SharedPreferences sharedPreferences = this.getSharedPreferences("share", MODE_PRIVATE); 
boolean isFirstRun = sharedPreferences.getBoolean("isFirstRun", true); 
Editor editor = sharedPreferences.edit(); 
if (isFirstRun) 
{ 
Log.d("debug", "第一次运行"); 
editor.putBoolean("isFirstRun", false); 
editor.commit(); 
} else 
{ 
Log.d("debug", "不是第一次运行"); 
}

SharedPreferences sharedPreferences = this.getSharedPreferences("share", MODE_PRIVATE);
//此处表示该应用程序专用
boolean isFirstRun = sharedPreferences.getBoolean("isFirstRun", true);
//此处表示如果key "isFirstRun"对应的value没有值则默认为true，
//否则就把对应的value取出赋值给变量isFirstRun
Editor editor = sharedPreferences.edit();
editor.putBoolean("isFirstRun", false);
//此处表示putBoolean(key, value)，
//将value写入对应的key，而且是一一对应的
editor.commit();
//将isFirstRun写入editor中保存