首先，我很抱歉我的英语不好，我希望你能理解我。
APP：
1个包含3个片段和PageAdaptater的活动确定
从蓝牙设备收集数据。的确定
每次通过处理程序在MainActivity中收集数据时，都会更新片段中的TextView。
在我的代码下面：
MainActivity：
public class MainActivity extends FragmentActivity {
private PagerAdapter mPagerAdapter;
private static final String TAG = "bluetooth2";
private String btaddr = "20:14:09:17:00:40";
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;
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.viewpager);
// Création de la liste de Fragments que fera défiler le PagerAdapter
List<Fragment> fragments = new Vector<Fragment>();
// Ajout des Fragments dans la liste
fragments.add(Fragment.instantiate(this,HomeFragment.class.getName()));
fragments.add(Fragment.instantiate(this,NormalFragment.class.getName()));
fragments.add(Fragment.instantiate(this,ConfigFragment.class.getName()));
// Création de l'adapter qui s'occupera de l'affichage de la liste de
// Fragments
this.mPagerAdapter = new MyPagerAdapter(super.getSupportFragmentManager(), fragments);
ViewPager pager = (ViewPager) super.findViewById(R.id.viewpager);
// Affectation de l'adapter au ViewPager
pager.setAdapter(this.mPagerAdapter);
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
Log.d(TAG, "...String:"+ sb.toString() + "Byte:" + msg.arg1 + "...");
//My question : How to send data to fragment from here ?
break;
}
}
};
};
btAdapter = BluetoothAdapter.getDefaultAdapter(); // get Bluetooth adapter
checkBTState();
}
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(btaddr);
// 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() + ".");
}
// 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();
} catch (IOException e2) {
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();
} 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();
}
public class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket 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 = 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;
}
}
}
/* 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() + "...");
}
}
}
}
HomeFragment（接收者）：
public class HomeFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View myInflatedView = inflater.inflate(R.layout.home_layout, container, false);
return myInflatedView;
}
}
家庭布局：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/data"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="20dp"
android:text="DATA" />
</LinearLayout>
在这种情况下，对于您来说，如何从活动中的处理程序轻松地将数据发送到HomeFragment并更新内部的textview？
我是Java的新手，大多数教程都是英文的，关于文档也是如此，所以单独学习很难...
我尝试了很多在stackoverflow上找到的片段而没有成功，现在我有点迷失了..
编辑1：
根据要求，这里是PagerAdaptater的代码：
public class MyPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> fragments;
//On fournit à l'adapter la liste des fragments à afficher
public MyPagerAdapter(FragmentManager fm, List<Fragment> fragments) {
super(fm);
this.fragments = fragments;
}
@Override
public Fragment getItem(int position) {
return this.fragments.get(position);
}
@Override
public int getCount() {
return this.fragments.size();
}
}
编辑2：
更新了HomeFragment：
public class HomeFragment extends Fragment {
TextView data;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View myInflatedView = inflater.inflate(R.layout.home_layout, container, false);
data= (TextView) myInflatedView.findViewById(R.id.data);
return myInflatedView;
}
public void change(String txt){
data.setText(txt); //Don't WORK "NullPointerException"
Log.d("TEST", "...String:"+ txt + "..."); //Work
}
}
编辑3：
解决方案，在执行setText之前检查数据是否为空。
public void change(String txt){
if(data != null){
data.setText(str);
}
Log.d("TEST", "...String:"+ txt + "..."); //Work
}
答案 0 :(得分：0)
您可以在MainActivity中保留对HomeFragment的引用，并将其添加到寻呼机适配器：
public class MainActivity extends FragmentActivity {
// instanciate other variables
private HomeFragment myHomeFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.
List<Fragment> fragments = new Vector<Fragment>();
this.myHomeFragment = fragment.instantiate(this,HomeFragment.class.getName());
fragments.add(myHomeFragment);
fragments.add(Fragment.instantiate(this,NormalFragment.class.getName()));
fragments.add(Fragment.instantiate(this,ConfigFragment.class.getName()));
...
}
}
然后，在HomeFragment中，声明一个公共方法，它接受一个字符串并设置TextView的文本并在你的处理程序中调用它：
myHomeFragment.setTextView(sb.toString());