Gson (on Android Studio)

Why I met with Gson?

While I was try to store one whole complex object into SharedPerference in Android code, I found that it's default basic data types are not supporting. Also, it's hard to decode them in to json string unless I am writing it's custom encoding function.

Then, I found people are solving this problem using Gson on StackOverflow.

• http://stackoverflow.com/questions/5418160/store-and-retrieve-a-class-object-in-shared-preference
• http://stackoverflow.com/questions/7145606/how-android-sharedpreferences-save-store-object
• http://stackoverflow.com/questions/14501146/how-to-store-class-object-in-android-sharedpreference

Intro for Gson

"Gson is a Java library that can be used to convert Java Objects into their JSON representation."

Install Gson on Android Studio

Follow the top answer in this StackOverflow thread.

Usage

https://sites.google.com/site/gson/gson-user-guide#TOC-Object-Examples

Menu Collapses when Using PageViewer (Action Bar Tabs)

寫Android App時，使用viewpager會在actionbar上頭產生tab，而如果使用R.menu內的xml檔案，我們可以在右上角產生action button，但我發現他們都疊在一起了(collapse)，根據文件，應該在設定成ifRoom之後在有空間情況下會直接出現在action bar而非下拉選單。

於是我上網找詢問解決方法，得到以下：

在tag設定上，我們應該注意showAsAction前的namespace應該用一個同於第二行xmlns底下的名稱。相同之後問題就解決了！

Reference

• Android Official Document
• [stackoverflow] Android use namespace as prefix for attributes in library