Android:获取WebView的滚动位置 [英] Android: Get the scroll position of a WebView

问题描述

我是Android的新手.

I'm new to Android.

我只想简单地知道用户在页面上的滚动位置.当网页上的某个点出现在屏幕底部时，我想触发一个事件.但是此代码会导致异常.我知道WebView从View继承了 getScrollY().我执行不正确吗?

I would like to simply know where on a page the user has scrolled. When a certain point on the web page appears at the bottom of the screen, I want to trigger an event. But this code causes an exception. I know that WebView inherits getScrollY() from View. Am I not implementing it correctly?

谢谢.

public class Scroll extends Activity {

    public WebView webview;
    public float yPos;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        WebView webview = new WebView(this);
        setContentView(webview);
        webview.loadUrl("file:///android_asset/Scroll.html");
    }


    public boolean onTouchEvent(final MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_MOVE) {
            yPos = webview.getScrollY();
            Log.v("Scroll", "yPos = " + yPos); 
        }
        return false;
    }
}

推荐答案

例外是?
这是有关我的一个应用程序的WebView屏幕高度的注释:

And the exception is?
Here is a note on WebView screen heights from one of my apps:

// current position (top) = getScrollY();  
// max position = getContentHeight();  
// screen height = getHeight();

这篇关于Android:获取WebView的滚动位置的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！