android phone sim card status issues related to access to

Hello everyone, ask you a question, android phone sim card status is achieved by TelephonyManager class getSimState () implementation, getSimState () call SystemProperties.get () method, I ask you SystemProperties.java in nativa_get (String key) method specifically how to achieve? Thank you enlighten me!
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why should care about this way to do that?
concrete realization in the native layer, you can look the corresponding jni file: frameworks \ base \ core \ jni \ android_os_SystemProperties.cpp, method_table given function mapping table, native_get corresponding SystemProperties_getS ()



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Thank you, I look at
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continue to wait for you to enlighten me!
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Haotie to the top but there are still word limit