Generate javadoc using gradle

In your build.gradle file, adding the below snipet of code can generate the java doc of your module

configurations {

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile "com.android.support:support-annotations:${rootProject.ext.androidSupportSdkVersion}"    javadocDeps "com.android.support:support-annotations:${rootProject.ext.androidSupportSdkVersion}"}

task generateJavadocs(type: Javadoc) {
    source = android.sourceSets.main.java.srcDirs
    classpath += project.files(android.getBootClasspath()

    classpath += configurations.javadocDeps    failOnError false    destinationDir = file("../javaDoc/")
    exclude {


Auto-generating enum/constants for different languages like c++, java, python, and so on

  In the past, speaking of cross-language tools to serialize and auto-generate structured data, you might use Protobuf to do that, Recently, I start to use flatbuffers to serialize/deserialize and auto-generate my data structure. There are a lot of comparisons on Protobuf, json, and flatbuffers, you can refer to the below links:
Why consider flatbuffer over json
How much is flatbuffer faster protobuf
Primay differences between protbuf and flatbuffers

Today, I am going to demonstrate how to use flatbuffers to auto-generate enum/constants for different languages like c++, java, python, and so on.

Clone flatbuffers
git clone https://github.com/google/flatbuffers
cd flatbuffers
Depending on your platform, use one of e.g.
$ cmake -G "Unix Makefiles"
$ cmake -G "Visual Studio 10"
$ cmake -G "Xcode"
Start to build
$ make
After making it, there is one of executable files, called flatc. Now, we can use flatc to genereate different source files for different language using flatbuffers's interface definition language(IDL).

Create an IDL file
vi resultcode.fbs
namespace tzutalin.common;
enum ResultCode { SUCCESS = 0, TIME_OUT, UNKNOWN_ERROR }
Use the below command to generate its c++ header, python, and Java file.
$ ./flatc --cpp --python --java -b resultcode.fbs

After generating, it creates ./resultcode_generated.h, ./tzutalin/common/ResultCode.py, and ./tzutalin/common/ResultCode.java.

// automatically generated by the FlatBuffers compiler, do not modify
#include "flatbuffers/flatbuffers.h"
namespace tzutalin {
namespace common {
enum ResultCode {
  ResultCode_SUCCESS = 0,
  ResultCode_TIME_OUT = 1,
  ResultCode_UNKNOWN_ERROR = 2,
  ResultCode_MIN = ResultCode_SUCCESS,
  ResultCode_MAX = ResultCode_UNKNOWN_ERROR
inline const char **EnumNamesResultCode() {
  static const char *names[] = { "SUCCESS", "TIME_OUT", "UNKNOWN_ERROR", nullptr };
  return names;
inline const char *EnumNameResultCode(ResultCode e) { return EnumNamesResultCode()[static_cast<int>(e)]; }
}  // namespace common
}  // namespace tzutalin
# automatically generated by the FlatBuffers compiler, do not modify
# namespace: common
class ResultCode(object):
    SUCCESS = 0
    TIME_OUT = 1
// automatically generated by the FlatBuffers compiler, do not modify
package tzutalin.common;
public final class ResultCode {
  private ResultCode() { }
  public static final byte SUCCESS = 0;
  public static final byte TIME_OUT = 1;
  public static final byte UNKNOWN_ERROR = 2;
  public static final String[] names = { "SUCCESS", "TIME_OUT", "UNKNOWN_ERROR", };
  public static String name(int e) { return names[e]; }


Restore missing tools/status/menu bar in Ubuntu 16.04

  Recently, I upgraded my Ubuntu from 14.04 to 16.04. It works well after upgrading. But someday my toolbar and menu bar are missing after I updating some packages and rebooting. Then, I try to enable Unity Launcher again, my toolbar and menu are back. The below steps are what I do

1. $ sudo apt install compizconfig-settings-manager
2. $ ccsm
3. Enable Ubuntu Unity Plugin. It will ask some questions because enabling it conflicts with another one.