So i tried googling it and found some suggestions like disabling all plugins and tried to downgrade the wordpress version. I tried those suggestions but nothing worked.

There was a suggestion to disable the Guttenberg editor by installing Disable Guttenberg plugin. I tried it and it worked like a charm.  The conflict was caused by WordPress 5.6 updated Gutenberg editor with our theme’s visual editor.

So here the step steps:

• Go to Plugin page and search for Disable Guttenberg plugin
• Install and activate the plugin
• The blank screen issue will disapear.

Hope it helps.

The post How to Fix Blank Screen on WordPress Add/Edit Post Page appeared first on Lorenz Blog.

Below is the code to restart the board:

esp_task_wdt_init(1,true);
esp_task_wdt_add(NULL);

while(true);

Also include these two header files:

#include <esp_int_wdt.h>
#include <esp_task_wdt.h>

The post How to Programmatically Restart the ESP32 Board appeared first on Lorenz Blog.

Sometimes we need to get hardware info from each board we develop, either to show it to user or just show them on log messages. On Esp32, to get the hardware info, use the following code:

    esp_chip_info_t chip_info;
    esp_chip_info(&chip_info);

    Serial.println("Hardware info");
    Serial.printf("%d cores Wifi %s%s\n", chip_info.cores, (chip_info.features & CHIP_FEATURE_BT) ? "/BT" : "",
     (chip_info.features & CHIP_FEATURE_BLE) ? "/BLE" : "");
    Serial.printf("Silicon revision: %d\n", chip_info.revision);
    Serial.printf("%dMB %s flash\n", spi_flash_get_chip_size()/(1024*1024),
    (chip_info.features & CHIP_FEATURE_EMB_FLASH) ? "embeded" : "external");

    //get chip id
    chipId = String((uint32_t)ESP.getEfuseMac(), HEX);
    chipId.toUpperCase();

    Serial.printf("Chip id: %s\n", chipId.c_str());

Don’t forget to include the ESP.h header file. Happy coding!

The post How to Get Hardware Info of ESP32 appeared first on Lorenz Blog.

WebSocket connection to ‘ws://123.11.11.11:8883/mqtt’ failed: Connection closed before receiving a handshake response

The above error message was from javascript library when i tried to connect MQTT server that didn’t support websocket. My previous MQTT server was installed with Mosquitto running on Freebsd and it worked well with standard MQTT connection. The standard installation of Mosquitto didn’t support websocket so i had to install additional libwebsocket library and recompiled the Mosquitto.

So here are the requirements and steps to upgrade or setup MQTT server with websocket support using Mosquitto on a FreeBSD server:

Requirements:

• Mosquitto 1.6.2,   (latest stable version )
• Libwebsocket-2.4.2, (latest stable version)

Installation:

Libwebsocket

Install libwebsocket from Freebsd ports

#cd /usr/ports/net/libwebsockets

Check the version (2.4.2) (view the distinfo file), if you have old version then backup the libwebsockets port directory

#mv libwebsockets libwebsockets.old

Download and extract the libwebsocket port file

#wget http://www.londatiga.net/downloads/iot/libwebsockets-ports-2.4.2.tar.gz
#tar -xzvf libwebsockets-ports-2.4.2.tar.gz
#cd libwebsockets

Compile and install

#make
#make install

If installation succes, make sure these files exist:

/usr/local/lib/libwebsockets.so
/usr/local/lib/libwebsockets.so.12
/usr/local/include/libwebsockets.h

Mosquitto

Download and extract the source file

#wget https://mosquitto.org/files/source/mosquitto-1.6.2.tar.gz
#tar -xzvf mosquitto-1.6.2.tar.gz
#cd mosquitto-1.6.2

Edit config.mk file to enable websocket. Replace the line WITH_WEBSOCKETS:=no with WITH_WEBSOCKETS:=yes

Copy libwebsocket header files into src directory

#cp /usr/local/include/libwebsockets.h src
#cp /usr/local/include/lws_config.h src
#cp /usr/local/include/uv* src
#cp /usr/local/include/ev.h src

#gmake
#gmake install

Troubleshouting:

You may find some errors while compiling and installing mosquitto, here are some issues:

Issues with openssl:

This issue due to incompatible openssl version, mosquitto 1.6.2 requires openssl >= 1.0.2, so you may get this error messages while compiling:

../lib/libmosquitto.so.1: undefined reference to `SSL_CTX_set_alpn_protos

The solution is to lower the version of mosquitto, you can use version 1.5.8.

Issues with linking dynamic library lwebsockets

/usr/bin/ld: cannot find -lwebsockets

This issue due to the compiler doesn’t find the libwebsockets.so shared library, the solution is to create symbolic link from /usr/local/lib/libwebsockets.so to /lib/libwebsockets.so

#ln -s /usr/local/lib/libwebsockets.so /lib/libwebsockets.so

Issues while installing (gmake install)

install -m644 ../libmosquitto.pc.in “/usr/local/lib/pkgconfig/libmosquitto.pc”
sed -i -e “s#@CMAKE_INSTALL_PREFIX@#/usr/local#” -e “s#@VERSION@#1.5.8#” “/usr/local/lib/pkgconfig/libmosquitto.pc”
sed: -e: No such file or directory

This issue due to invalid sed -e command while trying to replace the CMAKE_INSTALL_PREFIX and VERSION on /usr/local/lib/pkgconfig/libmosquitto.pc file. I’m not expert on sed command, so my solution is to edit this two files two Makefiles:

• lib/Makefile
• lib/cpp/Makefile

find this line:

sed -i -e “s#@CMAKE_INSTALL_PREFIX@#${prefix}#” -e “s#@VERSION@#${VERSION}#” “${DESTDIR}${libdir}/pkgconfig/libmosquitto.pc”

Remove the -e “s#@CMAKE_INSTALL_PREFIX@#${prefix}#”  section so the result would be:

sed -i -e “s#@VERSION@#${VERSION}#” “${DESTDIR}${libdir}/pkgconfig/libmosquitto.pc”

Then run #gmake install again and after successfully installing, don’t forget to update the /usr/local/lib/pkgconfig/libmosquitto.pc file, replace the @CMAKE_INSTALL_PREFIX@ with /usr/local.

Setting up Mosquitto

Create a user to run mosquitto, we use mosquitto as the username with nologin and nonexistent options.

#adduser
Username: mosquitto
Full name: Mosquitto MQTT Broker
…..
Shell (sh csh tcsh git-shell nologin) [sh]: nologin
Home directory [/home/mosquitto]: /nonexistent

Change ownership of the directory /var/lib/mosquitto/mosquitto.db to mosquitto (if not exist, create new one)

#chown mosquitto /var/lib/mosquitto/mosquitto.db

Create a file log /var/log/mosquitto.log

#touch /var/log/mosquitto.log
#chown mosquitto /var/log/mosquitto.log

Create http dir for websocket

#mkdir /var/lib/mosquitto/http_dir
#chown mosquitto /var/lib/mosquitto/http_dir

Create username and password for MQTT authentication

#mosquitto_passwd -c /etc/mosquitto/pwfile lorenz
Password:
Reenter password:

Replace the ‘lorenz‘ with your username.

Create the configuration file /etc/mosquitto/mosquitto.conf and use the following configuration

listener 9001 xx.xx.xx.xx
protocol websockets
socket_domain ipv4
http_dir /var/lib/mosquitto/http_dir
listener 8883 xx.xx.xx.xx
protocol mqtt
persistence_location /var/lib/mosquitto/
persistence_file mosquitto.db
log_dest syslog
log_dest stdout
log_dest topic
log_dest file /var/log/mosquitto.log
log_type error
log_type warning
log_type notice
log_type information
connection_messages true
log_timestamp true
allow_anonymous false
password_file /etc/mosquitto/pwfile
user mosquitto

Here, we use port 9001 for MQTT over websockets and 8883 for standard/native MQTT. Replace the xx.xx.xx.xx with your hostname or ip address. You can use whatever port number as you like as long as the number isn’t being used by other service or application.

Run the mosquitto service

#mosquitto -c /etc/mosquitto/mosquitto.conf

You should see these messages on starting up:

1559210145: mosquitto version 1.5.8 starting
1559210145: Config loaded from /etc/mosquitto/mosquitto.conf.
1559210145: Opening websockets listen socket on port 9001.
1559210145: Opening ipv4 listen socket on port 8883.

Based on the above configuration, you should use port 9001 for connection with javascript library on web browser and 8883 on other devices. The message will be automatically forwarded between those ports. So the message that you send on 8883 will also be received on javascript client on port 9001.

The post How to Setup MQTT Server Using Mosquitto and Libwebsocket on Freebsd appeared first on Lorenz Blog.

The suggested solution is to install Java SE 6 runtime from Apple website  by clicking the More Info button. But because the internet service is expensive here and i don’t want to spend extra internet quota to download the java update,i do some googlings and found an alternative solution.

The solution is simple, just to make some changes the Info.plist file in Java library folder:

• Locate the Info.plist in your JDK folder, mine is under

  /Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/
  

• Edit the Info.plist file using your favorite editor

  $vim /Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Info.plist
  

• Find the following lines

  <key>JVMCapabilities</key>
  <array>
    <string>CommandLine</string>
  </array>
  

• Replace those lines with

  <key>JVMCapabilities</key>
  <array>
    <string>JNI</string>
    <string>BundledApp</string>
    <string>WebStart</string>
    <string>Applets</string>
    <string>CommandLine</string>
  </array>
  

• Restart the OS X so the changes will take effect

Hope it helps.

The post Eclipse Issue on Os X Yosemite – To open “Eclipse” you need to install the legacy Java SE 6 runtime appeared first on Lorenz Blog.

Blue Bamboo also provides a sample Android project to show how to build an application that supports printing using P25 printer over Bluetooth. The source code itself is quite old so i made a slight modification with fresh UI and easy to read source code so developers can easily implement the codes into their projects.

This sample code shows how to print text, image, barcode and receipt into P25 printer using Bluetooth connectivity. The source code is available on Github repo, you can find it at the bottom of this post.

Print Text

private void printText(String text) {
	byte[] line 	= Printer.printfont(text + "\n\n", FontDefine.FONT_32PX, FontDefine.Align_CENTER, (byte) 0x1A, PocketPos.LANGUAGE_ENGLISH);
	byte[] senddata = PocketPos.FramePack(PocketPos.FRAME_TOF_PRINT, line, 0, line.length);

	sendData(senddata);
}

Use Printer.printFont(String content, byte fonttype, byte fontalign,byte linespace, byte language) method to format and position the text. For font types and text alignment, see FontDefine.java and for language definition, see PocketPos.java. Also call the PocketPos.FramePack(byte typeFrame, byte[] srcBuff, int srcOffset, int srcLen) to create frame data before sending to printer.

See P25 development guide page 60-63 for more information.

Print 1D Barcode

private void print1DBarcode() {
	String content	= "6901234567892";

	byte[] formats	= {(byte) 0x1d, (byte) 0x6b, (byte) 0x02, (byte) 0x0d};
	byte[] contents	= content.getBytes();

	byte[] bytes	= new byte[formats.length + contents.length];

	System.arraycopy(formats, 0, bytes, 0, formats.length);
	System.arraycopy(contents, 0, bytes, formats.length, contents.length);

	sendData(bytes);

	byte[] newline 	= Printer.printfont("\n\n",FontDefine.FONT_32PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);

	sendData(newline);
}

1D barcode printing format is: 1d 6b 02 0d [barcode data]. So to print “6901234567892” barcode data, the bytes would be:

{(byte) 0x1d, (byte) 0x6b, (byte) 0x02, (byte) 0x0d}
+
“6901234567892”.getBytes()

See P25 development guide page 59-60 for more information.

Print 2D Barcode

private void print2DBarcode() {
	String content 	= "Lorenz Blog - www.londatiga.net";

	byte[] formats	= {(byte) 0x1d, (byte) 0x6b, (byte) 0x10, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
						  (byte) 0x00, (byte) 0x1f};
	byte[] contents	= content.getBytes();
	byte[] bytes	= new byte[formats.length + contents.length];

	System.arraycopy(formats, 0, bytes, 0, formats.length);
	System.arraycopy(contents, 0, bytes, formats.length, contents.length);

	sendData(bytes);

	byte[] newline 	= Printer.printfont("\n\n",FontDefine.FONT_32PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);

	sendData(newline);
}

2D barcode printing format is: 1d 6b 10 00 00 00 00 00 1f + barcode data. So to print “Lorenz Blog – www.londatiga.net” text, the bytes would be:

{(byte) 0x1d, (byte) 0x6b, (byte) 0x10, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x1f}
+
“Lorenz Blog – www.londatiga.net”.getBytes()

See P25 development guide page 60 for more information

Print Image

private void printImage() {
	try {
		byte[] formats	= { (byte)0x1B, (byte)0x58, (byte)0x31, (byte)0x24, (byte)0x2D };

		//bluebamboo logo
		byte[] image = {(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00,(byte)0x00, ....... (byte)0x00};

		sendData(bytes);

		byte[] newline 	= Printer.printfont("\n\n",FontDefine.FONT_32PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);

		sendData(newline);
	} catch (Exception e) {
		e.printStackTrace();
	}
}

Image printing format is: 1B 58 31 xx yy + {image data in bitmap monochrome format} where xx is width in pixels/8 and yy is height of image in pixels.

So to print 200×45 pixels of image, the format would be :

{ (byte)0x1B, (byte)0x58, (byte)0x31, (byte)0x24, (byte)0x2D } + { bytes of bitmap monochrome image}

Width = 200pixels/8bit = 25 in decimals = 0x24 in hexa
Height= 45 pixels in decimal = 0x2D in hexa

See http://bluebamboo.helpserve.com/index.php?/Knowledgebase/Article/View/48 for more information on how to print image and P25 development guide page 18-13 and 63.

Print Sample Receipt

private void printStruk() {
		String titleStr	= "STRUK PEMBAYARAN TAGIHAN LISTRIK" + "\n\n";

		StringBuilder contentSb	= new StringBuilder();

		contentSb.append("IDPEL     : 435353535435353" + "\n");
		contentSb.append("NAMA      : LORENSIUS WLT" + "\n");
		contentSb.append("TRF/DAYA  : 50/12244 VA" + "\n");
		contentSb.append("BL/TH     : 02/14" + "\n");
		contentSb.append("ST/MTR    : 0293232" + "\n");
		contentSb.append("RP TAG    : Rp. 100.000" + "\n");
		contentSb.append("JPA REF   :" + "\n");

		StringBuilder content2Sb = new StringBuilder();

		content2Sb.append("ADM BANK  : Rp. 1.600" + "\n");
		content2Sb.append("RP BAYAR  : Rp. 101.600,00" + "\n");

		String jpaRef	= "XXXX-XXXX-XXXX-XXXX" + "\n";
		String message	= "PLN menyatakan struk ini sebagai bukti pembayaran yang sah." + "\n";
		String message2	= "Rincian tagihan dapat diakses di www.pln.co.id Informasi Hubungi Call Center: "
						+ "123 Atau Hub PLN Terdekat: 444" + "\n";

		long milis		= System.currentTimeMillis();
		String date		= DateUtil.timeMilisToString(milis, "dd-MM-yy / HH:mm")  + "\n\n";

		byte[] titleByte	= Printer.printfont(titleStr, FontDefine.FONT_24PX,FontDefine.Align_CENTER,
								(byte)0x1A, PocketPos.LANGUAGE_ENGLISH);

		byte[] content1Byte	= Printer.printfont(contentSb.toString(), FontDefine.FONT_24PX,FontDefine.Align_LEFT,
								(byte)0x1A, PocketPos.LANGUAGE_ENGLISH);

		byte[] refByte		= Printer.printfont(jpaRef, FontDefine.FONT_24PX,FontDefine.Align_CENTER,  (byte)0x1A,
								PocketPos.LANGUAGE_ENGLISH);

		byte[] messageByte	= Printer.printfont(message, FontDefine.FONT_24PX,FontDefine.Align_CENTER,  (byte)0x1A,
								PocketPos.LANGUAGE_ENGLISH);

		byte[] content2Byte	= Printer.printfont(content2Sb.toString(), FontDefine.FONT_24PX,FontDefine.Align_LEFT,
								(byte)0x1A, PocketPos.LANGUAGE_ENGLISH);

		byte[] message2Byte	= Printer.printfont(message2, FontDefine.FONT_24PX,FontDefine.Align_CENTER,  (byte)0x1A,
								PocketPos.LANGUAGE_ENGLISH);

		byte[] dateByte		= Printer.printfont(date, FontDefine.FONT_24PX,FontDefine.Align_LEFT, (byte)0x1A,
								PocketPos.LANGUAGE_ENGLISH);

		byte[] totalByte	= new byte[titleByte.length + content1Byte.length + refByte.length + messageByte.length +
		                	           content2Byte.length + message2Byte.length + dateByte.length];

		int offset = 0;
		System.arraycopy(titleByte, 0, totalByte, offset, titleByte.length);
		offset += titleByte.length;

		System.arraycopy(content1Byte, 0, totalByte, offset, content1Byte.length);
		offset += content1Byte.length;

		System.arraycopy(refByte, 0, totalByte, offset, refByte.length);
		offset += refByte.length;

		System.arraycopy(messageByte, 0, totalByte, offset, messageByte.length);
		offset += messageByte.length;

		System.arraycopy(content2Byte, 0, totalByte, offset, content2Byte.length);
		offset += content2Byte.length;

		System.arraycopy(message2Byte, 0, totalByte, offset, message2Byte.length);
		offset += message2Byte.length;

		System.arraycopy(dateByte, 0, totalByte, offset, dateByte.length);

		byte[] senddata = PocketPos.FramePack(PocketPos.FRAME_TOF_PRINT, totalByte, 0, totalByte.length);

		sendData(senddata);
}

Print Demo Page

private void printDemoContent(){

		/*********** print head*******/
		String receiptHead = "************************"
				+ "   P25/M Test Print"+"\n"
				+ "************************"
				+ "\n";

		long milis		= System.currentTimeMillis();

		String date		= DateUtil.timeMilisToString(milis, "MMM dd, yyyy");
		String time		= DateUtil.timeMilisToString(milis, "hh:mm a");

		String hwDevice	= Build.MANUFACTURER;
		String hwModel	= Build.MODEL;
		String osVer	= Build.VERSION.RELEASE;
		String sdkVer	= String.valueOf(Build.VERSION.SDK_INT);

		StringBuffer receiptHeadBuffer = new StringBuffer(100);

		receiptHeadBuffer.append(receiptHead);
		receiptHeadBuffer.append(Util.nameLeftValueRightJustify(date, time, DataConstants.RECEIPT_WIDTH) + "\n");

		receiptHeadBuffer.append(Util.nameLeftValueRightJustify("Device:", hwDevice, DataConstants.RECEIPT_WIDTH) + "\n");

		receiptHeadBuffer.append(Util.nameLeftValueRightJustify("Model:",  hwModel, DataConstants.RECEIPT_WIDTH) + "\n");
		receiptHeadBuffer.append(Util.nameLeftValueRightJustify("OS ver:", osVer, DataConstants.RECEIPT_WIDTH) + "\n");
		receiptHeadBuffer.append(Util.nameLeftValueRightJustify("SDK:", sdkVer, DataConstants.RECEIPT_WIDTH));
		receiptHead = receiptHeadBuffer.toString();

		byte[] header = Printer.printfont(receiptHead + "\n", FontDefine.FONT_32PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);

		/*********** print English text*******/
		StringBuffer sb = new StringBuffer();
		for(int i=1; i<128; i++)
			sb.append((char)i);
		String content = sb.toString().trim();

		byte[] englishchartext24 			= Printer.printfont(content + "\n",FontDefine.FONT_24PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);
		byte[] englishchartext32			= Printer.printfont(content + "\n",FontDefine.FONT_32PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);
		byte[] englishchartext24underline	= Printer.printfont(content + "\n",FontDefine.FONT_24PX_UNDERLINE,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);

		//2D Bar Code
		byte[] barcode = StringUtil.hexStringToBytes("1d 6b 02 0d 36 39 30 31 32 33 34 35 36 37 38 39 32");

		/*********** print Tail*******/
		String receiptTail =  "Test Completed" + "\n"
				+ "************************" + "\n";

		String receiptWeb =  "** www.londatiga.net ** " + "\n\n\n";

		byte[] foot = Printer.printfont(receiptTail,FontDefine.FONT_32PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);
		byte[] web	= Printer.printfont(receiptWeb,FontDefine.FONT_32PX,FontDefine.Align_CENTER,(byte)0x1A,PocketPos.LANGUAGE_ENGLISH);

		byte[] totladata =  new byte[header.length + englishchartext24.length + englishchartext32.length + englishchartext24underline.length +
		                              + barcode.length
		                             + foot.length + web.length
		                             ];
	 	int offset = 0;
		System.arraycopy(header, 0, totladata, offset, header.length);
		offset += header.length;

		System.arraycopy(englishchartext24, 0, totladata, offset, englishchartext24.length);
		offset+= englishchartext24.length;

		System.arraycopy(englishchartext32, 0, totladata, offset, englishchartext32.length);
		offset+=englishchartext32.length;

		System.arraycopy(englishchartext24underline, 0, totladata, offset, englishchartext24underline.length);
		offset+=englishchartext24underline.length;

		System.arraycopy(barcode, 0, totladata, offset, barcode.length);
		offset+=barcode.length;

		System.arraycopy(foot, 0, totladata, offset, foot.length);
		offset+=foot.length;

		System.arraycopy(web, 0, totladata, offset, web.length);
		offset+=web.length;

		byte[] senddata = PocketPos.FramePack(PocketPos.FRAME_TOF_PRINT, totladata, 0, totladata.length);

		sendData(senddata);
}

All bytes data to be printed is sent to printer using sendData method from P25Connector class (P25Connector.java)

private void sendData(byte[] bytes) {
	try {
		mConnector.sendData(bytes);
	} catch (P25ConnectionException e) {
		e.printStackTrace();
	}
}

P25Connector is a wrapper class to handle bluetooth operation (connect, disconnect, and bluetooth socket operation)

Demo video

Real life application video

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Download source code from Github repo

The post Blue Bamboo P25 Printer Android Demo Application With Source Code appeared first on Lorenz Blog.

Using Android Bluetooth API, we can use createBond method to pair with a device or removeBond to unpair. This  is an asynchronous call so that it will return immediately. To catch the pairing process, we have to register a BroadcastReceiver with ACTION_BOND_STATE_CHANGED intent to catch the process.

  
(apk and source code at the bottom if this post)

How to pair

private void pairDevice(BluetoothDevice device) {
        try {
            Method method = device.getClass().getMethod("createBond", (Class[]) null);
            method.invoke(device, (Object[]) null);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

How to Unpair

private void unpairDevice(BluetoothDevice device) {
        try {
            Method method = device.getClass().getMethod("removeBond", (Class[]) null);
            method.invoke(device, (Object[]) null);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

The receiver to catch the pairing process:

private final BroadcastReceiver mPairReceiver = new BroadcastReceiver() {
	    public void onReceive(Context context, Intent intent) {
	        String action = intent.getAction();

	        if (BluetoothDevice.ACTION_BOND_STATE_CHANGED.equals(action)) {
	        	 final int state 		= intent.getIntExtra(BluetoothDevice.EXTRA_BOND_STATE, BluetoothDevice.ERROR);
	        	 final int prevState	= intent.getIntExtra(BluetoothDevice.EXTRA_PREVIOUS_BOND_STATE, BluetoothDevice.ERROR);

	        	 if (state == BluetoothDevice.BOND_BONDED && prevState == BluetoothDevice.BOND_BONDING) {
	        		 showToast("Paired");
	        	 } else if (state == BluetoothDevice.BOND_NONE && prevState == BluetoothDevice.BOND_BONDED){
	        		 showToast("Unpaired");
	        	 }

	        }
	    }
	};

Register receiver

IntentFilter intent = new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
registerReceiver(mPairReceiver, intent);

For each changed state, the intent will carry extra fields EXTRA_BOND_STATE and EXTRA_PREVIOUS_BOND_STATE. Using the value from the  extra fields we can determine the state of pairing process.

State paired if current state is BOND_BONDED and previous state is BOND_BONDING.
State unpaired if current state is BOND_NONE and previous state is BOND_BONDED.

Download the sample APK and source code from github

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The post How to Programmatically Pair or Unpair Android Bluetooth Device appeared first on Lorenz Blog.

(apk + source code at the bottom of this post)

To discover a device, first get the bluetooth adapter by calling BluetoothAdapter.getDefaultAdapter(). 

BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();

To start discover, simply call the startDiscovery() from bluetooth adapter. This process is asynchronous so it will return immediately. To catch the discovery process, we can register a BroadcastReceiver with ACTION_FOUND,  ACTION_DISCOVERY_STARTED,  ACTION_DISCOVERY_STARTED. For each device found, the intent will carry extra field  EXTRA_DEVICE containg the BluetoothDevice object.

IntentFilter filter = new IntentFilter();

filter.addAction(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);

registerReceiver(mReceiver, filter);
adapter.startDiscovery();

The receiver:

private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
	    public void onReceive(Context context, Intent intent) {
	        String action = intent.getAction();

	        if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
	        	//discovery starts, we can show progress dialog or perform other tasks
	        } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
	        	//discovery finishes, dismis progress dialog
	        } else if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                       //bluetooth device found
	        	BluetoothDevice device = (BluetoothDevice) intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

	        	showToast("Found device " + device.getName());
	        }
	    }
	};

And, don’t forget to unregister the receiver on Activity’s onDestroy method:

@Override
	public void onDestroy() {
		unregisterReceiver(mReceiver);

		super.onDestroy();
	}

Download the sample APK and source code from github

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The post How to Programmatically Scan or Discover Android Bluetooth Devices appeared first on Lorenz Blog.

This is hack i found on stackoverflow, from Neil Traft ‘s answer:

ExpandableHeightListView

package net.londatiga.android.widget;

import android.util.AttributeSet;
import android.view.ViewGroup;
import android.widget.ListView;
import android.content.Context;

public class ExpandableHeightListView extends ListView
{

boolean expanded = false;

public ExpandableHeightListView(Context context)
    {
        super(context);
    }

    public ExpandableHeightListView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
    }

    public ExpandableHeightListView(Context context, AttributeSet attrs,
            int defStyle)
    {
        super(context, attrs, defStyle);
    }

    public boolean isExpanded()
    {
        return expanded;
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        // HACK! TAKE THAT ANDROID!
        if (isExpanded())
        {
            // Calculate entire height by providing a very large height hint.
            // But do not use the highest 2 bits of this integer; those are
            // reserved for the MeasureSpec mode.
            int expandSpec = MeasureSpec.makeMeasureSpec(
                    Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
            super.onMeasure(widthMeasureSpec, expandSpec);

            ViewGroup.LayoutParams params = getLayoutParams();
            params.height = getMeasuredHeight();
        }
        else
        {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        }
    }

    public void setExpanded(boolean expanded)
    {
        this.expanded = expanded;
    }
}

ExpandableHeightGridView

package net.londatiga.android.widget;

import android.util.AttributeSet;
import android.view.ViewGroup;
import android.widget.GridView;
import android.content.Context;

public class ExpandableHeightGridView extends GridView
{

 boolean expanded = false;

 public ExpandableHeightGridView(Context context)
 {
 super(context);
 }

 public ExpandableHeightGridView(Context context, AttributeSet attrs)
 {
 super(context, attrs);
 }

 public ExpandableHeightGridView(Context context, AttributeSet attrs,
 int defStyle)
 {
 super(context, attrs, defStyle);
 }

 public boolean isExpanded()
 {
 return expanded;
 }

 @Override
 public void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
 {
 // HACK! TAKE THAT ANDROID!
 if (isExpanded())
 {
 // Calculate entire height by providing a very large height hint.
 // But do not use the highest 2 bits of this integer; those are
 // reserved for the MeasureSpec mode.
 int expandSpec = MeasureSpec.makeMeasureSpec(
 Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
 super.onMeasure(widthMeasureSpec, expandSpec);

 ViewGroup.LayoutParams params = getLayoutParams();
 params.height = getMeasuredHeight();
 }
 else
 {
 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 }
 }

 public void setExpanded(boolean expanded)
 {
 this.expanded = expanded;
 }
}

How to use:

//ListView
ExpandableHeightListView listView = new ExpandableHeightListView(this);

listView.setAdapter(adapter);
listView.setExpanded(true);

//GridView
ExpandableHeightGridView gridView = new ExpandableHeightGridView(this);

gridView.setNumColumns(4);
gridView.setAdapter(adapter);
gridView.setExpanded(true);

As you can see, to make the ListView or GridView expandable, just call the setExapanded(true).

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The post How to Make Android ListView or GridView Expandable inside ScrollView appeared first on Lorenz Blog.

• BBM Voice – Free voice calls between BBM contacts (Android, Blackberry, Iphone)
• BBM Channels – join conversations happening now with BBM users, brands, businesses, communities and more
• Faster and easier sharing,
• Dropbox integration
• Larger BBM groups, up to 50 users
• Tons of new emoticons

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The post New BBM for Android V2.0 is Out, Brings Channels, Voice, Location Sharing, Tons of New Emoticons, Larger Groups and More appeared first on Lorenz Blog.