问题
I am creating an android application that consists of a serial communication.I am getting an error called java.lang.ArrayIndexOutOfBoundsException: length=1; index=1 please tell me how to fix it
This is my usb driver:
public class UsbDriver {
private final Context mApplicationContext;
private final UsbManager mUsbManager;
@SuppressWarnings("unused")
private final UsbConnectionHandler mConnectionHandler;
private final int VID;
private final int PID;
protected static final String ACTION_USB_PERMISSION = "ch.serverbox.android.USB";
public static int Device_Exception;
public static UsbDevice Device_Details;
public static UsbEndpoint Data_In_End_Point = null;
public static UsbEndpoint Data_Out_End_Point = null;
public static UsbDeviceConnection USB_Device_Connection;
public UsbDriver(Activity parentActivity,UsbConnectionHandler connectionHandler, int vid, int pid) {
mApplicationContext = parentActivity.getApplicationContext();
mConnectionHandler = connectionHandler;
mUsbManager = (UsbManager) mApplicationContext.getSystemService(Context.USB_SERVICE);
VID = 1027;
PID = 24577;
Device_Exception = 0;
// init();
Check_Devices();
}
private void Check_Devices() {
@SuppressWarnings("unused")
int j=0;
HashMap<String, UsbDevice> devlist = mUsbManager.getDeviceList();
Iterator<UsbDevice> deviter = devlist.values().iterator();
Device_Details = null;
if (devlist.size() != 0) {
while (deviter.hasNext()) {
Device_Details = deviter.next();
if (Device_Details.getVendorId() == VID && Device_Details.getProductId() == PID){
if (!mUsbManager.hasPermission(Device_Details)){
onPermissionDenied(Device_Details);
} else {
UsbDeviceConnection conn = mUsbManager.openDevice(Device_Details);
if (!conn.claimInterface(Device_Details.getInterface(1), true)){
return;
}
conn.controlTransfer(0x21, 34, 0, 0, null, 0, 0);
conn.controlTransfer(0x21, 32, 0, 0,new byte[] { (byte) 0x80, 0x25 , 0x00, 0x00,0x00, 0x00, 0x08 }, 7, 0);
USB_Device_Connection=conn;
Data_In_End_Point = null;
Data_Out_End_Point = null;
UsbInterface usbIf = Device_Details.getInterface(1);
for (int i = 0; i < usbIf.getEndpointCount(); i++) {
if (usbIf.getEndpoint(i).getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
if (usbIf.getEndpoint(i).getDirection() == UsbConstants.USB_DIR_IN)
Data_In_End_Point = usbIf.getEndpoint(i);
else
Data_Out_End_Point = usbIf.getEndpoint(i);
}
}
if (Data_In_End_Point == null || Data_Out_End_Point == null)
Device_Exception = 2;
}
break;
}j++;
}
if (Device_Details == null) {
Device_Exception = 3;
return;
}
}
else {
Device_Exception = 1;
return;
}
}
public void onPermissionDenied(UsbDevice d) {
UsbManager usbman = (UsbManager) mApplicationContext.getSystemService(Context.USB_SERVICE);
PendingIntent pi = PendingIntent.getBroadcast(mApplicationContext, 0, new Intent(ACTION_USB_PERMISSION), 0);
mApplicationContext.registerReceiver(mPermissionReceiver,new IntentFilter(ACTION_USB_PERMISSION));
usbman.requestPermission(d, pi);
}
private class PermissionReceiver extends BroadcastReceiver {
private final IPermissionListener mPermissionListener;
public PermissionReceiver(IPermissionListener permissionListener){
mPermissionListener = permissionListener;
}
@Override
public void onReceive(Context context, Intent intent) {
mApplicationContext.unregisterReceiver(this);
if (intent.getAction().equals(ACTION_USB_PERMISSION)) {
if (!intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
mPermissionListener.onPermissionDenied((UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE));
} else {
l("Permission granted");
UsbDevice dev = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (dev != null){
if (dev.getVendorId() == VID && dev.getProductId() == PID) {
Check_Devices() ;
}
}else{
e("device not present!");
}
}
}
}
}
private BroadcastReceiver mPermissionReceiver = new PermissionReceiver(new IPermissionListener() {
@Override
public void onPermissionDenied(UsbDevice d) {
l("Permission denied on " + d.getDeviceId());
}
});
private static interface IPermissionListener {
void onPermissionDenied(UsbDevice d);
}
public final static String TAG = "USBController";
private void l(Object msg) {
Log.d(TAG, ">==<" + msg.toString() + " >==<");
}
private void e(Object msg) {
Log.e(TAG, ">==< " + msg.toString() + " >==<");
}
}
This is my usb connection handler
public interface UsbConnectionHandler {
void onUsbStopped();
void onErrorLooperRunningAlready();
void onDeviceNotFound();
}
This is my main activity:
public class MainActivity extends Activity {
EditText communication_data;
Button send;
public static final int targetVendorID = 1027;
public static final int targetProductID = 24577;
public UsbManager manager;
public UsbDeviceConnection usbDeviceConnection;
public UsbInterface usbInterfaceFound = null;
public UsbEndpoint endpointOut = null;
public UsbEndpoint endpointIn = null;
public UsbDevice usbdevice,device_details;
public UsbEndpoint listusbendpoint;
private static final int VID = 1027;
private static final int PID = 24577;
@SuppressWarnings("unused")
private static UsbDriver Usb_Driver_class;
ActionBar actionbar;
UsbConnectionHandler connectionHandler;
public static UsbDriver USB_Driver_Child;
public static boolean Communication_Failed,Frame_Ok,Total_Frame_Decoded;
static byte[] Communication_Byte;
HashMap<String, UsbDevice> devicelist= null;
static byte[] sample;
static boolean Communication_Ok;
static int Sequence_No,Response_Time;
Thread Receive;
ByteBuffer buffer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//communication_data = (EditText)findViewById(R.id.editText_comm);
send = (Button)findViewById(R.id.button1_sendin);
send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Communication_Byte=new byte[1];
if(Check_Devices_Available()==true) {
int Packet_Size = USB_Driver_Child.Data_In_End_Point.getMaxPacketSize();
Toast.makeText(MainActivity.this,""+Packet_Size, Toast.LENGTH_LONG).show();
Receive.start();
Communication_Ok=false;
for(int i=0;(i<5 && Communication_Ok!=true);i++)
Send_Communication_Check_Command();
if(Communication_Ok)
Toast.makeText(MainActivity.this, "Communication Successfully Established", 1000).show();
else
Toast.makeText(MainActivity.this, "Communication Failure", 10000).show();
}
}
private boolean Check_Devices_Available() {
Usb_Driver_class = new UsbDriver(MainActivity.this, connectionHandler, VID, PID);
if(USB_Driver_Child.Device_Exception==0){
if(USB_Driver_Child.USB_Device_Connection==null || USB_Driver_Child.Data_Out_End_Point==null)
return false;
Toast.makeText(MainActivity.this,"Device Found", 1000).show();
return true;
}else if(USB_Driver_Child.Device_Exception==1){
Toast.makeText(MainActivity.this,"No Devices Attached ", Toast.LENGTH_LONG).show();
return false;
}else if(USB_Driver_Child.Device_Exception==2){
Toast.makeText(MainActivity.this,"Device Found,But No End Points", Toast.LENGTH_LONG).show();
return false;
}else if(USB_Driver_Child.Device_Exception==3){
Toast.makeText(MainActivity.this,"Unable to Open Device", Toast.LENGTH_LONG).show();
return false;
}
return false;
}
Thread Receive = new Thread(new Runnable(){
@SuppressWarnings("unused")
@Override
public void run() {
Sequence_No=0;
buffer = ByteBuffer.allocate(64);
sample = new byte[64];
int Frame_Size;
UsbRequest request = new UsbRequest();
int i,j;
byte [] datarx=new byte[1];
char q;
while (true) {
request.initialize(UsbDriver.USB_Device_Connection, UsbDriver.Data_In_End_Point);
request.queue(buffer, 64);
if (UsbDriver.USB_Device_Connection.requestWait() == request) {
sample=buffer.array();
for(i=0;i<64;i++){
if(sample[i]=='&'){
Communication_Ok=true;
break;
}else if(sample[i]==0x03){
if(sample[0]==0x02)
//Frame_Ok=true;
break;
}
}
if(Frame_Ok==true){
//Frame_Ok=false;
//if(sample[1]==1)
//Coil_No=1;
//else
//Coil_No=2;
//Response_Time= (int)(((sample[2]&0x00FF)<<8) + (sample[3]&0x00FF));
//Total_Frame_Decoded=true;
//sample = null;
}
}
}
}
});
private void Send_Communication_Check_Command() {
long i,j;
Communication_Byte[0]='&';
UsbDriver.USB_Device_Connection.bulkTransfer(UsbDriver.Data_Out_End_Point,Communication_Byte, 1, 0);
for(i=0;(i<1000 && Communication_Ok!=true) ;i++)
for(j=0;(j<1000 && Communication_Ok!=true);j++);
}
});
}
}
This is my logcat:
E/AndroidRuntime(2452): FATAL EXCEPTION: main
E/AndroidRuntime(2452): java.lang.ArrayIndexOutOfBoundsException: length=1; index=1
E/AndroidRuntime(2452): at android.hardware.usb.UsbDevice.getInterface(UsbDevice.java:155)
E/AndroidRuntime(2452): at com.developer.milancomm.UsbDriver.Check_Devices(UsbDriver.java:74)
E/AndroidRuntime(2452): at com.developer.milancomm.UsbDriver.<init>(UsbDriver.java:48)
E/AndroidRuntime(2452): at com.developer.milancomm.MainActivity$1.Check_Devices_Available(MainActivity.java:86)
E/AndroidRuntime(2452): at com.developer.milancomm.MainActivity$1.onClick(MainActivity.java:63)
E/AndroidRuntime(2452): at android.view.View.performClick(View.java:4240)
E/AndroidRuntime(2452): at android.view.View$PerformClick.run(View.java:17721)
E/AndroidRuntime(2452): at android.os.Handler.handleCallback(Handler.java:730)
E/AndroidRuntime(2452): at android.os.Handler.dispatchMessage(Handler.java:92)
E/AndroidRuntime(2452): at android.os.Looper.loop(Looper.java:137)
E/AndroidRuntime(2452): at android.app.ActivityThread.main(ActivityThread.java:5103)
E/AndroidRuntime(2452): at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(2452): at java.lang.reflect.Method.invoke(Method.java:525)
E/AndroidRuntime(2452): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
E/AndroidRuntime(2452): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
E/AndroidRuntime(2452): at dalvik.system.NativeStart.main(Native Method)
回答1:
An Array length of 1 means that only the index 0 exist, because in java array indexes start with 0!
Or in other words the Boundaries of an Array are Array.length -1
回答2:
length = 1 means that the array has only 1 element in it, and java is zero based numbering (which means that indexing an array starts from 0 not 1).
since you have only one element in the array, this means that you need to access it with index = 0 , not index = 1
this is what the error trying to tell you.
回答3:
The Logcat indicates you are having error at line 74 in UsbDriver Class at:
if (!conn.claimInterface(Device_Details.getInterface(1), true)) { ...}
try replacing with 0 in the place of 1.
I don't know why you hardcoded this with 1.
来源：https://stackoverflow.com/questions/29344871/how-to-fix-java-lang-arrayindexoutofboundsexception-length-1-index-1