Android中的蓝牙连接>4.1.2 [英] Bluetooth connection in Android > 4.1.2
本文介绍了Android中的蓝牙连接>4.1.2的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我编写了以下活动来将我的 Nexus 7 与 Arduino 连接起来，只需交换 0 和 1 即可打开和关闭 LED.我从这里举了一个例子:http://developer.android.com/guide/topics/connectivity/bluetooth.html#ManagingAConnection并且还在这里回忆:如何在 Android 中以编程方式连接配对的蓝牙设备?
I wrote the following activity to connect my Nexus 7 with Arduino, to simply exchange 0 and 1 to switch on and off a led. I took example from here: http://developer.android.com/guide/topics/connectivity/bluetooth.html#ManagingAConnection and also recalled here: How to connect with paired Bluetooth device programmatic in Android?
但它几乎从不连接，或者如果连接不显示 UI.应用在暂停或恢复时几乎总是崩溃.
but it almost never connects or if it connects does not display UI. Almost all the time the app crashes when paused or resumed.
我确定线程的编写方式有问题，但无法理解在哪里.
I'm sure there is something wrong in how threads are written, but cannot understand where.
package com.example.bluetooth3;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final String TAG = "bluetooth2";
Button btnOn, btnOff;
TextView txtArduino;
Handler h;
final int receivedMessage = 1; // Status for Handler
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private StringBuilder sb = new StringBuilder();
private ConnectedThread mConnectedThread;
private ConnectThread mConnectThread;
// SPP UUID service
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// MAC-address of Bluetooth module (you must edit this line)
private static String address = "00:06:66:60:1D:09";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnOn = (Button) findViewById(R.id.btnOn); // button LED ON
btnOff = (Button) findViewById(R.id.btnOff); // button LED OFF
txtArduino = (TextView) findViewById(R.id.txtArduino); // for display the received data from the Arduino
h = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case receivedMessage: // if receive massage
byte[] readBuf = (byte[]) msg.obj;
String strIncom = new String(readBuf, 0, msg.arg1); // create string from bytes array
sb.append(strIncom); // append string
int endOfLineIndex = sb.indexOf("\r\n"); // determine the end-of-line
if (endOfLineIndex > 0) { // if end-of-line,
String sbprint = sb.substring(0, endOfLineIndex); // extract string
sb.delete(0, sb.length()); // and clear
txtArduino.setText("Data from Arduino: " + sbprint); // update TextView
btnOff.setEnabled(true);
btnOn.setEnabled(true);
}
//Log.d(TAG, "...String:"+ sb.toString() + "Byte:" + msg.arg1 + "...");
break;
}
};
};
btAdapter = BluetoothAdapter.getDefaultAdapter(); // get Bluetooth adapter
btnOn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
btnOn.setEnabled(false);
mConnectedThread.write("1"); // Send "1" via Bluetooth
//Toast.makeText(getBaseContext(), "Turn on LED", Toast.LENGTH_SHORT).show();
}
});
btnOff.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
btnOff.setEnabled(false);
mConnectedThread.write("0"); // Send "0" via Bluetooth
//Toast.makeText(getBaseContext(), "Turn off LED", Toast.LENGTH_SHORT).show();
}
});
}
@Override
public void onResume() {
super.onResume();
Log.d(TAG, "...onResume - try connect...");
checkBTState();
// Set up a pointer to the remote node using it's address.
BluetoothDevice device = btAdapter.getRemoteDevice(address);
mConnectThread=new ConnectThread(device);
mConnectThread.run();
}
@Override
public void onPause() {
super.onPause();
Log.d(TAG, "...In onPause()...");
//try {
// btSocket.close();
//} catch (IOException e2) {
// errorExit("Fatal Error", "In onPause() and failed to close socket." + e2.getMessage() + ".");
//}
mConnectedThread.cancel();
}
private void checkBTState() {
// Check for Bluetooth support and then check to make sure it is turned on
// Emulator doesn't support Bluetooth and will return null
if(btAdapter==null) {
errorExit("Fatal Error", "Bluetooth not support");
} else {
if (btAdapter.isEnabled()) {
Log.d(TAG, "...Bluetooth ON...");
} else {
//Prompt user to turn on Bluetooth
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
}
}
}
private void errorExit(String title, String message){
Toast.makeText(getBaseContext(), title + " - " + message, Toast.LENGTH_LONG).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;
// 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) { }
mmSocket = tmp;
}
public void run() {
//android.os.Debug.waitForDebugger();
// Cancel discovery because it will slow down the connection
Log.d(TAG, "prova");
btAdapter.cancelDiscovery();
try {
// Connect the device through the socket. This will block
// until it succeeds or throws an exception
mmSocket.connect();
} catch (IOException connectException) {
// 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)
mConnectedThread=new ConnectedThread(mmSocket);
mConnectedThread.run();
}
/** 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() {
//android.os.Debug.waitForDebugger();
byte[] buffer = new byte[1024]; // 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
bytes = mmInStream.read(buffer);
// Send the obtained bytes to the UI Activity
h.obtainMessage(receivedMessage, bytes, -1, buffer)
.sendToTarget();
} catch (IOException e) {
break;
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(String message) {
Log.d(TAG, "...Data to send: " + message + "...");
byte[] msgBuffer = message.getBytes();
try {
mmOutStream.write(msgBuffer);
} catch (IOException e) {
Log.d(TAG, "...Error data send: " + e.getMessage() + "...");
}
}
/* Call this from the main Activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
}
我还尝试了在此处找到的其他活动，该活动效果更好，但不使用分离的线程进行连接.但是仍然有问题，因为它在恢复后有时会崩溃，特别是如果没有连接蓝牙，或者它可以正常恢复但没有连接到 Arduino BT 设备.
I also tried an other activity found here which works better but does not use separated thread to connect. But still has problems as far as it sometime crashes after resuming, specially if bluetooth is not connected, or it resumes properly but does not connect to the Arduino BT device.
package com.example.bluetooth2;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.util.UUID;
import com.example.bluetooth2.R;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final String TAG = "bluetooth2";
Button btnOn, btnOff;
TextView txtArduino;
Handler h;
final int RECIEVE_MESSAGE = 1; // Status for Handler
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private StringBuilder sb = new StringBuilder();
private ConnectedThread mConnectedThread;
// SPP UUID service
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// MAC-address of Bluetooth module (you must edit this line)
private static String address = "00:06:66:60:1D:09";
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnOn = (Button) findViewById(R.id.btnOn); // button LED ON
btnOff = (Button) findViewById(R.id.btnOff); // button LED OFF
txtArduino = (TextView) findViewById(R.id.txtArduino); // for display the received data from the Arduino
h = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case RECIEVE_MESSAGE: // if receive massage
byte[] readBuf = (byte[]) msg.obj;
String strIncom = new String(readBuf, 0, msg.arg1); // create string from bytes array
sb.append(strIncom); // append string
int endOfLineIndex = sb.indexOf("\r\n"); // determine the end-of-line
if (endOfLineIndex > 0) { // if end-of-line,
String sbprint = sb.substring(0, endOfLineIndex); // extract string
sb.delete(0, sb.length()); // and clear
txtArduino.setText("Data from Arduino: " + sbprint); // update TextView
btnOff.setEnabled(true);
btnOn.setEnabled(true);
}
//Log.d(TAG, "...String:"+ sb.toString() + "Byte:" + msg.arg1 + "...");
break;
}
};
};
btAdapter = BluetoothAdapter.getDefaultAdapter(); // get Bluetooth adapter
checkBTState();
btnOn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
btnOn.setEnabled(false);
mConnectedThread.write("1"); // Send "1" via Bluetooth
//Toast.makeText(getBaseContext(), "Turn on LED", Toast.LENGTH_SHORT).show();
}
});
btnOff.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
btnOff.setEnabled(false);
mConnectedThread.write("0"); // Send "0" via Bluetooth
//Toast.makeText(getBaseContext(), "Turn off LED", Toast.LENGTH_SHORT).show();
}
});
}
private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {
if(Build.VERSION.SDK_INT >= 10){
try {
final Method m = device.getClass().getMethod("createInsecureRfcommSocketToServiceRecord", new Class[] { UUID.class });
return (BluetoothSocket) m.invoke(device, MY_UUID);
} catch (Exception e) {
Log.e(TAG, "Could not create Insecure RFComm Connection",e);
}
}
return device.createRfcommSocketToServiceRecord(MY_UUID);
}
@Override
public void onResume() {
super.onResume();
Log.d(TAG, "...onResume - try connect...");
// Set up a pointer to the remote node using it's address.
BluetoothDevice device = btAdapter.getRemoteDevice(address);
// Two things are needed to make a connection:
// A MAC address, which we got above.
// A Service ID or UUID. In this case we are using the
// UUID for SPP.
try {
btSocket = createBluetoothSocket(device);
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
}
/*try {
btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
}*/
// Discovery is resource intensive. Make sure it isn't going on
// when you attempt to connect and pass your message.
btAdapter.cancelDiscovery();
// Establish the connection. This will block until it connects.
Log.d(TAG, "...Connecting...");
try {
btSocket.connect();
Log.d(TAG, "....Connection ok...");
} catch (IOException e) {
try {
btSocket.close();
Log.d(TAG, "Failing connect 1 "+e.getMessage());
} catch (IOException e2) {
Log.d(TAG, "Failing connect 2");
errorExit("Fatal Error", "In onResume() and unable to close socket during connection failure" + e2.getMessage() + ".");
}
}
// Create a data stream so we can talk to server.
Log.d(TAG, "...Create Socket...");
mConnectedThread = new ConnectedThread(btSocket);
mConnectedThread.start();
}
@Override
public void onPause() {
super.onPause();
Log.d(TAG, "...In onPause()...");
//try {
//btSocket.close();
mConnectedThread.cancel();
//} catch (IOException e2) {
// errorExit("Fatal Error", "In onPause() and failed to close socket." + e2.getMessage() + ".");
//}
}
private void checkBTState() {
// Check for Bluetooth support and then check to make sure it is turned on
// Emulator doesn't support Bluetooth and will return null
if(btAdapter==null) {
errorExit("Fatal Error", "Bluetooth not support");
} else {
if (btAdapter.isEnabled()) {
Log.d(TAG, "...Bluetooth ON...");
} else {
//Prompt user to turn on Bluetooth
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
}
}
}
private void errorExit(String title, String message){
Toast.makeText(getBaseContext(), title + " - " + message, Toast.LENGTH_LONG).show();
finish();
}
private class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
private final BluetoothSocket mmSocket;
public ConnectedThread(BluetoothSocket socket) {
InputStream tmpIn = null;
OutputStream tmpOut = null;
BluetoothSocket tmpSck=null;
// Get the input and output streams, using temp objects because
// member streams are final
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
tmpSck=socket;
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
mmSocket=tmpSck;
}
public void run() {
android.os.Debug.waitForDebugger();
byte[] buffer = new byte[256]; // 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
bytes = mmInStream.read(buffer); // Get number of bytes and message in "buffer"
h.obtainMessage(RECIEVE_MESSAGE, bytes, -1, buffer).sendToTarget(); // Send to message queue Handler
} catch (IOException e) {
break;
} catch (NullPointerException npe) {
Log.d(TAG,npe.getMessage());
}
}
}
/* Call this from the main activity to send data to the remote device */
public void write(String message) {
Log.d(TAG, "...Data to send: " + message + "...");
byte[] msgBuffer = message.getBytes();
try {
mmOutStream.write(msgBuffer);
} catch (IOException e) {
Log.d(TAG, "...Error data send: " + e.getMessage() + "...");
}
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
我在某处读到过，在 ICS 之后，Android 有一些与操作系统本身相关的蓝牙问题......我真的希望情况不是这样......非常感谢您的帮助.
I've read somewhere that Android after ICS has some issue with bluetooth tied to the OS itself.... I really hope this is not the case... Your help is greatly appreciated.
推荐答案
Android 4.2 具有完全重新设计的蓝牙堆栈 (Bluedroid)，而早期版本使用的是 Bluez.在 4.2 中，Bluedroid 已知在连接到 RFCOMM(也称为 SPP)时存在问题.请参阅此处:https://code.google.com/p/android/问题/详细信息?id=41110
Android 4.2 has a completely redesigned Bluetooth stack (Bluedroid), while earlier versions used Bluez. In 4.2 Bluedroid is known to have issues connecting to RFCOMM (also known as SPP). See here: https://code.google.com/p/android/issues/detail?id=41110
Android 4.3 据说修复了它.您可以尝试使用来自 https://developers.google.com/android/的固件映像升级到 4.3联系/图像，看看是否能解决问题.
Android 4.3 supposedly fixes it. You can try upgrading to 4.3 with a firmware image from https://developers.google.com/android/nexus/images and see if that fixes the issue.
这篇关于Android中的蓝牙连接>4.1.2的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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