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My Android app uses a WebView to display a bunch of HTML code that I generate 'on the fly'. The HTML code is loaded using the following code:
StringBuilder builder = new StringBuilder();
// HTML
builder.append("<html><head><link rel=\"stylesheet\" href=\"file:///android_asset/style.css\" type=\"text/css\">");
builder.append("</link></head><body>");
builder.append(getThreadBody());
builder.append("</body></html>");
webview.loadDataWithBaseURL("file:///android_asset/", builder.toString(), "text/html", "utf-8", null);
This all works really nice. Note that I'm not loading an actual HTML file, I'm merely creating a string that represents some (hopefully valid) HTML and load it in the WebView.
Anyway, the HTML I generate (the part in the 'getThreadBody' method) contains named anchors, for example like this;
<div>
<a name="949823">Anchor 1</a>
<div>All kinds of stuff</div>
<a name="895984">Anchor 2</a>
<div>...</div>
</div>
Now in some cases I want the WebView to navigate to one of those anchors as soon as I load the HTML. As far as I understand the WebView supports navigating (scrolling in this case) to named anchors, but the catch is that nobody is clicking any hyperlinks to those anchors, I want the WebView to scroll when it is loaded (it is no problem if there is a short delay between loading the HTML and scrolling, my point is that it should not require user interaction).
I believe the behavior can be achieved by using the WebView's loadUrl method and supplying a URL with the anchor in place, eg
webview.loadUrl("file:///android_asset/page.html#895984", ...)
However, since I am not saving the HTML to any file I cannot use this method... Of course saving the HTML to a temporary file may be a solution but I'd like to keep that as a last resort, there must be a simpler way?
How can I achieve this? Thanks!
Resolved Here's the code that works. I found a short delay was required to let the page load before executing the javascript otherwise it was kind of 50/50 whether it worked or not...
StringBuilder builder = new StringBuilder();
// HTML
builder.append("<html><head><link rel=\"stylesheet\" href=\"file:///android_asset/style.css\" type=\"text/css\">");
builder.append("</link>");
builder.append("<script>");
builder.append("function scrollAnchor(id) {");
builder.append("window.location.hash = id;}");
builder.append("</script>");
builder.append("</head><body>");
builder.append(getThreadBody());
builder.append("</body></html>");
webContents.loadDataWithBaseURL("file:///android_asset/", builder.toString(), "text/html", "utf-8", null);
Timer timer = new Timer();
timer.schedule(new TimerTask() {
@Override
public void run() {
String id = "895884";
webContents.loadUrl("javascript:scrollAnchor(" + id + ");");
}
}
}, 250);
954
How about control it by JavaScript? I didn't try it but maybe this is a clue.
builder.append(getThreadBody());
builder.append("<script>window.location.hash="949823";</script>");
builder.append("</body></html>");
Remember enable javascript for WebView.
----Additional Answer----
I saw that you use TimerTask to load the javascript, That works but I think there is another better way. WebView have a callback named onPageFinished and it will be trigger when WebView finish loading webpage. You could inject your JS there.
webContents.setWebViewClient(new WebViewClient(){
@Override
public void onPageFinished(WebView view, String url) {
String id = "895884";
webContents.loadUrl("javascript:scrollAnchor(" + id + ");");
}
});
Hope this is useful!
76
First of all, you don't need to use javascript. If you loaded content with
webContents.loadDataWithBaseURL("some://dummy/url",...);
you can simply scroll to anchor with
webContents.loadUrl("some://dummy/url#anchor");
Secondly, doing that on onPageFinished without additional control results in never ending loop! When loadUrl finishes onPageFinished get's called again and again.
39
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