兼容性最好的就是第一種夯尽，推薦使用冶忱，代碼量少尾菇，簡(jiǎn)單易用
<pre>
方法一:
String useragent = new WebView(this).getSettings().getUserAgentString();
方法二:
private static String getUserAgent() {
String userAgent = "";
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
try {
userAgent = WebSettings.getDefaultUserAgent(getInstance());
} catch (Exception e) {
userAgent = System.getProperty("http.agent");
}
} else {
userAgent = System.getProperty("http.agent");
}
StringBuffer sb = new StringBuffer();
for (int i = 0, length = userAgent.length(); i < length; i++) {
char c = userAgent.charAt(i);
if (c <= '\u001f' || c >= '\u007f') {
sb.append(String.format("\\u%04x", (int) c));
} else {
sb.append(c);
}
}
return sb.toString();
}
</pre>
