Android Open Source - Common-Library Direction Scroll View

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License

The source code is released under:

Apache License

Java Source Code

package com.morgan.library.widget;
/* w w w.  j a v a  2  s  . c om*/
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ScrollView;

/**
 * ????????????????????{@link #mOnDirectionChangeListener}?????ScrollView
 * 
 * @author Morgan.Ji
 * 
 */
public class DirectionScrollView extends ScrollView {

  public static final int DIRECTION_NONE = 0;
  public static final int DIRECTION_UP = 1;
  public static final int DIRECTION_DOWN = 2;
  private OnScrollDirectionChangeListener mOnDirectionChangeListener;
  private boolean mRecord = false;

  public DirectionScrollView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
  }

  public DirectionScrollView(Context context) {
    super(context);
  }

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

  @Override
  protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    super.onScrollChanged(l, t, oldl, oldt);
    if (null != mOnDirectionChangeListener && mRecord) {
      if (t > oldt) {
        mOnDirectionChangeListener.onDirectionChange(DIRECTION_DOWN);
      } else if (t < oldt) {
        mOnDirectionChangeListener.onDirectionChange(DIRECTION_UP);
      } else {
        mOnDirectionChangeListener.onDirectionChange(DIRECTION_NONE);
      }
    }
  }

  @Override
  public boolean onInterceptTouchEvent(MotionEvent ev) {
    switch (ev.getAction()) {
    case MotionEvent.ACTION_DOWN:
      mRecord = true;
      break;
    case MotionEvent.ACTION_UP:
    case MotionEvent.ACTION_CANCEL:
      mRecord = false;
      break;
    default:
      break;
    }
    return super.onInterceptTouchEvent(ev);
  }

  public OnScrollDirectionChangeListener getOnScrollDirectionChangeListener() {
    return mOnDirectionChangeListener;
  }

  public void setOnScrollDirectionChangeListener(
      OnScrollDirectionChangeListener mScrollDirectionChangeListener) {
    this.mOnDirectionChangeListener = mScrollDirectionChangeListener;
  }

  public boolean isRecord() {
    return mRecord;
  }

  public void setRecord(boolean mRecord) {
    this.mRecord = mRecord;
  }

  public interface OnScrollDirectionChangeListener {
    public void onDirectionChange(int direction);
  }
}

Java Source Code List

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