Android 通过代码设置 webview 代理显示成功，但是不生效，有人遇到这种问题吗

private static boolean setProxyICS(Context context, String host, int port) {
try {
Class jwcjb = Class.forName("android.webkit.JWebCoreJavaBridge");
Class params[] = new Class[1];
params[0] = Class.forName("android.net.ProxyProperties");
Method updateProxyInstance = jwcjb.getDeclaredMethod("updateProxy", params);

Class wv = Class.forName("android.webkit.WebView");
Field mWebViewCoreField = wv.getDeclaredField("mWebViewCore");
Object mWebViewCoreFieldInstance = getFieldValueSafely(mWebViewCoreField, context);

Class wvc = Class.forName("android.webkit.WebViewCore");
Field mBrowserFrameField = wvc.getDeclaredField("mBrowserFrame");
Object mBrowserFrame = getFieldValueSafely(mBrowserFrameField, mWebViewCoreFieldInstance);

Class bf = Class.forName("android.webkit.BrowserFrame");
Field sJavaBridgeField = bf.getDeclaredField("sJavaBridge");
Object sJavaBridge = getFieldValueSafely(sJavaBridgeField, mBrowserFrame);

Class ppclass = Class.forName("android.net.ProxyProperties");
Class pparams[] = new Class[3];
pparams[0] = String.class;
pparams[1] = int.class;
pparams[2] = String.class;
Constructor ppcont = ppclass.getConstructor(pparams);
updateProxyInstance.invoke(sJavaBridge, ppcont.newInstance(host, port, null));
return true;
} catch (Exception ex) {
return false;
}
}