Best IT Recipes

How to make a scroll listener for WebView in Android

How to implement a scroll listener for WebView in Android

I tried this but did not call my Log.i when scrolling through the web view.

 package com.example.webview.full.width; import android.content.Context; import android.util.AttributeSet; import android.util.Log; import android.webkit.WebView; import android.widget.AbsListView; import android.widget.AbsListView.OnScrollListener; public class scorllableWebview extends WebView implements OnScrollListener { Context ctx; AttributeSet atrs; public scorllableWebview(Context context) { super(context); ctx = context; } public scorllableWebview(Context context, AttributeSet atters){ super(context, atters); ctx = context; atrs = atters; } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { Log.i("onScroll", "Called"); } @Override public void onScrollStateChanged(AbsListView view, int scrollState) { Log.i("onScrollStateChanged", "Called"); } }

Here is my MainActivity.java

 package com.example.webview.full.width; import android.app.Activity; import android.app.ProgressDialog; import android.os.Bundle; import android.view.Menu; import android.webkit.WebView; import android.webkit.WebViewClient; import android.widget.Toast; public class MainActivity extends Activity { ProgressDialog progressDialog; scorllableWebview wv; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); wv = (scorllableWebview) findViewById(R.id.scorllableWebview); wv.getSettings().setJavaScriptEnabled(true); wv.getSettings().setBuiltInZoomControls(true); wv.getSettings().supportZoom(); progressDialog = ProgressDialog.show(MainActivity.this, "Loading Book...!", "Please Wait"); progressDialog.setCancelable(true); String htnlString = "<!DOCTYPE html><html><body style = \"text-align:center\"><script type=\"text/javascript\">for(a=1;a<=10;a++)document.write('<img style=\"border-style:dotted;border-width:10px;border-color:black;\"src=\"http://myURL.com/books_snaps/EN567/'+a+'.jpg\" alt=\"Page Not Found\"/>');</script></body></html>"; // width=\"100%\" wv.setWebViewClient(new WebViewClient() { @Override public void onPageFinished(WebView view, String url) { progressDialog.dismiss(); Toast.makeText(MainActivity.this, "Completed", Toast.LENGTH_SHORT).show(); wv.pageUp(true); super.onPageFinished(view, url); } }); wv.loadDataWithBaseURL(null, htnlString, "text/html", "UTF-8", null); } }

and here is my xml file.

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" > <com.example.webview.full.width.scorllableWebview xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/scorllableWebview" android:layout_width="match_parent" android:layout_height="match_parent" /> </RelativeLayout>
+42
android webview scrollview custom-controls
Feb 07 '13 at 13:40
source share
3 answers

Something like:

 public class ObservableWebView extends WebView { private OnScrollChangedCallback mOnScrollChangedCallback; public ObservableWebView(final Context context) { super(context); } public ObservableWebView(final Context context, final AttributeSet attrs) { super(context, attrs); } public ObservableWebView(final Context context, final AttributeSet attrs, final int defStyle) { super(context, attrs, defStyle); } @Override protected void onScrollChanged(final int l, final int t, final int oldl, final int oldt) { super.onScrollChanged(l, t, oldl, oldt); if(mOnScrollChangedCallback != null) mOnScrollChangedCallback.onScroll(l, t, oldl, oldt); } public OnScrollChangedCallback getOnScrollChangedCallback() { return mOnScrollChangedCallback; } public void setOnScrollChangedCallback(final OnScrollChangedCallback onScrollChangedCallback) { mOnScrollChangedCallback = onScrollChangedCallback; } /** * Impliment in the activity/fragment/view that you want to listen to the webview */ public static interface OnScrollChangedCallback { public void onScroll(int l, int t, int oldl, int oldt); } }

It should work, this is not tested, but it works for almost any other view in Android.

You would implement as:

 wv = (ObservableWebView) findViewById(R.id.scorllableWebview); wv.setOnScrollChangedCallback(new OnScrollChangedCallback(){ public void onScroll(int l, int t, int oldl, int oldt){ if(t> oldt){ //Do stuff System.out.println("Swipe UP"); //Do stuff } else if(t< oldt){ System.out.println("Swipe Down"); } Log.d(TAG,"We Scrolled etc..."); } });
+86
Feb 07 '13 at 14:16
source share

Starting with API 23 you will no longer need to do this, you can just use the new OnScrollChangeListener for all kinds, including the WebView . But since you still need to support older versions, you can still use the sentence from @ Chris.Jenkins. I made some adjustments to the proposed class in a "more compatible" with the new OnScrollChangeListener interface:

 public class ObservableWebView extends WebView { private OnScrollChangeListener onScrollChangeListener; public ObservableWebView(Context context) { super(context); } public ObservableWebView(Context context, AttributeSet attrs) { super(context, attrs); } public ObservableWebView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @Override protected void onScrollChanged(int l, int t, int oldl, int oldt) { super.onScrollChanged(l, t, oldl, oldt); if (onScrollChangeListener != null) { onScrollChangeListener.onScrollChange(this, l, t, oldl, oldt); } } public void setOnScrollChangeListener(OnScrollChangeListener onScrollChangeListener) { this.onScrollChangeListener = onScrollChangeListener; } public OnScrollChangeListener getOnScrollChangeListener() { return onScrollChangeListener; } public interface OnScrollChangeListener { /** * Called when the scroll position of a view changes. * * @param v The view whose scroll position has changed. * @param scrollX Current horizontal scroll origin. * @param scrollY Current vertical scroll origin. * @param oldScrollX Previous horizontal scroll origin. * @param oldScrollY Previous vertical scroll origin. */ void onScrollChange(WebView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY); } }
+21
Dec 05 '15 at 20:20
source share

Try this (for the whole view, what you want): create a GestureDetector, then TouchListener and set to view who scrolls

 OnCreate private GestureDetector gestureDetector; gestureDetector = new GestureDetector(this, new GestureDetector.SimpleOnGestureListener() { @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { if (velocityY < 0) { collapse(frToolBar); } else if (velocityY > 0) { if (frToolBar.getVisibility()==View.GONE) expand(frToolBar); } return super.onFling(e1, e2, velocityX, velocityY); } @Override public boolean onDown(MotionEvent e) { return super.onDown(e); } }); webView.setOnTouchListener((view, motionEvent) -> gestureDetector.onTouchEvent(motionEvent)); Two method - public static void expand(final View v) { v.measure(WindowManager.LayoutParams.MATCH_PARENT, indowManager.LayoutParams.WRAP_CONTENT); // final int targetHeight = v.getMeasuredHeight(); final int targetHeight = v.getHeight(); v.getLayoutParams().height = 1; v.setVisibility(View.VISIBLE); Animation a = new Animation() { @Override protected void applyTransformation(float interpolatedTime, Transformation t) { v.getLayoutParams().height = interpolatedTime == 1 ? WindowManager.LayoutParams.WRAP_CONTENT : (int) (targetHeight * interpolatedTime); v.requestLayout(); } @Override public boolean willChangeBounds() { return true; } }; a.setDuration(300); v.startAnimation(a); } public static void collapse(final View v) { final int initialHeight = v.getMeasuredHeight(); Animation a = new Animation() { @Override protected void applyTransformation(float interpolatedTime, Transformation t) { if (interpolatedTime == 1) { v.setVisibility(View.GONE); } else { v.getLayoutParams().height = initialHeight - (int) (initialHeight * interpolatedTime); v.requestLayout(); } } @Override public boolean willChangeBounds() { return true; } }; a.setDuration(300); v.startAnimation(a); }
0
Jun 06 '19 at 8:22
source share


More articles:


All Articles