External password keyboard and identity card information interaction method based on Android platform

The invention discloses an external password keyboard and identity card information interaction method based on an Android platform, which comprises a POS machine based on the Android platform, an NFC unit and an external password keyboard, and comprises the following steps: S01, establishing an interaction thread to drive the NFC unit to carry out magnetic card identification work; s02, the working state of the NFC unit is judged, and a judgment result is generated; s03, obtaining a judgment result, and initializing the NFC unit when the NFC unit is in a non-information interaction state; s04, the NFC unit enters a card searching state, when card searching succeeds, an apdu random number is taken, then apdu communication is started, and meanwhile, the NFC unit sends read magnetic card information to the POS machine and completes response interaction; s05, the apdu communication condition is judged, and in combination with the read magnetic card data, the onTagDiscovery callback of the NFC unit is executed; a