不管你技术如何，只要背点这个，能忽悠倒一片。。
1、WebView JS漏洞 ，Android4.2之前 ，解决办法，不用addJavascriptInterface，webchrome的onJsPrompt Android4.2之后 @JavascriptInterface
2、Service OnstartCommand Android 2.0 之后 取代 Onstart // This is the old onStart method that will be called on the pre-2.0 // platform. On 2.0 or later we override onStartCommand() so this // method will not be called. OnstartCommand 的 返回值也可以背住。
3、相册 4.4 DocumentsContract 通过添加权限 可以实现shortcut。打印功能，NFC 不用sim卡
4、5.0 锁屏 互动 service 需要一个 explicit Intent 不要给service声明intentfilter； 自定义权限不再支持。Android 5的锁屏小工具不支持；继续支持在主屏幕小部件
5、6.0 蓝牙wifi The WifiInfo.getMacAddress() and the BluetoothAdapter.getAddress() methods now return a constant value of 02:00:00:00:00:00 To access the hardware identifiers of nearby external devices via Bluetooth and Wi-Fi scans, your app must now have the ACCESS_FINE_LOCATION or ACCESS_COARSE_LOCATION permission
通知 This release removes the Notification.setLatestEventInfo() method. Use the Notification.Builder class instead to construct notifications. To update a notification repeatedly, reuse the Notification.Builder instance. Call the build() method to get updated Notification instances. The adb shell dumpsys notification command no longer prints out your notification text. Use the adb shell dumpsys notification --noredact command instead to print out the text in a notification object. Browser Bookmark Changes
6.0sdk 取消httpclient相关类。