SharedPreferences判断程序是否第一次安装

# To enable ProGuard in your project, edit project.properties # to define the proguard.config property as described in that file. # # Add project specific ProGuard rules here. # By default, the flags in this file are appended to flags specified # in ${sdk.dir}/tools/proguard/proguard-android.txt # You can edit the include path and order by changing the ProGuard # include property in project.properties. # # For more details, see # http://developer.android.com/guide/developing/tools/proguard.html # Add any project specific keep options here: # If your project uses WebView with JS, uncomment the following # and specify the fully qualified class name to the JavaScript interface # class: #-keepclassmembers class fqcn.of.javascript.interface.for.webview { # public *; #}