我使用android studio制作了一个应用程序，它使用蓝牙hc-06从arduino获取数据。在我的Android应用程序中，首先我在我的手机中搜索配对设备，然后使用蓝牙连接hc06，数据开始显示在#MainActivity上。
但是，当我去另一个活动时，我的蓝牙连接丢失，数据没有显示在SecondActivity上如何将蓝牙连接传递到另一个活动并显示来自arduino的数据，就像#MainActivity一样。
这是我的#MainActivity代码
package com.example.umair.bluetooth;
import android.support.v7.app.AppCompatActivity;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
int j1=0,j2=0,j3=0,j4=0,j5=0;
String smoke="",humi="",tempc="",tempf="",lat="",lng="";
TextView txtArduino, txtString, txtStringLength, sensorView0, sensorView1, sensorView2, sensorView3, sensorView4, sensorView5;
Handler bluetoothIn;
ImageButton btngps,pulseb;
final int handlerState = 0; //used to identify handler message
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private StringBuilder recDataString = new StringBuilder();
//Button btnn,btnn1;
private ConnectedThread mConnectedThread;
double lati=0;
double lngi=0;
// SPP UUID service - this should work for most devices
private static final UUID BTMODULEUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// String for MAC address
private static String address;
public static String address1 = "com.example.sheikh.bluetooth.address1";
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sensorView0 = (TextView) findViewById(R.id.sensorView0);
sensorView1 = (TextView) findViewById(R.id.sensorView1);
sensorView2 = (TextView) findViewById(R.id.sensorView2);
sensorView3 = (TextView) findViewById(R.id.sensorView3);
sensorView4 = (TextView) findViewById(R.id.sensorView4);
sensorView5 = (TextView) findViewById(R.id.sensorView5);
pulseb = (ImageButton)findViewById(R.id.pulsebutton);
btngps = (ImageButton)findViewById(R.id.btnShow);
bluetoothIn = new Handler() {
public void handleMessage(android.os.Message msg) {
if (msg.what == handlerState) { //if message is what we want
String readMessage = (String) msg.obj; // msg.arg1 = bytes from connect thread
recDataString.append(readMessage); //keep appending to string until ~
int endOfLineIndex = recDataString.indexOf("~"); // determine the end-of-line
if (endOfLineIndex > 0) { // make sure there data before ~
String dataInPrint = recDataString.substring(0, endOfLineIndex); // extract string
//txtString.setText("Data Received = " + dataInPrint);
int dataLength = dataInPrint.length(); //get length of data received
//txtStringLength.setText("String Length = " + String.valueOf(dataLength));
for(int i=0;i<endOfLineIndex;i++)
{
if(recDataString.charAt(i)=='A')
{
smoke = recDataString.substring(1, i);
j1=i+1;
}
else if(recDataString.charAt(i)=='B')
{
humi = recDataString.substring(j1, i);
j2=i+1;
}
else if(recDataString.charAt(i)=='C')
{
tempc = recDataString.substring(j2, i);
j3=i+1;
}
else if(recDataString.charAt(i)=='D')
{
tempf = recDataString.substring(j3, i);
j4=i+1;
}
else if(recDataString.charAt(i)=='E')
{
lat = recDataString.substring(j4, i);
j5=i+1;
}
else if(recDataString.charAt(i)=='F')
{
lng = recDataString.substring(j5, i);
}
}
if (recDataString.charAt(0) == '#') //if it starts with # we know it is what we are looking for
{
sensorView0.setText(smoke);
sensorView1.setText(humi);
sensorView2.setText(tempc);
sensorView3.setText(tempf);
sensorView4.setText(lat);
sensorView5.setText(lng);
lati = Double.parseDouble(lat);
lngi = Double.parseDouble(lng);
}
recDataString.delete(0, recDataString.length()); //clear all string data
}
}
}
};
btAdapter = BluetoothAdapter.getDefaultAdapter(); // get Bluetooth adapter
checkBTState();
btngps.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(getBaseContext(), MapsActivity1.class);
// Passing latitude and longitude to the MapActiv
intent.putExtra("lat", lati);
intent.putExtra("lng", lngi);
startActivity(intent);
}
});
pulseb.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(MainActivity.this, showpulse.class);
i.putExtra(address1, address);
startActivity(i);
}
});
}
private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {
return device.createRfcommSocketToServiceRecord(BTMODULEUUID);
//creates secure outgoing connecetion with BT device using UUID
}
@Override
public void onResume() {
super.onResume();
//Get MAC address from DeviceListActivity via intent
Intent intent = getIntent();
//Get the MAC address from the DeviceListActivty via EXTRA
address = intent.getStringExtra(DeviceListActivity.EXTRA_DEVICE_ADDRESS);
//create device and set the MAC address
BluetoothDevice device = btAdapter.getRemoteDevice(address);
try {
btSocket = createBluetoothSocket(device);
} catch (IOException e) {
Toast.makeText(getBaseContext(), "Socket creation failed", Toast.LENGTH_LONG).show();
}
// Establish the Bluetooth socket connection.
try
{
btSocket.connect();
} catch (IOException e) {
try
{
btSocket.close();
} catch (IOException e2)
{
//insert code to deal with this
}
}
mConnectedThread = new ConnectedThread(btSocket);
mConnectedThread.start();
//I send a character when resuming.beginning transmission to check device is connected
//If it is not an exception will be thrown in the write method and finish() will be called
mConnectedThread.write("0");
}
@Override
public void onPause()
{
super.onPause();
try
{
//Don't leave Bluetooth sockets open when leaving activity
btSocket.close();
} catch (IOException e2) {
//insert code to deal with this
}
}
//Checks that the Android device Bluetooth is available and prompts to be turned on if off
private void checkBTState() {
if(btAdapter==null) {
Toast.makeText(getBaseContext(), "Device does not support bluetooth", Toast.LENGTH_LONG).show();
} else {
if (btAdapter.isEnabled()) {
} else {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
}
}
}
//create new class for connect thread
private class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
//creation of the connect thread
public ConnectedThread(BluetoothSocket socket) {
InputStream tmpIn = null;
OutputStream tmpOut = null;
try {
//Create I/O streams for connection
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) { }
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
byte[] buffer = new byte[256];
int bytes;
// Keep looping to listen for received messages
while (true) {
try {
bytes = mmInStream.read(buffer); //read bytes from input buffer
String readMessage = new String(buffer, 0, bytes);
// Send the obtained bytes to the UI Activity via handler
bluetoothIn.obtainMessage(handlerState, bytes, -1, readMessage).sendToTarget();
} catch (IOException e) {
break;
}
}
}
//write method
public void write(String input) {
byte[] msgBuffer = input.getBytes(); //converts entered String into bytes
try {
mmOutStream.write(msgBuffer); //write bytes over BT connection via outstream
} catch (IOException e) {
//if you cannot write, close the application
Toast.makeText(getBaseContext(), "Connection Failure", Toast.LENGTH_LONG).show();
finish();
}
}
}
}
这是我的DeviceListActivity代码
package com.example.umair.bluetooth;
import java.util.Set;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.os.Bundle;
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.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class DeviceListActivity extends Activity {
// Debugging for LOGCAT
private static final String TAG = "DeviceListActivity";
private static final boolean D = true;
// declare button for launching website and textview for connection status
Button tlbutton;
TextView textView1;
// EXTRA string to send on to mainactivity
public static String EXTRA_DEVICE_ADDRESS = "device_address";
// Member fields
private BluetoothAdapter mBtAdapter;
private ArrayAdapter<String> mPairedDevicesArrayAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_device_list);
}
@Override
public void onResume()
{
super.onResume();
//***************
checkBTState();
textView1 = (TextView) findViewById(R.id.connecting);
textView1.setTextSize(40);
textView1.setText(" ");
// Initialize array adapter for paired devices
mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
// Find and set up the ListView for paired devices
ListView pairedListView = (ListView) findViewById(R.id.paired_devices);
pairedListView.setAdapter(mPairedDevicesArrayAdapter);
pairedListView.setOnItemClickListener(mDeviceClickListener);
// Get the local Bluetooth adapter
mBtAdapter = BluetoothAdapter.getDefaultAdapter();
// Get a set of currently paired devices and append to 'pairedDevices'
Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices();
// Add previosuly paired devices to the array
if (pairedDevices.size() > 0) {
// findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);//make title viewable
for (BluetoothDevice device : pairedDevices) {
mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
}
} else {
String noDevices = getResources().getText(R.string.none_paired).toString();
mPairedDevicesArrayAdapter.add(noDevices);
}
}
// Set up on-click listener for the list (nicked this - unsure)
private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) {
textView1.setText("Connecting...");
// Get the device MAC address, which is the last 17 chars in the View
String info = ((TextView) v).getText().toString();
String address = info.substring(info.length() - 17);
// Make an intent to start next activity while taking an extra which is the MAC address.
Intent i = new Intent(DeviceListActivity.this, MainActivity.class);
i.putExtra(EXTRA_DEVICE_ADDRESS, address);
startActivity(i);
}
};
//method to check if the device has Bluetooth and if it is on.
//Prompts the user to turn it on if it is off
private void checkBTState() {
// Check device has Bluetooth and that it is turned on
mBtAdapter=BluetoothAdapter.getDefaultAdapter(); // CHECK THIS OUT THAT IT WORKS!!!
if(mBtAdapter==null) {
Toast.makeText(getBaseContext(), "Device does not support Bluetooth", Toast.LENGTH_SHORT).show();
} else {
if (mBtAdapter.isEnabled()) {
Log.d(TAG, "...Bluetooth ON...");
} else {
//Prompt user to turn on Bluetooth
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
}
}
}
}
如何通过蓝牙连接并在第3次活动中显示arduino数据