[Android]Update readme. (#355)

Author: xgfd3

Android/APIExample/README.md

@@ -23,7 +23,7 @@ To build and run the sample application, get an App Id:
 3. Save the **App Id** from the Dashboard for later use.
 4. Save the **App Certificate** from the Dashboard for later use.
 
-5. Open `Android/APIExample` and edit the `app/src/main/res/values/string-config.xml` file. Update `YOUR APP ID` with your App Id, update `YOUR APP CERTIFICATE` with the main app certificate from dashboard. Note you can leave the certificate variable `null` if your project has not turned on security token.
+5. Open `Android/APIExample` and edit the `app/src/main/res/values/string-configs.xml` file. Update `YOUR APP ID` with your App Id, update `YOUR APP CERTIFICATE` with the main app certificate from dashboard. Note you can leave the certificate variable `null` if your project has not turned on security token.
 
     ```
     // Agora APP ID.

Android/APIExample/README.zh.md

@@ -23,7 +23,7 @@
 3. 复制后台的 **App Id** 并备注，稍后启动应用时会用到它
 4. 复制后台的 **App 证书** 并备注，稍后启动应用时会用到它
 
-5. 打开 `Android/APIExample` 并编辑 `app/src/main/res/values/string-config.xml`，将你的 AppID 、App主证书 分别替换到 `Your App Id` 和 `YOUR APP CERTIFICATE`
+5. 打开 `Android/APIExample` 并编辑 `app/src/main/res/values/string-configs.xml`，将你的 AppID 、App主证书 分别替换到 `Your App Id` 和 `YOUR APP CERTIFICATE`
 
     ```
     // 声网APP ID。