[Android Q&A, Help & Troubleshooting] kuronatsu:
Hello,

Recently I started working on bluetooth chat app for my final year project. I took the example coding available in the sample app in Eclipse and trying to improve it. Now I'm trying to insert 2 new functions into it, 1 - the upload button for uploading any files, 2 - bubble chat interface.

I am a beginner at android programming. I tried exploring draw 9 patch for the bubble patch. Somehow I get the bubble chat done, but not perfectly. I can make it send & receive with the same bubble style. What I'm trying to do is, receive message will show in Green bubble while send message will show Yellow Bubble. I tried the getView() method but didn't understand any of it.

As for the upload button, I'm having problem at the uploading part. I get the selecting the file part done, but I don't know how to make it automatically send the file after it being selected. I tried Googling and most of the result show Image upload. Thanks for those image upload tutorial, I get as far as choosing the file. As for uploading it(sending the file to the other paired device), I'm completely clueless...

The part that I'm having problem I highlight it with red color.

Here's my coding(technically it isn't my coding, it the sample coding with minor modification):

package com.example.android.BluetoothChat;

import android.annotation.TargetApi;

import android.app.Activity;

import android.bluetooth.BluetoothAdapter;

import android.bluetooth.BluetoothDevice;

import android.content.Intent;

import android.os.Build;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.util.Log;

import android.view.KeyEvent;

import android.view.Menu;

import android.view.MenuInflater;

import android.view.MenuItem;

import android.view.View;

import android.view.Window;

import android.view.View.OnClickListener;

import android.view.inputmethod.EditorInfo;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.EditText;

import android.widget.ListView;

import android.widget.SimpleAdapter.ViewBinder;

import android.widget.TextView;

import android.widget.Toast;

/**

* This is the main Activity that displays the current chat session.

*/

@TargetApi(Build.VERSION_CODES.ECLAIR)

public class BluetoothChat extends Activity {

// Debugging

private static final String TAG = "BluetoothChat";

private static final boolean D = true;

// Message types sent from the BluetoothChatService Handler

public static final int MESSAGE_STATE_CHANGE = 1;

public static final int MESSAGE_READ = 2;

public static final int MESSAGE_WRITE = 3;

public static final int MESSAGE_DEVICE_NAME = 4;

public static final int MESSAGE_TOAST = 5;

// Key names received from the BluetoothChatService Handler

public static final String DEVICE_NAME = "device_name";

public static final String TOAST = "toast";

// Intent request codes

private static final int REQUEST_CONNECT_DEVICE_SECURE = 1;

private static final int REQUEST_CONNECT_DEVICE_INSECURE = 2;

private static final int REQUEST_ENABLE_BT = 3;

// Layout Views

private TextView mTitle;

private ListView mConversationView;

private EditText mOutEditText;

private Button mSendButton;

private Button mUploadButton;

// Name of the connected device

private String mConnectedDeviceName = null;

// Array adapter for the conversation thread

private ArrayAdapter<String> mConversationArrayAdapter;

// String buffer for outgoing messages

private StringBuffer mOutStringBuffer;

// Local Bluetooth adapter

private BluetoothAdapter mBluetoothAdapter = null;

// Member object for the chat services

private BluetoothChatService mChatService = null;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

if(D) Log.e(TAG, "+++ ON CREATE +++");

// Set up the window layout

requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);

setContentView(R.layout.main);

getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.custom_title);

// Set up the custom title

mTitle = (TextView) findViewById(R.id.title_left_text);

mTitle.setText(R.string.app_name);

mTitle = (TextView) findViewById(R.id.title_right_text);

// Get local Bluetooth adapter

mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

// If the adapter is null, then Bluetooth is not supported

if (mBluetoothAdapter == null) {

Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show();

finish();

return;

}

}

@Override

public void onStart() {

super.onStart();

if(D) Log.e(TAG, "++ ON START ++");

// If BT is not on, request that it be enabled.

// setupChat() will then be called during onActivityResult

if (!mBluetoothAdapter.isEnabled()) {

Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);

startActivityForResult(enableIntent, REQUEST_ENABLE_BT);

// Otherwise, setup the chat session

} else {

if (mChatService == null) setupChat();

}

}

@Override

public synchronized void onResume() {

super.onResume();

if(D) Log.e(TAG, "+ ON RESUME +");

// Performing this check in onResume() covers the case in which BT was

// not enabled during onStart(), so we were paused to enable it...

// onResume() will be called when ACTION_REQUEST_ENABLE activity returns.

if (mChatService != null) {

// Only if the state is STATE_NONE, do we know that we haven't started already

if (mChatService.getState() == BluetoothChatService.STATE_NONE) {

// Start the Bluetooth chat services

mChatService.start();

}

}

}

private void setupChat() {

Log.d(TAG, "setupChat()");

// Initialize the array adapter for the conversation thread

mConversationArrayAdapter = new ArrayAdapter<String>(this, R.layout.message);

mConversationView = (ListView) findViewById(R.id.in);

mConversationView.setAdapter(mConversationArrayAdapter);

// Initialize the compose field with a listener for the return key

mOutEditText = (EditText) findViewById(R.id.edit_text_out);

mOutEditText.setOnEditorActionListener(mWriteListener);

// Initialize the send button with a listener that for click events

mSendButton = (Button) findViewById(R.id.button_send);

mSendButton.setOnClickListener(new OnClickListener() {

public void onClick(View v) {

// Send a message using content of the edit text widget

TextView view = (TextView) findViewById(R.id.edit_text_out);

String message = view.getText().toString();

sendMessage(message);

}

});

mUploadButton = (Button) findViewById (R.id.upload_button);

mUploadButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

//when upload button is clicked, choose a file

Intent intent = new Intent();

intent.setType("*/*");

intent.setAction(Intent.ACTION_GET_CONTENT);

startActivityForResult(Intent.createChooser(intent, "Select File"),1);

}

});

// Initialize the BluetoothChatService to perform bluetooth connections

mChatService = new BluetoothChatService(this, mHandler);

// Initialize the buffer for outgoing messages

mOutStringBuffer = new StringBuffer("");

}

@Override

public synchronized void onPause() {

super.onPause();

if(D) Log.e(TAG, "- ON PAUSE -");

}

@Override

public void onStop() {

super.onStop();

if(D) Log.e(TAG, "-- ON STOP --");

}

@Override

public void onDestroy() {

super.onDestroy();

// Stop the Bluetooth chat services

if (mChatService != null) mChatService.stop();

if(D) Log.e(TAG, "--- ON DESTROY ---");

}

private void ensureDiscoverable() {

if(D) Log.d(TAG, "ensure discoverable");

if (mBluetoothAdapter.getScanMode() !=

BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {

Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);

discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);

startActivity(discoverableIntent);

}

}

/**

* Sends a message.

* @param message A string of text to send.

*/

private void sendMessage(String message) {

// Check that we're actually connected before trying anything

if (mChatService.getState() != BluetoothChatService.STATE_CONNECTED) {

Toast.makeText(this, R.string.not_connected, Toast.LENGTH_SHORT).show();

return;

}

// Check that there's actually something to send

if (message.length() > 0) {

// Get the message bytes and tell the BluetoothChatService to write

byte[] send = message.getBytes();

mChatService.write(send);

// Reset out string buffer to zero and clear the edit text field

mOutStringBuffer.setLength(0);

mOutEditText.setText(mOutStringBuffer);

}

}

// The action listener for the EditText widget, to listen for the return key

private TextView.OnEditorActionListener mWriteListener =

new TextView.OnEditorActionListener() {

public boolean onEditorAction(TextView view, int actionId, KeyEvent event) {

// If the action is a key-up event on the return key, send the message

if (actionId == EditorInfo.IME_NULL && event.getAction() == KeyEvent.ACTION_UP) {

String message = view.getText().toString();

sendMessage(message);

}

if(D) Log.i(TAG, "END onEditorAction");

return true;

}

};

// The Handler that gets information back from the BluetoothChatService

private final Handler mHandler = new Handler() {

@Override

public void handleMessage(Message msg) {

switch (msg.what) {

case MESSAGE_STATE_CHANGE:

if(D) Log.i(TAG, "MESSAGE_STATE_CHANGE: " + msg.arg1);

switch (msg.arg1) {

case BluetoothChatService.STATE_CONNECTED:

mTitle.setText(R.string.title_connected_to);

mTitle.append(mConnectedDeviceName);

mConversationArrayAdapter.clear();

break;

case BluetoothChatService.STATE_CONNECTING:

mTitle.setText(R.string.title_connecting);

break;

case BluetoothChatService.STATE_LISTEN:

case BluetoothChatService.STATE_NONE:

mTitle.setText(R.string.title_not_connected);

break;

}

break;

case MESSAGE_WRITE:

byte[] writeBuf = (byte[]) msg.obj;

// construct a string from the buffer

String writeMessage = new String(writeBuf);

mConversationArrayAdapter.add("Me: " + writeMessage);

break;

case MESSAGE_READ:

byte[] readBuf = (byte[]) msg.obj;

// construct a string from the valid bytes in the buffer

String readMessage = new String(readBuf, 0, msg.arg1);

mConversationArrayAdapter.add(mConnectedDeviceName+": " + readMessage);

break;

case MESSAGE_DEVICE_NAME:

// save the connected device's name

mConnectedDeviceName = msg.getData().getString(DEVICE_NAME);

Toast.makeText(getApplicationContext(), "Connected to "

+ mConnectedDeviceName, Toast.LENGTH_SHORT).show();

break;

case MESSAGE_TOAST:

Toast.makeText(getApplicationContext(), msg.getData().getString(TOAST),

Toast.LENGTH_SHORT).show();

break;

}

}

};

public void onActivityResult(int requestCode, int resultCode, Intent data) {

if(D) Log.d(TAG, "onActivityResult " + resultCode);

switch (requestCode) {

case REQUEST_CONNECT_DEVICE_SECURE:

// When DeviceListActivity returns with a device to connect

if (resultCode == Activity.RESULT_OK) {

connectDevice(data, true);

}

break;

case REQUEST_CONNECT_DEVICE_INSECURE:

// When DeviceListActivity returns with a device to connect

if (resultCode == Activity.RESULT_OK) {

connectDevice(data, false);

}

break;

case REQUEST_ENABLE_BT:

// When the request to enable Bluetooth returns

if (resultCode == Activity.RESULT_OK) {

// Bluetooth is now enabled, so set up a chat session

setupChat();

} else {

// User did not enable Bluetooth or an error occured

Log.d(TAG, "BT not enabled");

Toast.makeText(this, R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show();

finish();

}

}

}

private void connectDevice(Intent data, boolean secure) {

// Get the device MAC address

String address = data.getExtras()

.getString(DeviceListActivity.EXTRA_DEVICE_ADDRESS);

// Get the BLuetoothDevice object

BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);

// Attempt to connect to the device

mChatService.connect(device, secure);

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

MenuInflater inflater = getMenuInflater();

inflater.inflate(R.menu.option_menu, menu);

return true;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

Intent serverIntent = null;

switch (item.getItemId()) {

case R.id.secure_connect_scan:

// Launch the DeviceListActivity to see devices and do scan

serverIntent = new Intent(this, DeviceListActivity.class);

startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE_SECURE);

return true;

case R.id.discoverable:

// Ensure this device is discoverable by others

ensureDiscoverable();

return true;

}

return false;

}

}