在Android開發中,我們使用android.util.Log來打印日誌,方便我們的開發調試。但是這些代碼不想在發佈後執行,我們並不想在軟件發佈後調試日誌被其他開發者看到,現在我的方法是設置一個全局變量,標記軟件爲Debug模式還是Release模式。來看下代碼:
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">1</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">2</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">3</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">4</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">5</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">6</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">7</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">8</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">9</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">10</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">11</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">12</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">13</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">14</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">15</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">16</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">17</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">18</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">19</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">20</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">21</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">22</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">23</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">24</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">25</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">26</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">27</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">28</span> |
|
這樣打包發佈之前只要改下DEBUG=false就行了,但是每次在發佈之前都要手動去改這個變量,不是很方便,而且不排除開發者忘記改的情況。那麼有沒有更好更方便的做法呢?
ADT(r17)發佈以後,Google爲我們提供了一種新的調試機制,即BuildConfig.DEBUG。
ADT 17.0.0的New build features第二條如下描述:
Added a feature that allows you to run some code only in debug mode. Builds now generate a class called BuildConfig containing a DEBUGconstant that is automatically set according to your build type. You can check the (BuildConfig.DEBUG) constant in your code to run debug-only functions.
即:新增了一個特性,允許開發者只在Debug模式下運行部分代碼。Builds會生成一個叫做BuildConfig的類,該類包含一個名爲DEBUG的常量,其常量值會依據開發者的Build類型自動設定。如此,便可以利用BuildConfig.DEBUG來實現只在Debug模式下運行的代碼。
如果你的ADT已經更新到17及以上版本,可以嘗試在Eclipse中新建一個Android工程,你會發現和R.java同級目錄下多了一個叫做BuildConfig.java的類,其內容如下:
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">1</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">2</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">3</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">4</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">5</span> <span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">6</span> |
|
這樣只需要改動一行代碼就ok了,
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-family: inherit; font-style: inherit; font-variant: inherit; line-height: inherit; vertical-align: baseline; color: rgb(88, 110, 117) !important;">1</span> |
|
在上面提到,DEBUG會根據Build類型自動設定。那麼Build類型又從哪裏區分呢?很簡單,點開Eclipse的Project菜單便可見分曉,如下圖:
可見,Build類型分爲Build Project和Build Automatically,即手動和自動。
需要注意的是,如果直接通過Eclipse運行Project,則不論Build是手動還是自動,DEBUG均不會被設定爲false。這是爲什麼呢?這就牽涉到Android 簽名的問題,這裏只簡單提一下,不贅述:直接通過Eclipse運行Project,Eclipse會在工程Build完畢後在bin目錄下生成一個apk,這個apk的簽名是調試模式(debug mode),和發佈模式(release mode)簽名生成的apk略有不同。如此,該問題產生原因便浮出水面。
此時肯定會有人說,直接使用Android Tools–>Export Signed Application Package導出的release mode apk,其DEBUG就是false。這是不對的。在生成Release版時,需要區分Build的類型。如果選擇的是自動Build,那麼DEBUG仍然會被設定爲true。所以在生成Release版時,請按照下面這個步驟進行打包,BuildConfig.DEBUG會被修改爲false:
- Project -> Build Automatically,即取消Build Automatically
- Project -> Clean
- Project -> Build
- Android Tools -> Export Android application