Trung Nguyen Huu Trung Nguyen Huu - 1 month ago 11
Android Question

Crash when starting activity

i am coding an android app. The app begins at the main screen then click the button to go the activity. My code does not have any error and build fine. However launching the app and click the button result in a crash.

My Manifest.XML

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidbtcontrol">
<uses-permission android:name="android.permission.BLUETOOTH" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".bluetoothconnect">
<intent-filter>
<action android:name="com.example.androidbtcontrol.bluetoothconnect" />

<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>

</application>

</manifest>


MainActivity.java

public void OnclickButtonListener(){
button_1 = (Button)findViewById(R.id.button);
button_1.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent("com.example.androidbtcontrol.bluetoothconnect");
startActivity(intent);
}
}
);
}
}


bluetoothconnect.java

public class bluetoothconnect extends AppCompatActivity {

protected void onCreate3(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bluetoothconnect);
}
private static final int REQUEST_ENABLE_BT = 1;

BluetoothAdapter bluetoothAdapter;

ArrayList<BluetoothDevice> pairedDeviceArrayList;

TextView textInfo, textStatus;
ListView listViewPairedDevice;
RelativeLayout inputPane;

SeekBar barAnalogOut;

ArrayAdapter<BluetoothDevice> pairedDeviceAdapter;
private UUID myUUID;
private final String UUID_STRING_WELL_KNOWN_SPP =
"00001101-0000-1000-8000-00805F9B34FB";

ThreadConnectBTdevice myThreadConnectBTdevice;
ThreadConnected myThreadConnected;


protected void onCreate2(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

textInfo = (TextView)findViewById(R.id.info);
textStatus = (TextView)findViewById(R.id.status);
listViewPairedDevice = (ListView)findViewById(R.id.pairedlist);

inputPane = (RelativeLayout) findViewById(R.id.inputpane);

if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH)){
Toast.makeText(this,
"FEATURE_BLUETOOTH NOT support",
Toast.LENGTH_LONG).show();
finish();
return;
}

//using the well-known SPP UUID
myUUID = UUID.fromString(UUID_STRING_WELL_KNOWN_SPP);

bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
Toast.makeText(this,
"Bluetooth is not supported on this hardware platform",
Toast.LENGTH_LONG).show();
finish();
return;
}

String stInfo = bluetoothAdapter.getName() + "\n" +
bluetoothAdapter.getAddress();
textInfo.setText(stInfo);

barAnalogOut = (SeekBar)findViewById(R.id.analogOut);
barAnalogOut.setOnSeekBarChangeListener(OnAnalogOutChangeListener);

}

SeekBar.OnSeekBarChangeListener OnAnalogOutChangeListener =
new SeekBar.OnSeekBarChangeListener(){
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
//will generate too much data sent!
//SendAnalogOut(progress);
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {

}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
SendAnalogOut(seekBar.getProgress());
}
};

private final byte SYNC_BYTE = (byte) 0xAA;
private final byte LENGTH_ANALOG = (byte) 3;
private final byte CMD_ANALOG = (byte) 1;

private void SendAnalogOut(int val){
byte[] bytesToSend = {SYNC_BYTE, LENGTH_ANALOG, CMD_ANALOG, (byte) val};
myThreadConnected.write(bytesToSend);
}

@Override
protected void onStart() {
super.onStart();

//Turn ON BlueTooth if it is OFF
if (!bluetoothAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
}

setup();
}

private void setup() {
Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
pairedDeviceArrayList = new ArrayList<BluetoothDevice>();

for (BluetoothDevice device : pairedDevices) {
pairedDeviceArrayList.add(device);
}

pairedDeviceAdapter = new ArrayAdapter<BluetoothDevice>(this,
android.R.layout.simple_list_item_1, pairedDeviceArrayList);
listViewPairedDevice.setAdapter(pairedDeviceAdapter);

listViewPairedDevice.setOnItemClickListener(new AdapterView.OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
BluetoothDevice device =
(BluetoothDevice) parent.getItemAtPosition(position);
Toast.makeText(bluetoothconnect.this,
"Name: " + device.getName() + "\n"
+ "Address: " + device.getAddress() + "\n"
+ "BondState: " + device.getBondState() + "\n"
+ "BluetoothClass: " + device.getBluetoothClass() + "\n"
+ "Class: " + device.getClass(),
Toast.LENGTH_LONG).show();

textStatus.setText("start ThreadConnectBTdevice");
myThreadConnectBTdevice = new ThreadConnectBTdevice(device);
myThreadConnectBTdevice.start();
}
});
}
}

@Override
protected void onDestroy() {
super.onDestroy();

if(myThreadConnectBTdevice!=null){
myThreadConnectBTdevice.cancel();
}
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(requestCode==REQUEST_ENABLE_BT){
if(resultCode == Activity.RESULT_OK){
setup();
}else{
Toast.makeText(this,
"BlueTooth NOT enabled",
Toast.LENGTH_SHORT).show();
finish();
}
}
}

//Called in ThreadConnectBTdevice once connect successed
//to start ThreadConnected
private void startThreadConnected(BluetoothSocket socket){

myThreadConnected = new ThreadConnected(socket);
myThreadConnected.start();
}

/*
ThreadConnectBTdevice:
Background Thread to handle BlueTooth connecting
*/
private class ThreadConnectBTdevice extends Thread {

private BluetoothSocket bluetoothSocket = null;
private final BluetoothDevice bluetoothDevice;


private ThreadConnectBTdevice(BluetoothDevice device) {
bluetoothDevice = device;

try {
bluetoothSocket = device.createRfcommSocketToServiceRecord(myUUID);
textStatus.setText("bluetoothSocket: \n" + bluetoothSocket);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

@Override
public void run() {
ToggleButton toggle = (ToggleButton) findViewById(R.id.toggleButton);
toggle.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
SendAnalogOut( 0);
// The toggle is enabled
} else {
SendAnalogOut( 255);
// The toggle is disabled
}
}
});
boolean success = false;
try {
bluetoothSocket.connect();
success = true;
} catch (IOException e) {
e.printStackTrace();

final String eMessage = e.getMessage();
runOnUiThread(new Runnable() {

@Override
public void run() {
textStatus.setText("Something wrong BluetoothSocket.connect(): \n" + eMessage);
}
});

try {
bluetoothSocket.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}

if(success){
//connect successful
final String msgconnected = "Connect Successful:\n"
+ "BluetoothSocket: " + bluetoothSocket + "\n"
+ "BluetoothDevice: " + bluetoothDevice;

runOnUiThread(new Runnable(){

@Override
public void run() {
textStatus.setText(msgconnected);

listViewPairedDevice.setVisibility(View.GONE);
inputPane.setVisibility(View.VISIBLE);
}});

startThreadConnected(bluetoothSocket);
}else{
//fail
}
}

public void cancel() {

Toast.makeText(getApplicationContext(),
"close bluetoothSocket",
Toast.LENGTH_LONG).show();

try {
bluetoothSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}

/*
ThreadConnected:
Background Thread to handle Bluetooth data communication
after connected
*/
private class ThreadConnected extends Thread {
private final BluetoothSocket connectedBluetoothSocket;
private final InputStream connectedInputStream;
private final OutputStream connectedOutputStream;

public ThreadConnected(BluetoothSocket socket) {
connectedBluetoothSocket = socket;
InputStream in = null;
OutputStream out = null;

try {
in = socket.getInputStream();
out = socket.getOutputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

connectedInputStream = in;
connectedOutputStream = out;
}

@Override
public void run() {
byte[] buffer = new byte[1024];
int bytes;

while (true) {
try {
bytes = connectedInputStream.read(buffer);
String strReceived = new String(buffer, 0, bytes);
final String msgReceived = String.valueOf(bytes) +
" bytes received:\n"
+ strReceived;

runOnUiThread(new Runnable() {

@Override
public void run() {
textStatus.setText(msgReceived);

}});

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();

final String msgConnectionLost = "Connection lost:\n"
+ e.getMessage();
runOnUiThread(new Runnable(){

@Override
public void run() {
textStatus.setText(msgConnectionLost);
}});
}
}
}

public void write(byte[] buffer) {
try {
connectedOutputStream.write(buffer);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

public void cancel() {
try {
connectedBluetoothSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

}


Main Layout:

<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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity">

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="Please Choose "
android:textStyle="bold" />

<Button
android:text="Button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/button" />
</LinearLayout>


Activity Layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_bluetoothconnect"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.androidbtcontrol.bluetoothconnect">
<TextView
android:id="@+id/info"
android:textStyle="bold|italic"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

<TextView
android:id="@+id/status"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

<ListView
android:id="@+id/pairedlist"
android:layout_width="match_parent"
android:layout_height="match_parent"/>

<RelativeLayout
android:id="@+id/inputpane"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:visibility="gone">
</RelativeLayout>

<SeekBar
android:id="@+id/analogOut"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:max="99"
android:progress="0"/>

<ToggleButton
android:text="ToggleButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/toggleButton" />


</RelativeLayout>

Answer

These are some of the mistakes I can spot from the information you have given. Post the logcat exception details so that I can refine on this solution.

1) Don't use your own version of onCreate (in bluetoothactivity). An activity should have only one onCreate method. You also need to add the @Override prefix to the onCreate method. The code you have contains onCreate2 and onCreate3 methods which are erroneous. That may be the reason for the crash, since when the bluetooth activity is called, it can't find the onCreate method.

 @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

   //Keep your bluetooth related functionality here.


}

2) When launching your intent, you need to specify the source and the destination too.

Intent intent = new Intent(CallingActivity.this,CalledActivity.class);
startActivity(intent);