• RaspberryPi

    Cross-compilation Qt 5.9.6 for RaspberryPi

    Persiapan Raspberry Pi

    Update package

    Edit sources list /etc/apt/sources.list, kemudian uncomment baris deb-src:

    sudo nano /etc/apt/sources.list
    sudo apt-get update
    sudo apt-get dist-upgrade
    sudo reboot

    Update Raspberry Pi firmware

    sudo rpi-update
    sudo reboot

    Install dependencies

    sudo apt-get build-dep qt4-x11
    sudo apt-get build-dep libqt5gui5
    sudo apt-get install libudev-dev libinput-dev libts-dev libxcb-xinerama0-dev libxcb-xinerama0

    Persiapan Linux Host

    Pada tutorial ini digunakan Ubuntu 16.04 x64.

    Update package

    sudo apt-get update
    sudo apt-get -y upgrade

    Install dependencies

    sudo apt-get install git bison python gperf

    Buat folder kerja

    sudo mkdir /opt/qt5pi
    sudo chown akhal:akhal /opt/qt5pi
    cd /opt/qt5pi

    Clone toolchain

    git clone https://github.com/raspberrypi/tools

    Tambahkan toolchain binary di variabel PATH

    nano ~/.bashrc

    Tambahkan baris berikut:

    export PATH=$PATH:/opt/qt5pi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin

    Download QT Source

    https://download.qt.io/official_releases/qt/5.9/5.9.6/single/qt-everywhere-opensource-src-5.9.6.tar.xz

    Untar QT source

    tar -xvf t-everywhere-opensource-src-5.9.6.tar.xz

    Buat hf configuration

    cp -R qt-everywhere-opensource-src-5.9.6/qtbase/mkspecs/linux-arm-gnueabi-g++ qt-everywhere-opensource-src-5.9.6/qtbase/mkspecs/linux-arm-gnueabihf-g++
    sed -i -e 's/arm-linux-gnueabi-/arm-linux-gnueabihf-/g' qt-everywhere-opensource-src-5.9.6/qtbase/mkspecs/linux-arm-gnueabihf-g++/qmake.conf

    Copy raspberry pi sysroot

    mkdir sysroot sysroot/usr sysroot/opt
    rsync -avz akhal@192.168.1.100:/lib sysroot
    rsync -avz akhal@192.168.1.100:/usr/include sysroot/usr
    rsync -avz akhal@192.168.1.100:/usr/lib sysroot/usr
    rsync -avz akhal@192.168.1.100:/opt/vc sysroot/opt

    Buat symlinks to “missing” libraries

    mv sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0 sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0_backup
    ln -s sysroot/opt/vc/lib/libEGL.so sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0
    mv sysroot/usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0 sysroot/usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0_backup
    ln -s sysroot/opt/vc/lib/libGLESv2.so sysroot/usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0
    ln -s sysroot/opt/vc/lib/libEGL.so sysroot/opt/vc/lib/libEGL.so.1
    ln -s sysroot/opt/vc/lib/libGLESv2.so sysroot/opt/vc/lib/libGLESv2.so.2

    Ganti absolute symlinks dalam bentuk relative symlinks

    wget https://raw.githubusercontent.com/riscv/riscv-poky/master/scripts/sysroot-relativelinks.py
    chmod +x sysroot-relativelinks.py
    ./sysroot-relativelinks.py sysroot

    Buat folder untuk build

    mkdir qt5build
    cd qt5build

    Konfigurasi QT Source

    ../qt-everywhere-opensource-src-5.9.6/configure -opengl es2 -device linux-rasp-pi-g++ -device-option CROSS_COMPILE=arm-linux-gnueabihf- -sysroot /opt/qt5pi/sysroot -prefix /usr/local/qt5pi -opensource -confirm-license -skip qtwebengine -skip qtscript -nomake examples -make libs -v

    Jika muncul error unknown CPU architecture ketika konfigurasi, tambahkan baris -no-use-gold-linker sehingga menjadi:

    ../qt-everywhere-opensource-src-5.9.6/configure -opengl es2 -device linux-rasp-pi-g++ -device-option CROSS_COMPILE=arm-linux-gnueabihf- -sysroot /opt/qt5pi/sysroot -prefix /usr/local/qt5pi -opensource -confirm-license -skip qtwebengine -skip qtscript -nomake examples -make libs -v -no-use-gold-linker

    Make

    Jika konfigurasi sudah selesai, jalankan perintah make.

    make
    make install

    Upload hasil compile ke Raspberry Pi

    cd /opt/qt5pi
    rsync -avz sysroot/usr/local/qt5pi akhal@192.168.1.100:/usr/local

    Konfigurasi Pada QT Creator

    Install QT

    Konfigurasi toolkit

    Buka QT Creator, kemudian pilih option dan tambahkan parameter-parameter berikut:

    • Tools->Options…->Devices->Add
      Generic Linux Device
      Edit host, username, dan password.
    • Tools->Build&Run->Debuggers->Add
      Edit name dan path ( /opt/qt5pi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-gdb )
    • Tools->Compilers->Add->GCC->C
      Edit name dan path ( /opt/qt5pi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-gcc )
    • Tools->Compilers->Add->GCC->C++
      Edit name dan path ( /opt/qt5pi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-g++ )
    • Tools->Qt Versions->Add
      Pilih /opt/qt5pi/sysroot/usr/local/qt5pi/bin/qmake
    • Tools->Kits->Add
      Edit name
      Device type: Generic Linux Device
      Device: raspberry pi device
      Sysroot: Choose /opt/qt5pi/sysroot
      C and C++: Choose prior created raspberry pi compilers
      Debugger: Choose prior created raspberry pi debugger
      Qt version: Choose prior created raspberry pi qt version

    Selesai

  • RaspberryPi

    SSH login as root

    Jika ingin login menggunakan ssh sebagai root pada raspberry pi, perlu mengganti file config untuk sshd.

    • login, kemudian edit file config untuk sshd.
      sudo nano /etc/ssh/sshd_config
    • Cari baris PermitRootLogin prohibit-password, kemudian ganti menjadi PermitRootLogin yes
    • Tutup file & simpan.
    • Reboot
  • Linux

    Configure Static IP Addresses on Ubuntu 18.04 LTS Server

    Untuk mengganti ip pada Ubuntu server 18.04, dapat menggunakan NetPlan. Pertama-tama, lihat network device dengan menggunakan perintah ip addr. Misal yang akan diganti adalah eth0.
    Langkah selanjutnya buat file 01-netcfg.yaml di folder /etc/netplan.

    sudo nano /etc/netplan/01-netcfg.yaml

    Untuk mengganti ip address, tuliskan baris berikut:

    # This file describes the network interfaces available on your system
    # For more information, see netplan(5).
    network:
     version: 2
     renderer: networkd
     ethernets:
       eth0:
         dhcp4: no
         dhcp6: no
         addresses: [192.168.1.2/24]
         gateway4: 192.168.1.1
         nameservers:
           addresses: [8.8.8.8,8.8.4.4]

    Keluar dari editor, kemudian jalankan command berikut ini:

    sudo netplan apply
  • Linux

    Locale Issue on Ubuntu

    Error message:

    perl: warning: Setting locale failed.
    perl: warning: Please check that your locale settings:
            LANGUAGE = (unset),
            LC_ALL = (unset),
            LC_TIME = "id_ID.UTF-8",
            LC_MONETARY = "id_ID.UTF-8",
            LC_ADDRESS = "id_ID.UTF-8",
            LC_TELEPHONE = "id_ID.UTF-8",
            LC_NAME = "id_ID.UTF-8",
            LC_MEASUREMENT = "id_ID.UTF-8",
            LC_IDENTIFICATION = "id_ID.UTF-8",
            LC_NUMERIC = "id_ID.UTF-8",
            LC_PAPER = "id_ID.UTF-8",
            LANG = "en_US.UTF-8"
        are supported and installed on your system.
    perl: warning: Falling back to a fallback locale ("en_US.UTF-8").
    locale: Cannot set LC_ALL to default locale: No such file or directory

    Edit bashrc:

    nano ~/.bashrc

    Tambahkan code berikut:

    export LC_ALL="en_US.UTF-8"
  • Linux

    Fujitsu Touchpad Not Working In Ubuntu 18.04

    Untuk mengatasi masalah touchpad yang tidak berfungsi, dapat dilakukan dengan menambahkan i8042.notimeout i8042.nomux pada grub.
    Edit parameter grub.

    sudo gedit /etc/default/grub

    Edit baris berikut GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" sehingga menjadi:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i8042.notimeout i8042.nomux"

    Update grub:

    sudo update-grub

    Langkah terakhir, reboot system.

  • Android

    Custom ActionBar on Android

    Buat activity untuk ActionBar. Misal saya beri nama custom_actionbar_center.xml.

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:background="@android:color/transparent">
    
        <TextView
            android:id="@+id/title_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:textSize="25sp"
            android:textColor="#fff"
            android:gravity="center"
            android:text="title"
            />
    
        <ImageButton
            android:id="@+id/ibtn_bluetooth"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginRight="15dp"
            android:layout_alignParentRight="true"
            android:foregroundGravity="center"
            android:background="@null"
            android:src="@drawable/ic_settings_white_32dp" />
    
    </RelativeLayout>

    Tambahkan code berikut pada activity

    ActionBar mActionBar = getSupportActionBar();
    assert mActionBar != null;
    mActionBar.setDisplayShowHomeEnabled(false);
    mActionBar.setDisplayShowTitleEnabled(false);
    LayoutInflater mInflater = LayoutInflater.from(this);
    View actionBar = mInflater.inflate(R.layout.custom_actionbar_center, null);
    TextView mTitleTextView = actionBar.findViewById(R.id.title_text);
    mTitleTextView.setText(R.string.app_name);
    mActionBar.setCustomView(actionBar);
    mActionBar.setDisplayShowCustomEnabled(true);
    ((Toolbar) actionBar.getParent()).setContentInsetsAbsolute(0,0);
    

    Jika ingin menghilangkan shadow di bawah ActionBar, tambahkan code berikut pada activity:

    getSupportActionBar().setElevation(0);
  • Linux

    How to Fix Time Differences in Ubuntu 16.04 and Windows 10 Dual Boot

    Untuk mengatasi masalah perbedaan waktu ketika dual boot antara ubuntu dan windows, dapat dilakukan dengan cara menonaktifkan UTC dan menggunakan local time. Berikut adalah langkah-langkahnya:

    • Buka terminal, kemudian jalankan command berikut:
      timedatectl set-local-rtc 1 --adjust-system-clock
    • Cek apakah sudah berubah menjadi local time, dengan menggunakan command berikut:
      timedatectl
    • reboot
  • Linux

    Schedule a Nightly Reboot

    Untuk membuat penjadwalan reboot secara otomatis, dapat menggunakan crontab.

    1. Edit crontab.
      sudo crontab -e
    2. Tambahkan line seperti berikut ini:
      0 1 * * *    /sbin/shutdown -r +0

      Server akan reboot secara otomatis setiap jam 1 malam.
      Untuk penjelasannya sebagai berikut:

      m h dom mon dow command
      minute hour dayOfMonth Month dayOfWeek commandToRun
    3. Reboot