问题
I'm creating Bluetooth chat app and I'm kinda new to Android programming. Atm my app can manage bluetooth connection and send/receive data. My problem is populating list view with strings because I'm not so good with creating Custom ArrayAdapters. I have 2 shapes (Red and Blue bubble) for sent and received messages (R.drawable.rounded_corner and R.drawable.rounded_corner_get). I'm managing bluetooth connection(ConnectedThread) in activity(MessengerActivity) as you can see in code bellow. So if anyone knows how can I create Custom ArrayAdapter for given code or knows any other similar StackOverflow question, I could really use help.
public class MessengerActivity extends AppCompatActivity {
protected static final int MESSAGE_READ = 5;
ConnectedThread mConnectedThhread;
static BluetoothSocket blueSocket;
String nameOfDevice;
public String message;
Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
Log.i("tag", "in handler");
switch (msg.what) {
case MESSAGE_READ:
byte[] readBuf = (byte[]) msg.obj;
String string = new String(readBuf);
try {
getMessage(string);
} catch (Exception e) {}
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_messenger);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
blueSocket = BluetoothSocketGet.blueSocket;
nameOfDevice = blueSocket.getRemoteDevice().getName();
toolbar.setTitle(nameOfDevice);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
mConnectedThhread = new ConnectedThread(blueSocket);
mConnectedThhread.start();
}
public void messageText(View v) {
EditText edit = (EditText) findViewById(R.id.textMessage);
String string;
string = edit.getText().toString();
edit.setText("");
mConnectedThhread.write(string.getBytes());
}
public void getMessage(String s) {
message=s;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_messenger, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
Intent intent = new Intent(android.provider.Settings.ACTION_SETTINGS);
startActivity(intent);
}
return super.onOptionsItemSelected(item);
}
protected 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(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() {
if (mmInStream != null) {
try {
mmInStream.close();
} catch (IOException e) {
}
}
if (mmOutStream != null) {
try {
mmOutStream.close();
} catch (IOException e) {
}
}
if (mmSocket != null) {
try {
mmSocket.close();
} catch (IOException e) {
}
}
}
}}
XML for MessengerActivity:
<LinearLayout 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"
android:orientation="vertical"
tools:context="com.example.milan.redtooth.MessengerActivityFragment"
tools:showIn="@layout/activity_messenger">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:transcriptMode="alwaysScroll"
android:stackFromBottom="true"
android:layout_weight="1"
android:divider="@null"
android:dividerHeight="0dp"
android:id="@+id/listMessages">
</ListView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_alignParentBottom="true">
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/textMessage"
android:layout_weight="1"
android:layout_gravity="bottom" />
<ImageButton
android:onClick="messageText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/sendMessage"
android:layout_gravity="bottom"
android:src="@drawable/ic_send_white_18dp" />
</LinearLayout>
回答1:
=> You have to define two list row layouts
1). item_send.xml for Sending message
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/msgr"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5sp"
android:layout_gravity="right"
android:layout_marginBottom="8dp"
android:layout_marginLeft="20dp"
android:background="@drawable/ic_send"
android:shadowColor="@color/textShadow"
android:shadowDx="1"
android:shadowDy="1"
android:text="Medium Texts"
android:textColor="@color/textColor"
android:textSize="18sp" />
</LinearLayout>
2). item_receive.xml for Receiving message
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/msgr"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="5sp"
android:layout_marginBottom="5dp"
android:layout_marginRight="20dp"
android:background="@drawable/ic_receive"
android:shadowColor="@color/textShadow"
android:shadowDx="1"
android:layout_gravity="left"
android:shadowDy="1"
android:text="Medium Text"
android:textColor="@color/textColor"
android:textSize="18sp" />
</LinearLayout>
[Replace the TextView Background with your own 9 patch bubble image for each row_layout (send and received)]
=> Now you have to create custom array adapter
class ChatArrayAdapter extends ArrayAdapter<ChatMessage> {
private TextView chatText;
private List<ChatMessage> chatMessageList = new ArrayList<ChatMessage>();
private Context context;
@Override
public void add(ChatMessage object) {
chatMessageList.add(object);
super.add(object);
}
public ChatArrayAdapter(Context context, int textViewResourceId) {
super(context, textViewResourceId);
this.context = context;
}
public int getCount() {
return this.chatMessageList.size();
}
public ChatMessage getItem(int index) {
return this.chatMessageList.get(index);
}
public View getView(int position, View convertView, ViewGroup parent) {
ChatMessage chatMessageObj = getItem(position);
View row = convertView;
LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (chatMessageObj.left) {
row = inflater.inflate(R.layout.item_send, parent, false);
} else {
row = inflater.inflate(R.layout.item_receive, parent, false);
}
chatText = (TextView) row.findViewById(R.id.msgr);
chatText.setText(chatMessageObj.message);
return row;
}
}
=> In Your Main Activity onCreate() method, just place following code
ChatArrayAdapter chatArrayAdapter = new ChatArrayAdapter(getApplicationContext(), R.layout.item_send);
ListView listView = (ListView) findViewById(R.id.listMessage);
listView.setAdapter(chatArrayAdapter);
listView.setTranscriptMode(AbsListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
listView.setAdapter(chatArrayAdapter);
//to scroll the list view to bottom on data change
chatArrayAdapter.registerDataSetObserver(new DataSetObserver() {
@Override
public void onChanged() {
super.onChanged();
listView.setSelection(chatArrayAdapter.getCount() - 1);
}
});
=> In Your Main Activity, just place following methods and call it on button click
private boolean receiveMessage(String msg) {
chatArrayAdapter.add(new ChatMessage(false, msg));
return true;
}
private boolean sendMessage(String msg) {
chatArrayAdapter.add(new ChatMessage(true, msg));
return true;
}
enter code here
来源：https://stackoverflow.com/questions/37081724/custom-array-adapter-for-chat-app