Mit dem nativen Zugriff versucht, eine Bluetooth-Funktionalität in Android zu implementieren, aber beim Starten der App auf einem Gerät scheint es, dass die native Zugriffsvariable null ist. Brauchen Sie Hilfe, um herauszufinden, warum es passiert ist und wie Sie es lösen können. DankNative Access von Android kann nicht abgerufen werden
Ein Beispiel für den Einsatz in State Klasse Hinweise
BTNative nativeBT = (BTNative)NativeLookup.create(BTNative.class);
@Override
protected void onMain_ScanButtonAction(Component c, ActionEvent event) {
super.onMain_ScanButtonAction(c, event);
try {
if (nativeBT != null && nativeBT.isSupported()) {
try {
nativeBT.findBT();
nativeBT.openBT();
} catch (Throwable t) {
Dialog.show("Error", "Exception during findBT and openBT access: " + t, "OK", null);
}
}else{
Dialog.show("Error", "Can't get native access", "OK", null);
}
} catch (Throwable t) {
Dialog.show("Error", "Exception during native access: " + t, "OK", null);
}
}
NativeImpl
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;
import android.widget.Toast;
public class BTNativeImpl {
//android built in classes for bluetooth operations
BluetoothAdapter mBluetoothAdapter;
BluetoothSocket mmSocket;
BluetoothDevice mmDevice;
//needed for communication to bluetooth device/network
OutputStream mmOutputStream;
InputStream mmInputStream;
Thread workerThread;
byte[] readBuffer;
int readBufferPosition;
volatile boolean stopWorker;
public void closeBT() {
try {
stopWorker = true;
mmOutputStream.close();
mmInputStream.close();
mmSocket.close();
} catch (Exception e) {
e.printStackTrace();
}
}
//this will send text data to be printed by the bluetooth printer
public void sendData(String param){
try {
// the text typed by the user
param += "\n";
mmOutputStream.write(param.getBytes());
// tell the user data were sent
} catch (Exception e) {
e.printStackTrace();
}
}
//this will find a bluetooth printer device
public void findBT() {
try {
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
Toast.makeText(com.codename1.impl.android.AndroidNativeUtil.getActivity(), "No bluetooth adapter available", Toast.LENGTH_LONG).show();
}
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
com.codename1.impl.android.AndroidNativeUtil.getActivity().startActivityForResult(enableBluetooth, 0);
}
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
for (BluetoothDevice device : pairedDevices) {
if (device.getName().equals("BlueTooth Printer")) {
mmDevice = device;
break;
}
}
}
Toast.makeText(com.codename1.impl.android.AndroidNativeUtil.getActivity(), "Bluetooth device found.", Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
}
}
public void openBT() {
try {
//Standard SerialPortService ID
UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);
mmSocket.connect();
mmOutputStream = mmSocket.getOutputStream();
mmInputStream = mmSocket.getInputStream();
beginListenForData();
Toast.makeText(com.codename1.impl.android.AndroidNativeUtil.getActivity(), "Bluetooth Opened", Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
}
}
public void beginListenForData() {
try {
final Handler handler = new Handler();
//this is the ASCII code for a newline character
final byte delimiter = 10;
stopWorker = false;
readBufferPosition = 0;
readBuffer = new byte[1024];
workerThread = new Thread(new Runnable() {
public void run() {
while (!Thread.currentThread().isInterrupted() && !stopWorker) {
try {
int bytesAvailable = mmInputStream.available();
if (bytesAvailable > 0) {
byte[] packetBytes = new byte[bytesAvailable];
mmInputStream.read(packetBytes);
for (int i = 0; i < bytesAvailable; i++) {
byte b = packetBytes[i];
if (b == delimiter) {
byte[] encodedBytes = new byte[readBufferPosition];
System.arraycopy(readBuffer, 0, encodedBytes, 0, encodedBytes.length);
// specify US-ASCII encoding
final String data = new String(encodedBytes, "US-ASCII");
readBufferPosition = 0;
// tell the user data were sent to bluetooth printer device
handler.post(new Runnable() {
public void run() {
Toast.makeText(com.codename1.impl.android.AndroidNativeUtil.getActivity(), data, Toast.LENGTH_LONG).show();
}
});
} else {
readBuffer[readBufferPosition++] = b;
}
}
}
} catch (IOException ex) {
stopWorker = true;
}
}
}
});
workerThread.start();
} catch (Exception e) {
e.printStackTrace();
}
}
public boolean isSupported() {
return true;
}
}
Ich habe ein paar zusätzliche Erkenntnisse hinzugefügt –
@ JamesH @ ShaiAlmog Ich habe versucht, was Sie vorgeschlagen, indem Sie ** com.codename1.impl.android.AndroidNativeUtil.getActivity() ** und nicht die Erweiterung ** Aktivität **, aber jetzt nichts passiert, wenn ich auf die Schaltfläche zum Verbinden klicke. Ich schaute in den ddms und fand, dass Bluetooth Erlaubnis verweigert wurde (wie in der APP nicht Bluetooth Erlaubnis). Aber ich habe die Berechtigungen auch enthalten. – 4bdu1
@ JamesH @ ShaiAlmog Auch auf die Installation der App sehe ich nicht die Bluetooth-Berechtigungen. – 4bdu1