我試圖從NFC標籤讀取數據。如果我使用Play Store的「NfcV-reader」應用程序(由ST Microelectronics,標籤製造商編寫),那麼我可以確認該標籤包含帶有MIME數據的NDEF記錄。 MIME類型是「應用程序/ MyApp的」和MIME有效載荷是「0123」,如下圖所示:Android NFC:正在接收TECH_DISCOVERED,期待NDEF_DISCOVERED
我想我自己的應用程序啓動時這個標籤是由Android的認可。我用我認爲是正確的意圖過濾器創建了該應用程序。這裏的AndroidManifest XML:
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
package="com.dummy.nfc.reader">
<uses-permission android:name="android.permission.NFC" />
<uses-feature android:name="android.hardware.nfc" android:required="true" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".ActivityNfcReader">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.ACTION_NDEF_DISCOVERED"/>
<category android:name="android.intent.category.DEFAULT"/>
<data android:mimeType="application/myapp"/>
</intent-filter>
</activity>
</application>
</manifest>
我已經下載了應用一臺Nexus 6P設備(Android版本6.0.1),將設備設置到主屏幕,並與字符串「NFC」的過濾器開始的logcat 。下面是我得到:
04-11 16:23:33.108 4050 4050 D NativeNfcTag: Connect to a tech with a different handle
04-11 16:23:33.273 4050 3909 D NativeNfcTag: Starting background presence check
04-11 16:23:33.278 918 4148 I ActivityManager: START u0 {flg=0x10008000 cmp=com.android.nfc/.NfcRootActivity (has extras)} from uid 1027 on display 0
04-11 16:23:33.343 918 3469 I ActivityManager: START u0 {act=android.nfc.action.TECH_DISCOVERED cmp=com.google.android.tag/com.android.apps.tag.TagViewer (has extras)} from uid 1027 on display 0
04-11 16:23:35.430 4050 3909 D NativeNfcTag: Tag lost, restarting polling loop
04-11 16:23:35.432 4050 3909 D NfcService: Discovery configuration equal, not updating.
04-11 16:23:35.433 4050 3909 D NativeNfcTag: Stopping background presence check
我的問題是:爲什麼Android的調度「android.nfc.action.TECH_DISCOVERED」當我期待「android.nfc.action.NDEF_DISCOVERED」?
EDIT 1
我使用另一應用中, 「NFC TagInfo」,驗證標記的內容(接收低於第一註釋之後加入更多信息)。掃描的標籤顯示爲NFC TagInfo如下:最後在這裏
是呈現標籤到Android設備的logcat的:
04-12 09:30:48.609 3829 3829 D NativeNfcTag: Connect to a tech with a different handle
04-12 09:30:48.775 3829 10744 D NativeNfcTag: Starting background presence check
04-12 09:30:50.661 917 6053 I ActivityManager: START u0 {cmp=at.mroland.android.apps.nfctaginfo/.TagViewer (has extras)} from uid 10103 on display 0
04-12 09:30:50.834 917 935 I ActivityManager: Displayed at.mroland.android.apps.nfctaginfo/.TagViewer: +160ms
EDIT 2 (在解決問題後用正確的logcat添加正確的logcat)
問題出在intent過濾器上。請參閱下面的接受答案。以下是現在已解決問題的logcat行爲:
04-12 12:14:48.237 3829 3829 D NativeNfcTag: Connect to a tech with a different handle
04-12 12:14:49.371 3829 4052 E BrcmNfcNfa: rw_i93_process_timeout(): retry_count = 1
04-12 12:14:49.422 3829 14236 D NativeNfcTag: Starting background presence check
04-12 12:14:49.424 917 4427 I ActivityManager: START u0 {flg=0x10008000 cmp=com.android.nfc/.NfcRootActivity (has extras)} from uid 1027 on display 0
04-12 12:14:49.457 917 6053 I ActivityManager: START u0 {act=android.nfc.action.NDEF_DISCOVERED typ=application/myapp cmp=com.dummy.nfc.reader/.ActivityNfcReader (has extras)} from uid 1027 on display 0
04-12 12:14:49.553 917 935 I ActivityManager: Displayed com.dummy.nfc.reader/.ActivityNfcReader: +91ms (total +106ms)
你驗證(例如與像NFC TagInfo的應用程序)是Android的實際暴露了'Ndef'標籤技術爲您的設備上的標籤?請注意,由於Type 5 Tag技術最近才由NFC論壇指定,因此並非所有Android設備都支持所有NFC-V標籤上的NDEF。 –
謝謝邁克爾。我已經使用NFC TagInfo應用的屏幕截圖更新了問題。該應用程序建議Android將標籤識別爲NfcV(android.nfc.tech.NfcV)並支持NDEF(android.nfc.tech.Ndef)。 – pfp