Sebastian Benz
本指南介绍了如何衡量 Chrome 自定义标签页的互动信号。如果您的应用会定期向用户显示指向网络内容的链接（例如在新闻 Feed 中），那么了解哪些链接对用户有价值，哪些链接没有价值可能非常重要。在自定义标签页中，您可以通过导航次数、滚动方向更改次数和滚动深度来衡量会话专用用户互动情况。如需查看互动信号的实际运作方式，请参阅 GitHub 上的自定义标签页演示应用。
Custom Tabs 提供了两种不同的回调来衡量用户互动度：
CustomTabsCallback，用于跟踪基本导航事件，例如"NAVIGATION_STARTED"或"NAVIGATION_FINISHED"。EngagementSignalsCallback，用于跟踪特定网页的用户互动情况，例如滚动方向或滚动百分比。
这两种方式都需要有效的 CustomTabsServiceConnection。如需详细了解如何连接到 CustomTabsService，请参阅之前的 CustomTabsService 指南。
如需衡量用户互动度，请先创建 CustomTabsCallback 和 EngagementSignalsCallback 实例。CustomTabsCallback 会收到一个 navigationEvent 常量，用于描述发生了哪种导航：
private CustomTabsCallback mCustomTabsCallback = new CustomTabsCallback() {
@Override
public void onNavigationEvent(int navigationEvent, @Nullable Bundle extras) {
String event;
switch (navigationEvent) {
case CustomTabsCallback.NAVIGATION_ABORTED:
event = "NAVIGATION_ABORTED";
break;
case CustomTabsCallback.NAVIGATION_FAILED:
event = "NAVIGATION_FAILED";
break;
case CustomTabsCallback.NAVIGATION_FINISHED:
event = "NAVIGATION_FINISHED";
break;
case CustomTabsCallback.NAVIGATION_STARTED:
event = "NAVIGATION_STARTED";
break;
case CustomTabsCallback.TAB_SHOWN:
event = "TAB_SHOWN";
break;
case CustomTabsCallback.TAB_HIDDEN:
event = "TAB_HIDDEN";
break;
default:
event = String.valueOf(navigationEvent);
}
Log.d(TAG, "onNavigationEvent (navigationEvent=" + event + ')');
mTextNavigation.setText("onNavigationEvent " + event);
}
};
EngagementSignalsCallback 支持三种不同的回调：
onVerticalScrollEvent()- 每当用户更改滚动方向时都会调用，其中
isDirectionUp（第一个参数）表示方向。
onGreatestScrollPercentageIncreased：当用户到达页面底部时，自定义标签页会以 5% 的间隔（最高 100%）发出滚动深度信号。只有在用户停止滚动后，系统才会调用回调。每次重新导航时，此值都会重置为 0%。onSessionEnded：自定义标签页在停止发送互动信号时触发此事件（例如，在用户关闭自定义标签页后）。如果用户以任何方式（滚动、点击按钮等）与网页互动，didUserInteract将为 true。
private EngagementSignalsCallback mEngagementSignalsCallback = new EngagementSignalsCallback() {
@Override
public void onVerticalScrollEvent(boolean isDirectionUp, @NonNull Bundle extras) {
Log.d(TAG, "onVerticalScrollEvent (isDirectionUp=" + isDirectionUp + ')');
mTextVerticalScroll.setText("vertical scroll " + (isDirectionUp ? "UP️" : "DOWN"));
}
@Override
public void onGreatestScrollPercentageIncreased(int scrollPercentage, @NonNull Bundle extras) {
Log.d(TAG, "scroll percentage: " + scrollPercentage + "%");
mTextGreatestPercentage.setText("scroll percentage: " + scrollPercentage + "%");
}
@Override
public void onSessionEnded(boolean didUserInteract, @NonNull Bundle extras) {
Log.d(TAG, "onSessionEnded (didUserInteract=" + didUserInteract + ')');
mTextSessionEnd.setText(didUserInteract ? "session ended with user interaction" : "session ended without user interaction");
}
};
CustomTabsCallback 和 EngagementSignalsCallback 都需要有效的自定义标签页服务连接。服务连接后，您可以通过调用 CustomTabsClient.newSession() 并传递 CustomTabsCallback 来创建新的 CustomTabsSession。
之后，您应调用 isEngagementSignalsApiAvailable() 以检查当前浏览器是否支持互动信号。如果受支持，您可以通过 CustomTabsSession.setEngagementSignalsCallback() 注册 EngagementSignalsCallback。
private CustomTabsClient mCustomTabsClient;
private CustomTabsSession mCustomTabsSession;
private final CustomTabsServiceConnection mServiceConnectionCallback = new CustomTabsServiceConnection() {
@Override
public void onCustomTabsServiceConnected(@NonNull ComponentName name, @NonNull CustomTabsClient client) {
mCustomTabsClient = client;
mCustomTabsSession = mCustomTabsClient.newSession(mCustomTabsCallback);
try {
boolean engagementSignalsApiAvailable = mCustomTabsSession.isEngagementSignalsApiAvailable(Bundle.EMPTY);
if (!engagementSignalsApiAvailable) {
Log.d(TAG, "CustomTab Engagement signals not available, make sure to use the " +
"latest Chrome version and enable via chrome://flags/#cct-real-time-engagement-signals");
return;
}
mCustomTabsSession.setEngagementSignalsCallback(mEngagementSignalsCallback, Bundle.EMPTY);
} catch (RemoteException e) {
Log.w(TAG, "The Service died while responding to the request.", e);
} catch (UnsupportedOperationException e) {
Log.w(TAG, "Engagement Signals API isn't supported by the browser.", e);
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
mCustomTabsClient = null;
mConnection = null;
mCustomTabsSession = null;
}
};
剩下唯一要做的就是绑定 CustomTabsService：
@Override
protected void onStart() {
super.onStart();
bindCustomTabsService();
}
private void bindCustomTabsService() {
String packageName = CustomTabsHelper.getPackageNameToUse(this);
if (packageName == null) return;
CustomTabsClient.bindCustomTabsService(this, packageName, mConnection);
}