Wie kommuniziere ich mit einem USB-Gerät?
Ich versuche, die USB-Kommunikation als Host einzurichten. Ich folge hier den Beispielenhttp://developer.android.com/guide/topics/usb/host.html aber ich kann das nicht zum Laufen bringen. Hier ist mein Code:
<code>private static final String ACTION_USB_PERMISSION = "com.multitools.andres.LCView"; UsbDevice device; //Pide permisos al usuario para comunicacion con el dispositivo USB private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (ACTION_USB_PERMISSION.equals(action)) { synchronized (this) { UsbDevice device = (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE); if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) { if(device != null){ //call method to set up device communication } } else { Log.d(TAG, "permission denied for device " + device); } } } } }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if(DEBUG) Log.i(TAG, "onCreate() -> MainMenu"); actionBar = getActionBar(); //obtengo el ActionBar actionBar.setDisplayHomeAsUpEnabled(true); //el icono de la aplicacion funciona como boton HOME //Menu setListAdapter(new ArrayAdapter<String>(MainMenu.this, android.R.layout.simple_list_item_1, MenuNames)); //USB if(DEBUG) Log.i(TAG, "Setting UsbManager -> MainMenu"); UsbManager mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE); PendingIntent mPermissionIntent; if(DEBUG) Log.i(TAG, "Setting PermissionIntent -> MainMenu"); mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0); if(DEBUG) Log.i(TAG, "Setting IntentFilter -> MainMenu"); IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION); if(DEBUG) Log.i(TAG, "Setting registerReceiver -> MainMenu"); registerReceiver(mUsbReceiver, filter); if(DEBUG) Log.i(TAG, "Setting requestPermission -> MainMenu"); mUsbManager.requestPermission(device, mPermissionIntent); } </code>
Ich erhalte das Dialogfeld "Schließen erzwingen", wenn ich die Zeile auskommentieremUsbManager.requestPermission(device, mPermissionIntent);
Wenn ich es kommentiere, schaffe ich es nicht, aber es funktioniert nicht. Ich denke, das Problem liegt in:
<code>private static final String ACTION_USB_PERMISSION = "com.multitools.andres.LCView"; </code>
In Googles Beispiel ist es wie folgt:
<code>private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION"; </code>
Aber ich weiß nicht genau, was ich dort hinstellen soll, und ich konnte keine Erklärung dafür finden. Was muss ich da hinstellen oder wo ist mein Fehler? Hier ist der LogCat, den ich bekomme, wenn ich meine Anwendung starte:
<code>04-17 00:57:50.944: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:51.331: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:51.981: I/(1362): onCreate() -> MainMenu 04-17 00:57:52.013: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:52.151: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:52.570: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:52.731: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:53.122: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:53.231: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:53.390: I/(1362): Setting UsbManager -> MainMenu 04-17 00:57:53.451: I/(1362): Setting PermissionIntent -> MainMenu 04-17 00:57:53.470: I/(1362): Setting IntentFilter -> MainMenu 04-17 00:57:53.470: I/(1362): Setting registerReceiver -> MainMenu 04-17 00:57:53.511: I/(1362): Setting requestPermission -> MainMenu 04-17 00:57:53.660: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:53.791: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:54.311: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:54.401: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:54.531: I/(1362): onCreateOptionsMenu() -> MainMenu 04-17 00:57:54.683: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:54.772: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:55.186: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:55.291: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:55.661: I/dalvikvm(1362): threadid=3: reacting to signal 3 04-17 00:57:55.751: I/dalvikvm(1362): Wrote stack traces to '/data/anr/traces.txt' 04-17 00:57:55.791: D/gralloc_goldfish(1362): Emulator without GPU emulation detected. 04-17 01:11:47.323: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:47.720: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:48.124: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:48.291: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:48.452: I/(1459): onCreate() -> MainMenu 04-17 01:11:48.691: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:48.813: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:49.172: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:49.321: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:49.653: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:49.821: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:49.901: I/(1459): Setting UsbManager -> MainMenu 04-17 01:11:49.931: I/(1459): Setting PermissionIntent -> MainMenu 04-17 01:11:50.021: I/(1459): Setting IntentFilter -> MainMenu 04-17 01:11:50.031: I/(1459): Setting registerReceiver -> MainMenu 04-17 01:11:50.051: I/(1459): Setting requestPermission -> MainMenu 04-17 01:11:50.071: D/AndroidRuntime(1459): Shutting down VM 04-17 01:11:50.133: W/dalvikvm(1459): threadid=1: thread exiting with uncaught exception (group=0x409c01f8) 04-17 01:11:50.231: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:50.331: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:50.401: E/AndroidRuntime(1459): FATAL EXCEPTION: main 04-17 01:11:50.401: E/AndroidRuntime(1459): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.multitools.andres/com.multitools.andres.MainMenu}: java.lang.NullPointerException 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.ActivityThread.access$600(ActivityThread.java:123) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.os.Handler.dispatchMessage(Handler.java:99) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.os.Looper.loop(Looper.java:137) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.ActivityThread.main(ActivityThread.java:4424) 04-17 01:11:50.401: E/AndroidRuntime(1459): at java.lang.reflect.Method.invokeNative(Native Method) 04-17 01:11:50.401: E/AndroidRuntime(1459): at java.lang.reflect.Method.invoke(Method.java:511) 04-17 01:11:50.401: E/AndroidRuntime(1459): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 04-17 01:11:50.401: E/AndroidRuntime(1459): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 04-17 01:11:50.401: E/AndroidRuntime(1459): at dalvik.system.NativeStart.main(Native Method) 04-17 01:11:50.401: E/AndroidRuntime(1459): Caused by: java.lang.NullPointerException 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.os.Parcel.readException(Parcel.java:1333) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.os.Parcel.readException(Parcel.java:1281) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.hardware.usb.IUsbManager$Stub$Proxy.requestDevicePermission(IUsbManager.java:535) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.hardware.usb.UsbManager.requestPermission(UsbManager.java:361) 04-17 01:11:50.401: E/AndroidRuntime(1459): at com.multitools.andres.MainMenu.onCreate(MainMenu.java:80) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.Activity.performCreate(Activity.java:4465) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 04-17 01:11:50.401: E/AndroidRuntime(1459): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920) 04-17 01:11:50.401: E/AndroidRuntime(1459): ... 11 more 04-17 01:11:50.751: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:50.851: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:51.331: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:51.403: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' 04-17 01:11:51.774: I/dalvikvm(1459): threadid=3: reacting to signal 3 04-17 01:11:51.961: I/dalvikvm(1459): Wrote stack traces to '/data/anr/traces.txt' </code>
Danke :)