参考谷歌浏览器设置页面下载为例：1、前端js lazy_load.js
需要在chrome\browser\resources\settings\BUILD.gn里面加进来if (optimize_webui) {build_manifest = "build_manifest.json"optimize_webui("build") {host = "settings"input = rebase_path("$target_gen_dir/tsc", root_build_dir)js_module_in_files = ["settings.js","lazy_load.js", #追加自己的js即可]js_out_files = ["settings.rollup.js","lazy_load.rollup.js","shared.rollup.js",]out_manifest = "$target_gen_dir/$build_manifest"deps = [":build_ts","//ui/webui/resources:preprocess",]if (!is_chromeos_ash) {deps += [ "//ui/webui/resources/cr_components/customize_themes:build_ts" ]}if (use_nss_certs) {deps +=[ "//ui/webui/resources/cr_components/certificate_manager:build_ts" ]}excludes = ["chrome://resources/js/cr.m.js","chrome://resources/mojo/mojo/public/js/bindings.js","chrome://resources/mojo/skia/public/mojom/skcolor.mojom-webui.js",]}
}if (optimize_webui) {deps = [":build","privacy_sandbox:build_grdp",]manifest_files = [ "$target_gen_dir/$build_manifest" ]resource_path_rewrites = ["settings.rollup.js|settings.js","lazy_load.rollup.js|lazy_load.js",]grdp_files = [ "$target_gen_dir/privacy_sandbox/resources.grdp" ]} else {deps = [ ":build_ts" ]manifest_files = [ "$target_gen_dir/tsconfig.manifest" ]}方法:selectDownloadLocation() {chrome.send("selectDownloadLocation")}================================================================2、chrome\browser\ui\webui\settings\settings_ui.cc
在SettingsUI::SettingsUI(content::WebUI* web_ui) 注册下
{AddSettingsPageUIHandler(std::make_unique<DownloadsHandler>(profile));
}3、自定义页面按照这个复制即可
chrome\browser\ui\webui\settings\downloads_handler.cc
chrome\browser\ui\webui\settings\downloads_handler.hnamespace settings {// Chrome "Downloads" settings page UI handler.
class DownloadsHandler : public SettingsPageUIHandler,public ui::SelectFileDialog::Listener {public:explicit DownloadsHandler(Profile* profile);DownloadsHandler(const DownloadsHandler&) = delete;DownloadsHandler& operator=(const DownloadsHandler&) = delete;~DownloadsHandler() override;// SettingsPageUIHandler implementation.void RegisterMessages() override; //需要重载这个注册回调函数void OnJavascriptAllowed() override;void OnJavascriptDisallowed() override;
.............};}4、在DownloadsHandler 里面添加webui注册函数
void DownloadsHandler::RegisterMessages() {web_ui()->RegisterMessageCallback("initializeDownloads",base::BindRepeating(&DownloadsHandler::HandleInitialize,base::Unretained(this)));web_ui()->RegisterMessageCallback("resetAutoOpenFileTypes",base::BindRepeating(&DownloadsHandler::HandleResetAutoOpenFileTypes,base::Unretained(this)));web_ui()->RegisterMessageCallback("selectDownloadLocation",base::BindRepeating(&DownloadsHandler::HandleSelectDownloadLocation,base::Unretained(this)));
#if BUILDFLAG(IS_CHROMEOS_ASH)web_ui()->RegisterMessageCallback("getDownloadLocationText",base::BindRepeating(&DownloadsHandler::HandleGetDownloadLocationText,base::Unretained(this)));
#endifweb_ui()->RegisterMessageCallback("setDownloadsConnectionAccountLink",base::BindRepeating(&DownloadsHandler::HandleSetDownloadsConnectionAccountLink,base::Unretained(this)));
}5、对应实现
void DownloadsHandler::HandleSelectDownloadLocation(const base::Value::List& args) {// Early return if the select folder dialog is already active.if (select_folder_dialog_)return;PrefService* pref_service = profile_->GetPrefs();select_folder_dialog_ = ui::SelectFileDialog::Create(this,std::make_unique<ChromeSelectFilePolicy>(web_ui()->GetWebContents()));ui::SelectFileDialog::FileTypeInfo info;info.allowed_paths = ui::SelectFileDialog::FileTypeInfo::NATIVE_PATH;select_folder_dialog_->SelectFile(ui::SelectFileDialog::SELECT_FOLDER,l10n_util::GetStringUTF16(IDS_SETTINGS_DOWNLOAD_LOCATION),pref_service->GetFilePath(prefs::kDownloadDefaultDirectory), &info, 0,base::FilePath::StringType(),web_ui()->GetWebContents()->GetTopLevelNativeWindow(), NULL);
}6、webui调用c++代码执行结果效果如图：
