我正在开发一个Android应用程序，它将查询传输到蓝牙设备并从中检索数据。在应用程序中，通过点击屏幕上方的可用设备建立连接，然后在下半部分有一个按钮，触发发送查询，旁边的文本框显示数据。
我能够成功连接到设备并从中获取一次数据，但是当我第二次点击查询按钮时，应用程序崩溃了。
在代码中，我按下按钮后启动ConnectedThread线程，然后在线程代码的末尾调用一个处理程序，然后在屏幕上显示文本。我第二次按下按钮，我的代码再次尝试启动相同的线程 - 这会导致错误。 一旦接收到收到的数据，我一直试图阻止connectedThread ，这样我可以为每次发送 - 接收启动和关闭connectedThread。
您能否建议解决问题的方法或即兴创作代码结构的方法。任何帮助将不胜感激。 感谢
package com.test.bluetooth;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Set;
import java.util.UUID;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class Main_Activity extends Activity implements OnItemClickListener {
public static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
protected static final int SUCCESS_CONNECT = 0;
protected static final int MESSAGE_READ = 1;
BluetoothAdapter btAdapter;
Set<BluetoothDevice> devicesArray;
ArrayList<String> pairedDevices;
ArrayList<BluetoothDevice> devices;
ArrayAdapter<String> listAdapter;
ListView listView;
Button mConnect;
TextView mResponse;
IntentFilter filter;
BroadcastReceiver receiver;
String tag = "Debug";
Handler mHandler = new Handler(){
@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
Log.i(tag, "Handler starts");
super.handleMessage(msg);
switch(msg.what){
case SUCCESS_CONNECT:
final ConnectedThread connectedThread = new ConnectedThread((BluetoothSocket)msg.obj);
Toast.makeText(getApplicationContext(), "Connected", 0).show();
mConnect.setOnClickListener(
new View.OnClickListener()
{
public void onClick(View view)
{
//Log.v("EditText", mCommand.getText().toString());
//String Command = mCommand.getText().toString();
byte[] inputs = {0x30, 0x31, 0x30, 0x44, 0x0d, 0x0a};
connectedThread.write(inputs);
Log.i(tag, "sent ");
connectedThread.start();
Log.i(tag, "sent 2");
}
});
break;
case MESSAGE_READ:
byte[] TxBuf = (byte[])msg.obj;
String string = new String(TxBuf);
Log.d("ReceiverValue", string);
mResponse.setText(string);
break;
}
}
};
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
if(btAdapter.isDiscovering()){
btAdapter.cancelDiscovery();
}
if(listAdapter.getItem(arg2).contains("Paired")){
BluetoothDevice selectedDevice = devices.get(arg2);
ConnectThread connect = new ConnectThread(selectedDevice);
connect.start();
Log.i(tag, "in click listener");
}
else{
Toast.makeText(getApplicationContext(), "device is not paired", 0).show();
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
if(btAdapter==null){
Toast.makeText(getApplicationContext(), "No bluetooth detected", 0).show();
finish();
}
else{
if(!btAdapter.isEnabled()){
turnOn();
}
getPairedDevices();
startDiscovery();
}
}
private void startDiscovery() {
// TODO Auto-generated method stub
btAdapter.cancelDiscovery();
btAdapter.startDiscovery();
}
private void turnOn() {
// TODO Auto-generated method stub
Intent intent =new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(intent, 1);
}
private void getPairedDevices() {
// TODO Auto-generated method stub
devicesArray = btAdapter.getBondedDevices();
if(devicesArray.size()>0){
for(BluetoothDevice device:devicesArray){
pairedDevices.add(device.getName());
}
}
}
private void init() {
// TODO Auto-generated method stub
listView=(ListView)findViewById(R.id.listView);
mConnect=(Button)findViewById(R.id.bConnectNew);
//mCommand=(EditText)findViewById(R.id.etCommand);
mResponse=(TextView)findViewById(R.id.tvResponse);
listView.setOnItemClickListener(this);
listAdapter= new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,0);
listView.setAdapter(listAdapter);
btAdapter = BluetoothAdapter.getDefaultAdapter();
pairedDevices = new ArrayList<String>();
filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
devices = new ArrayList<BluetoothDevice>();
receiver = new BroadcastReceiver(){
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String action = intent.getAction();
if(BluetoothDevice.ACTION_FOUND.equals(action)){
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
devices.add(device);
String s = "";
for(int a = 0; a < pairedDevices.size(); a++){
if(device.getName().equals(pairedDevices.get(a))){
//append
s = "(Paired)";
break;
}
}
listAdapter.add(device.getName()+" "+s+" "+"\n"+device.getAddress());
}
else if(BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)){
}
else if(BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)){
}
else if(BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)){
if(btAdapter.getState() == btAdapter.STATE_OFF){
turnOn();
}
}
}
};
registerReceiver(receiver, filter);
filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
registerReceiver(receiver, filter);
filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
registerReceiver(receiver, filter);
filter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(receiver, filter);
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
unregisterReceiver(receiver);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
if(resultCode == RESULT_CANCELED){
Toast.makeText(getApplicationContext(), "Bluetooth must be enabled to continue", Toast.LENGTH_SHORT).show();
finish();
}
}
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to mmSocket,
// because mmSocket is final
BluetoothSocket tmp = null;
mmDevice = device;
Log.i(tag, "construct");
// Get a BluetoothSocket to connect with the given BluetoothDevice
try {
// MY_UUID is the app's UUID string, also used by the server code
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
Log.i(tag, "get socket failed");
}
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it will slow down the connection
btAdapter.cancelDiscovery();
Log.i(tag, "connect - run");
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mmSocket.connect();
Log.i(tag, "connect - succeeded");
} catch (IOException connectException) { Log.i(tag, "connect failed");
// Unable to connect; close the socket and get out
try {
mmSocket.close();
} catch (IOException closeException) { }
return;
}
// Do work to manage the connection (in a separate thread)
mHandler.obtainMessage(Main_Activity.SUCCESS_CONNECT, mmSocket).sendToTarget();
}
/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
try {
// Read from the InputStream
buffer = new byte[1024];
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI activity
mHandler.obtainMessage(Main_Activity.MESSAGE_READ, bytes, -1, buffer).sendToTarget();
} catch (IOException e) {
break;
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(byte[] bytes) {
try {
mmOutStream.write(bytes);
} catch (IOException e) { }
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
}
XML布局：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="Paired Devices"
android:id="@+id/tvPD"
/>
<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="100dip"
android:layout_above="@+id/Border"
android:layout_below="@+id/tvPD" >
</ListView>
<Button
android:id="@+id/bConnectNew"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/tvResponse"
android:layout_alignBottom="@+id/tvResponse"
android:layout_alignParentLeft="true"
android:layout_marginLeft="45dp"
android:text="Send" />
<TextView
android:id="@+id/tvResponse"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="188dp"
android:layout_marginRight="26dp"
android:text="Response displayed here" />
<View
android:id="@+id/Border"
android:layout_width="wrap_content"
android:layout_height="3dip"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:layout_weight="10"
android:background="@android:color/black" />
</RelativeLayout>
enter code here