编写NFC标签以执行基本的android任务

Question

Objective :- I want to write nfc tag and associate it with basic android functions like toggle bluetooth, wifi etc. When the android app reads the card it should be able to perform the associated tasks.

I have basic idea of reading and writing nfc tag already. But I need guidance reagrding how can we associate task with nfc tags, as I found no resource on the same. What is the standard & best way to achieve it. I know I can write string on the tag and then latter read it to perform task, but I don't know its the best way or not

This app is already doing this.I need to do something similar.

I have referred and used to https://github.com/nadam/nfc-reader . for reading the tags and https://github.com/balloob/Android-NFC-Tag-Writer for writing tags.

Please help.

Answer 1

When you tap a tag, Android search in all applications, which one could open it.

So you could create tag with a specific "mime-type" and an application which open this kind of tag. An activity is launched because it have "good" filter on this specific "mime-type". You have now to do your action (toogle-wifi, ...) in this activity.

You could create NDEF message with "specific" mime type as this:

String data = "tooggle_wifi";
// New record
NdefRecord appRecord = NdefRecord.createApplicationRecord(context.getPackageName());

// Record with actual data we care about
NdefRecord relayRecord = new NdefRecord(NdefRecord.TNF_MIME_MEDIA,
                                                new String("application/my.specific.tag")
                                                .getBytes(Charset.forName("US-ASCII")),
                                                null, data.getBytes());

Now to catch this kind of tag, in your AndroidManifest, on activity add this filter:

http://developer.android.com/guide/topics/connectivity/nfc/nfc.html#ndef-disc

<intent-filter>
    <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
    <category android:name="android.intent.category.DEFAULT"/>
    <data android:mimeType="application/my.specific.tag" />
</intent-filter>