Android Open Source - PatternAndroid Pull To Refresh Web View

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MIT License
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Java Source Code

/*******************************************************************************
 * Copyright 2011, 2012 Chris Banes./* w  w w .ja v a  2 s. c o  m*/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.handmark.pulltorefresh.library;

import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import android.util.AttributeSet;
import android.util.FloatMath;
import android.webkit.WebChromeClient;
import android.webkit.WebView;

public class PullToRefreshWebView extends PullToRefreshBase<WebView> {

  private static final OnRefreshListener<WebView> defaultOnRefreshListener = new OnRefreshListener<WebView>() {

    @Override
    public void onRefresh(PullToRefreshBase<WebView> refreshView) {
      refreshView.getRefreshableView().reload();
    }

  };

  private final WebChromeClient defaultWebChromeClient = new WebChromeClient() {

    @Override
    public void onProgressChanged(WebView view, int newProgress) {
      if (newProgress == 100) {
        onRefreshComplete();
      }
    }

  };

  public PullToRefreshWebView(Context context) {
    super(context);

    /**
     * Added so that by default, Pull-to-Refresh refreshes the page
     */
    setOnRefreshListener(defaultOnRefreshListener);
    mRefreshableView.setWebChromeClient(defaultWebChromeClient);
  }

  public PullToRefreshWebView(Context context, AttributeSet attrs) {
    super(context, attrs);

    /**
     * Added so that by default, Pull-to-Refresh refreshes the page
     */
    setOnRefreshListener(defaultOnRefreshListener);
    mRefreshableView.setWebChromeClient(defaultWebChromeClient);
  }

  public PullToRefreshWebView(Context context, Mode mode) {
    super(context, mode);

    /**
     * Added so that by default, Pull-to-Refresh refreshes the page
     */
    setOnRefreshListener(defaultOnRefreshListener);
    mRefreshableView.setWebChromeClient(defaultWebChromeClient);
  }

  public PullToRefreshWebView(Context context, Mode mode, AnimationStyle style) {
    super(context, mode, style);

    /**
     * Added so that by default, Pull-to-Refresh refreshes the page
     */
    setOnRefreshListener(defaultOnRefreshListener);
    mRefreshableView.setWebChromeClient(defaultWebChromeClient);
  }

  @Override
  public final Orientation getPullToRefreshScrollDirection() {
    return Orientation.VERTICAL;
  }

  @Override
  protected WebView createRefreshableView(Context context, AttributeSet attrs) {
    WebView webView;
    if (VERSION.SDK_INT >= VERSION_CODES.GINGERBREAD) {
      webView = new InternalWebViewSDK9(context, attrs);
    } else {
      webView = new WebView(context, attrs);
    }

    webView.setId(R.id.webview);
    return webView;
  }

  @Override
  protected boolean isReadyForPullStart() {
    return mRefreshableView.getScrollY() == 0;
  }

  @Override
  protected boolean isReadyForPullEnd() {
    float exactContentHeight = FloatMath.floor(mRefreshableView.getContentHeight() * mRefreshableView.getScale());
    return mRefreshableView.getScrollY() >= (exactContentHeight - mRefreshableView.getHeight());
  }

  @Override
  protected void onPtrRestoreInstanceState(Bundle savedInstanceState) {
    super.onPtrRestoreInstanceState(savedInstanceState);
    mRefreshableView.restoreState(savedInstanceState);
  }

  @Override
  protected void onPtrSaveInstanceState(Bundle saveState) {
    super.onPtrSaveInstanceState(saveState);
    mRefreshableView.saveState(saveState);
  }

  @TargetApi(9)
  final class InternalWebViewSDK9 extends WebView {

    // WebView doesn't always scroll back to it's edge so we add some
    // fuzziness
    static final int OVERSCROLL_FUZZY_THRESHOLD = 2;

    // WebView seems quite reluctant to overscroll so we use the scale
    // factor to scale it's value
    static final float OVERSCROLL_SCALE_FACTOR = 1.5f;

    public InternalWebViewSDK9(Context context, AttributeSet attrs) {
      super(context, attrs);
    }

    @Override
    protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX,
        int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {

      final boolean returnValue = super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX,
          scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);

      // Does all of the hard work...
      OverscrollHelper.overScrollBy(PullToRefreshWebView.this, deltaX, scrollX, deltaY, scrollY,
          getScrollRange(), OVERSCROLL_FUZZY_THRESHOLD, OVERSCROLL_SCALE_FACTOR, isTouchEvent);

      return returnValue;
    }

    private int getScrollRange() {
      return (int) Math.max(0, FloatMath.floor(mRefreshableView.getContentHeight() * mRefreshableView.getScale())
          - (getHeight() - getPaddingBottom() - getPaddingTop()));
    }
  }
}
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