我正在尝试使用输入输出流与Android上的USB通信，因为我在一个活动中使用处理程序，它工作正常，但如果在每个活动中分别使用处理程序它不能正常工作，所以我希望作为所有活动的调解者，在活动中进行共同活动并进行交流，我尝试了类似
的活动public class BasicAccessoryDemo extends Activity implements View.OnClickListener {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button mycontrol, close_command;
mycontrol = (Button) findViewById(R.id.send_command);
mycontrol.setOnClickListener(this);
}
@Override
public void onStart() {
super.onStart();
}
@Override
public void onResume() {
super.onResume();
}
public void onClick(View view) {
switch (view.getId()) {
case R.id.send_command:
byte[] commandPacket = new byte[2];
commandPacket[0] =0x12;
commandPacket[1] =0x34;
Usb_Communciation.Send_message(commandPacket);
break;
}
}
}
和另一个持有处理程序的类是
public class Usb_Communciation extends Activity{
public final static int USBAccessoryWhat = 0;
public int firmwareProtocol = 0;
public static USBAccessoryManager accessoryManager;
public static String TAG = "MICROCHIP";
public static final int APP_CONNECT = (int)0xAE;
public boolean deviceAttached = false;
public void onCreate(Bundle savedInstanceState) {
accessoryManager = new USBAccessoryManager(handler, USBAccessoryWhat);
//accessoryManager.enable(this, getIntent());
}
public static void Send_message(byte[] data) {
try{
accessoryManager.write(data);
}catch (Exception e){
Log.d(TAG,
"USBAccessoryManager:write():IOException: arasu "
+ e.toString());
e.printStackTrace();
}
}
public Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
byte[] commandPacket = new byte[64];
byte[] WriteValue = new byte[2];
switch(msg.what)
{
case USBAccessoryWhat:
boolean StopReading = true;
int count = 0;
switch(((USBAccessoryManagerMessage)msg.obj).type)
{
case READ:
if(accessoryManager.isConnected() == false) {
return;
}
while(true) {
if (accessoryManager.available() < 2) {
break;
}
}
break;
case READY:
String version = ((USBAccessoryManagerMessage)msg.obj).accessory.getVersion();
firmwareProtocol = getFirmwareProtocol(version);
switch(firmwareProtocol){
case 1:
deviceAttached = true;
break;
case 2:
deviceAttached = true;
commandPacket[0] = (byte) APP_CONNECT;
commandPacket[1] = 0;
accessoryManager.write(commandPacket);
Log.d(TAG,"connect message sent.");
break;
}
break;
}
break;
} //switch
} //handleMessage
}; //handler
public int getFirmwareProtocol(String version) {
String major = "0";
int positionOfDot;
positionOfDot = version.indexOf('.');
if(positionOfDot != -1) {
major = version.substring(0, positionOfDot);
}
return new Integer(major).intValue();
}
}
答案 0 :(得分：1)
在这种情况下，我们使用IntentService。定义IntentService的位置，该类是在收到操作时将在后台运行的类。然后你可以处理输入输出流（在后台!!这就是我们想要的），然后使用BroadcastReceiver向你的活动发送广播。
答案 1 :(得分：1)
您正在使用类似普通java类的活动类，我看到第二个活动没有任何视图文件。您可以使用构造函数创建一个名为UsbCommunication的普通类，并在您的活动中对其进行初始化，如下所示：
public class Usb_Communciation {
public final static int USBAccessoryWhat = 0;
public int firmwareProtocol = 0;
public static USBAccessoryManager accessoryManager;
public static String TAG = "MICROCHIP";
public static final int APP_CONNECT = (int)0xAE;
public boolean deviceAttached = false;
public Usb_Communciation (/*Pass neccesary parameters here from activity*/) {
accessoryManager = new USBAccessoryManager(handler, USBAccessoryWhat);
}
public void Send_message(byte[] data) {
try{
accessoryManager.write(data);
}catch (Exception e){
Log.d(TAG,
"USBAccessoryManager:write():IOException: arasu "
+ e.toString());
e.printStackTrace();
}
}
public Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
byte[] commandPacket = new byte[64];
byte[] WriteValue = new byte[2];
switch(msg.what)
{
case USBAccessoryWhat:
boolean StopReading = true;
int count = 0;
switch(((USBAccessoryManagerMessage)msg.obj).type)
{
case READ:
if(accessoryManager.isConnected() == false) {
return;
}
while(true) {
if (accessoryManager.available() < 2) {
break;
}
}
break;
case READY:
String version = ((USBAccessoryManagerMessage)msg.obj).accessory.getVersion();
firmwareProtocol = getFirmwareProtocol(version);
switch(firmwareProtocol){
case 1:
deviceAttached = true;
break;
case 2:
deviceAttached = true;
commandPacket[0] = (byte) APP_CONNECT;
commandPacket[1] = 0;
accessoryManager.write(commandPacket);
Log.d(TAG,"connect message sent.");
break;
}
break;
}
break;
} //switch
} //handleMessage
}; //handler
public int getFirmwareProtocol(String version) {
String major = "0";
int positionOfDot;
positionOfDot = version.indexOf('.');
if(positionOfDot != -1) {
major = version.substring(0, positionOfDot);
}
return new Integer(major).intValue();
}
在您的活动中调用函数：
public void onClick(View view) {
switch (view.getId()) {
case R.id.send_command:
byte[] commandPacket = new byte[2];
commandPacket[0] =0x12;
commandPacket[1] =0x34;
Usb_Communication usbCom = new Usb_Communication();
usbCom.Send_message(commandPacket);
break;
}
}
答案 2 :(得分：1)
您可以在Application类中创建一个Handler。
public class YourApp extends Application {
private Handler handler;
@Override
public void onCreate() {
super.onCreate();
handler = new Handler(Looper.getMainLooper());
}
public Handler getHandler() {
return handler;
}
}
然后你可以从其他组件中获取一个处理程序，例如来自Activity：
((YourApp)getApplication()).getHandler();
不要忘记在清单文件中设置应用程序名称。
<application
android:name=".YourApp"
....>