在我们的ScopePreviewWidget，我们可以利用audio PreviewWidget来播放我们的音乐。这对一些音乐的Scope来说，非常中要。在今天的练习中，我们来利用这个它来在我们的Scope中来试听我们的音乐。
首先我们来利用我们已经做好的Scope。我们可以下载我们先前做好的Scope:
git clone https://gitcafe.com/ubuntu/scopetemplates.git
在我们的query.cpp中，我们来添加如下的项：
query.cppvoid Query::pushResult(sc::SearchReplyProxy const& reply,const string renderer, int i) {stringstream ss;ss << i;string str = ss.str();auto cat = reply->register_category( "id" + str, "Template " + str ,"", sc::CategoryRenderer(renderer) );sc::CategorisedResult r(cat);r.set_uri( URI.toStdString() );r.set_art( images_[0].toStdString() );r["subtitle"] = "Subtitle " + str;r.set_title("Title " + str);r["summary"] = "Summary: " + str;r["fulldesc"] = "fulldesc: " + str;r["mascot"] = icons_[0].toStdString();r["emblem"] = icons_[1].toStdString();r["background"] = background_.toStdString();r["overlay-color"] = "#FF0000";QString likes = QString("%1 %2").arg(qstr(u8"\u261d "), "100");QString views = QString("%1 %2").arg(qstr(u8" \u261f "), "99");std::string both = qstr("%1 %2").arg(likes,views).toStdString();sc::VariantBuilder builder;builder.add_tuple({{"value", Variant(both)}});builder.add_tuple({{"value", Variant("")}});r["attributes"] = builder.end();r["musicSource"] = "魔音神据极品私货这锯子拉的耳膜都要碎了.mp3";if (!reply->push(r))return;}
上面的“musicSource”是我们新添加的项。我们必须指出的是，，“musicSource”不是我们标准的模版中的项，那么我们怎么在我们的Preview中利用这个项呢？preview.cpp
void Preview::run(sc::PreviewReplyProxy const& reply) {// Support three different column layoutssc::ColumnLayout layout1col(1), layout2col(2), layout3col(3);// We define 3 different layouts, that will be used depending on the// device. The shell (view) will decide which layout fits best.// If, for instance, we are executing in a tablet probably the view will use// 2 or more columns.// Column layout definitions are optional.// However, we recommend that scopes define layouts for the best visual appearance.// Single column layoutlayout1col.add_column( { "image", "header", "summary", "tracks" });// Two column layoutlayout2col.add_column( { "image" });layout2col.add_column( { "header", "summary", "tracks" });// Three cokumn layoutlayout3col.add_column( { "image" });layout3col.add_column( { "header", "summary", "tracks" });layout3col.add_column( { });// Register the layouts we just createdreply->register_layout( { layout1col, layout2col, layout3col });// Define the header sectionsc::PreviewWidget header("header", "header");// It has title and a subtitle propertiesheader.add_attribute_mapping("title", "title");header.add_attribute_mapping("subtitle", "subtitle");// Define the image sectionsc::PreviewWidget image("image", "image");// It has a single source property, mapped to the result's art propertyimage.add_attribute_mapping("source", "art");// Define the summary sectionsc::PreviewWidget description("summary", "text");// It has a text property, mapped to the result's description propertydescription.add_attribute_mapping("text", "description"); Result result = PreviewQueryBase::result();PreviewWidget listen("tracks", "audio");{VariantBuilder builder;builder.add_tuple({{"title", Variant("This is the song title")},{"source", Variant(result["musicSource"].get_string().c_str())}});listen.add_attribute_value("tracks", builder.end());}if ( result["musicSource"].get_string().length() != 0 ) {qDebug() << "it is not null";// Push each of the sectionsreply->push( { image, header, description, listen });} else {// Push each of the sectionsreply->push( { image, header, description });}}在这里，我们可以看到：
Result result = PreviewQueryBase::result();PreviewWidget listen("tracks", "audio");{VariantBuilder builder;builder.add_tuple({{"title", Variant("This is the song title")},{"source", Variant(result["musicSource"].get_string().c_str())}});listen.add_attribute_value("tracks", builder.end());}if ( result["musicSource"].get_string().length() != 0 ) {qDebug() << "it is not null";// Push each of the sectionsreply->push( { image, header, description, listen });} else {// Push each of the sectionsreply->push( { image, header, description });}我们可以通过“result()”的方法来得到result。我们同时创建了一个叫做listen的PreviewWidget。我们利用他来创建我们所需要的项。
运行我们的Scope:
生命太过短暂，今天放弃了明天不一定能得到
