementation found for 
java.lang.String android.os.SystemProperties.native_get(java.lang.String) 
(tried Java_android_os_SystemProperties_native_1get and Java_android_os_SystemProperties_native_1get__Ljava_lang_String_2

开始以为是平台的代码写的有漏洞，对比了5.1的相关代码，发现代码没有问题；

于是认为是property_service么有启动，于是查了一下system/init下的相关代码，发现也没有问题，并且adb shell getprop 都能正常显示，说明底下的服务没问题，那就只能是jni有问题，查找了一下资料，对照代码，发现问题出在

frameworks/base/core/jni/AndroidRuntime.cpp

static const RegJNIRec gRegJNI[] = {

...

     REG_JNI(register_com_android_internal_os_RuntimeInit),
     REG_JNI(register_android_os_SystemClock),
     REG_JNI(register_android_util_EventLog),
     REG_JNI(register_android_util_Log),
     REG_JNI(register_android_util_MemoryIntArray),
     REG_JNI(register_android_util_PathParser),
     REG_JNI(register_android_app_admin_SecurityLog),

REG_JNI(register_com_mediatek_perfservice_PerfServiceWrapper),

     REG_JNI(register_android_content_AssetManager),
     REG_JNI(register_android_content_StringBlock),
     REG_JNI(register_android_content_XmlBlock),
     REG_JNI(register_android_text_AndroidCharacter),
     REG_JNI(register_android_text_StaticLayout),
     REG_JNI(register_android_text_AndroidBidi),
     REG_JNI(register_android_view_InputDevice),
     REG_JNI(register_android_view_KeyCharacterMap),

REG_JNI(register_android_os_Process),

REG_JNI(register_android_os_SystemProperties), // 　该句注册晚了，导致register_android_content_AssetManager此处调用ｃｏｎｆｉｇｕｒａｔｉｏｎ中调用SystemProperties.get失败，把该句挪到register_android_content_AssetManager即可解决问题

...

}