NFC开关
权限：android.permission.WRITE_SECURE_SETTINGS接口：android.nfc.NfcAdapter.enable()
权限
Manifest.permission | Android Developers
http://androidxref.com/8.0.0_r4/xref/frameworks/base/core/res/AndroidManifest.xml
接口
http://androidxref.com/8.0.0_r4/xref/frameworks/base/core/java/android/nfc/NfcAdapter.java
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