我正在制作蓝牙应用，尝试在活动之间传递BluetoothConnection类的实例（其中包含内部类ConnectThread和ConnectedThread）。 BlindsActivity上的etIntgent（）返回＆＃34; BlindsActivity＆＃34;，而不是实际的父意图。 getParentActivityIntent（）似乎有效，但是调用getParentActivityIntent（）。getExtra总是返回null，即使对于String数据也是如此。
DeviceListActivity的代码:(父活动）
公共类DeviceListActivity扩展AppCompatActivity实现Serializable {
//widgets ListView devicesView; //Bluetooth private BluetoothAdapter btAdapter; private BluetoothDevice btDevice; private Set<BluetoothDevice> setPairedDevices; private ArrayList arrayListPairedDevices; private BluetoothConnection btConnection; public boolean connected; @Override protected void onCreate(Bundle savedInstanceState) { //set view super.onCreate(savedInstanceState); setContentView(R.layout.activity_bluetooth); //call widgets devicesView = (ListView) findViewById(R.id.listViewDeviceList); //TEST String s = getIntent().getStringExtra("TEST"); //check bluetooth is avaiable and on btAdapter = BluetoothAdapter.getDefaultAdapter(); if (btAdapter == null) { displayMessage("Device doesn't support bluetooth"); finish(); } else if (!btAdapter.isEnabled()) {//if bluetooth is switched off request permission to turn on Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBtIntent, 1); } //get all paired devices arrayListPairedDevices = new ArrayList(); setPairedDevices = btAdapter.getBondedDevices();//Set of all paired devices if (setPairedDevices.size() > 0) { //if there are paired devices, get name and MAC address of each for (BluetoothDevice dev : setPairedDevices){ arrayListPairedDevices.add(dev.getName() + "\n" + dev.getAddress()); } } else if(!btAdapter.isEnabled()) { displayMessage("Please enable Bluetooth before proceeding"); finish(); } else{ displayMessage("No paired devices\nPair with relevant device before proceeding"); finish(); } //display bluetooth devices final ArrayAdapter arrAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, arrayListPairedDevices); devicesView.setAdapter(arrAdapter); devicesView.setOnItemClickListener(myListClickListener); //Method called when the device from the list is clicked } private AdapterView.OnItemClickListener myListClickListener = new AdapterView.OnItemClickListener() {//make listView items clickable public void onItemClick(AdapterView av, View v, int arg2, long arg3) { //get the device MAC address, the last 17 chars in the View String info = ((TextView) v).getText().toString(); String address = info.substring(info.length() - 17); btDevice = btAdapter.getRemoteDevice(address);//create new device with chosen address //CONNECTION HAPPENS HERE btConnection = new BluetoothConnection(btDevice); if(btConnection.connect()){ //if connection success Intent intent = new Intent(DeviceListActivity.this, BlindsActivity.class); intent.putExtra("TEST", "test"); intent.putExtra("CONNECTION", (Serializable) btConnection); startActivity(intent); } else{ displayMessage("Error connecting - please try again"); } } }; private void displayMessage(String s) { Toast.makeText(getApplicationContext(), s, Toast.LENGTH_LONG).show(); }
BlindsActivity的相关代码片段:(子/接收活动） 注意getParentActivityIntent（）在这里返回正确的意图，但getIntent（）不是。
BluetoothConnection btConnection和String都为空
public class BlindsActivity extends AppCompatActivity implements Serializable {
//widgets
private Button btnProgram, btnOpen, btnClose, btn34Open, btn34Close, btnCustom, btnSetup, btnSubmit, btnDisconnect;
private TextView txtViewConnected;
@Override
protected void onNewIntent(Intent intent){
super.onNewIntent(intent);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
//set view
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_blinds);
//call widgets
btnProgram = (Button) findViewById(R.id.btnProgram);
btnOpen = (Button) findViewById(R.id.btnOpen);
btnClose = (Button) findViewById(R.id.btnClose);
btn34Open = (Button) findViewById(R.id.btn34Open);
btn34Close = (Button) findViewById(R.id.btn34Closed);
btnCustom = (Button) findViewById(R.id.btnCustom);
btnSetup = (Button) findViewById(R.id.btnSetUp);
btnSubmit = (Button) findViewById(R.id.btnSubmit);
btnDisconnect = (Button) findViewById(R.id.btnDisconnect);
//set action bar title
ActionBar actionBar = getSupportActionBar();
actionBar.setTitle("Blinds");
//receive instance of BluetoothConnection from previous activity
Intent i = getParentActivityIntent();
String s = i.getStringExtra("TEST");
BluetoothConnection btConnection = (BluetoothConnection) i.getSerializableExtra("CONNECTION");
//get instance of ConnectedThread from BluetoothActivity
final BluetoothConnection.ConnectedThread connectedThread = btConnection.connectedThread;
BluetoothConnection类：
public class BluetoothConnection implements Serializable {
//Bluetooth
private BluetoothDevice btDevice;
public ConnectThread connectThread;
public ConnectedThread connectedThread;
private boolean connected;
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
public BluetoothConnection (BluetoothDevice device){
//constructor
btDevice = device;
}
public boolean connect(){
//initialises ConnectThread - done here for syncing with UI Thread and passing between activities
connectThread = new ConnectThread(btDevice);
connectThread.start();
try{
// sync threads to return only after the connection is created
connectThread.join();
} catch (InterruptedException e) {e.printStackTrace();}
return connected;
}
@SuppressLint("HandlerLeak")
Handler handler = new Handler(){
@Override
public void handleMessage(Message msg){
byte[] writeBuf = (byte[]) msg.obj;
int begin = (int)msg.arg1;
int end = (int)msg.arg2;
switch(msg.what){
case 1:
String writeMessage = new String(writeBuf);
writeMessage = writeMessage.substring(begin, end);
break;
}
}
};
public class ConnectThread extends Thread implements Serializable{
public final BluetoothSocket btSocket;
public ConnectThread(BluetoothDevice btDevice){
//constructor
BluetoothSocket tmpSocket = null;
try {//attempts to obtain and open a Bluetooth Socket, uses temp socket until confirmed working
tmpSocket = btDevice.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {e.printStackTrace();}
btSocket = tmpSocket;
}
public void run(){
//attempts to connect socket to remote device
try{
btSocket.connect();
connected = true;
} catch (IOException e) {e.printStackTrace(); connected = false; return;}
connectedThread = new ConnectedThread(btSocket);
connectedThread.start();
}
public boolean disconnect(){
try {
btSocket.close();
} catch (IOException e) {e.printStackTrace(); return false;}
return true;
}
}//end class ConnectThread
public class ConnectedThread extends Thread implements Serializable{
private final InputStream inStream;
private final OutputStream outStream;
private final BluetoothSocket btSocket;
public ConnectedThread(BluetoothSocket socket){
//constructor
btSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
try{ //attempts to open input and output streams on socket
tmpIn = btSocket.getInputStream();
tmpOut = btSocket.getOutputStream();
} catch (IOException e) {e.printStackTrace();}
inStream = tmpIn;
outStream = tmpOut;
}
public void run(){
byte[] buffer = new byte[1024];
int begin = 0;
int bytes = 0;
while (true){
try{
bytes += inStream.read(buffer, bytes, buffer.length - bytes);
for (int i = begin; i < bytes; i++){
if (buffer[i] == "#".getBytes()[0]){
handler.obtainMessage(1, begin, i, buffer).sendToTarget();
begin = i+1;
if(i == (bytes - 1)){
bytes = begin = 0;
}
}
}
} catch (IOException e) {e.printStackTrace(); break;}
}
}
public void write(byte[] bytes){
try{
outStream.write(bytes);
} catch (IOException e) {e.printStackTrace();}
}
public void cancel(){
try{
btSocket.close();
} catch(IOException e) {e.printStackTrace();}
}
}
}//END
这是我的AndroidManifest.xml
<uses-permission android:name="android.permission.BLUETOOTH" /> <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" /> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity" android:configChanges="orientation" android:label="@string/app_name" android:screenOrientation="portrait" android:theme="@style/AppTheme.NoActionBar"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".DeviceListActivity" android:configChanges="orientation" android:parentActivityName=".MainActivity" android:screenOrientation="portrait" /> <activity android:name=".BlindsActivity" android:configChanges="orientation" android:parentActivityName=".DeviceListActivity" android:screenOrientation="portrait" /> <activity android:name=".ProgramActivity" android:configChanges="orientation" android:parentActivityName=".BlindsActivity" android:screenOrientation="portrait" /> <activity android:name=".SetUpActivity" /> </application>