Android Open Source - Mapyst Sliding Scroll View

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright (C) 2013 Mapyst/* w  ww  .j  a va 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.mapyst.android.ui;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Handler;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;

public class SlidingScrollView extends HorizontalScrollView implements
    OnTouchListener {

  private int activeView = 1;

    private LinearLayout linearLayout;

  private boolean isRefreshing = false;

  private ActiveViewChangeListener onActiveViewChangeListener;

  public void setOnActiveViewChangeListener(ActiveViewChangeListener onActiveViewChangeListener) {
    this.onActiveViewChangeListener = onActiveViewChangeListener;
  }

  public interface ActiveViewChangeListener {
    public void activeSet(int active, View activeV);
  }

  public SlidingScrollView(Context context) {
    super(context);
    init(context);
  }

  public SlidingScrollView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init(context);

  }

  private boolean locked = true;

  public void lock() {
    this.locked = true;
    this.invalidate();
  }

  public void unlock() {
    this.locked = false;
    this.invalidate();
  }

  public boolean isLocked() {
    return locked;
  }

  @Override
  public boolean onTouchEvent(MotionEvent e) {
    if (locked)
      return true;
    else
      return super.onTouchEvent(e);
  }

  public void init(Context context) {
    this.setFadingEdgeLength(0);
    this.setHorizontalScrollBarEnabled(false);
    this.setWillNotDraw(false);
    this.setOnTouchListener(this);

    linearLayout = new LinearLayout(context);
    linearLayout.setOrientation(LinearLayout.HORIZONTAL);
    super.addView(linearLayout);
    refreshActiveView();

  }

  @Override
  public void addView(View v) {
    linearLayout.addView(v, linearLayout.getChildCount());
    viewAdded();
  }

  @Override
  public void addView(View child, ViewGroup.LayoutParams params) {
    linearLayout.addView(child, linearLayout.getChildCount(), params);
    viewAdded();
  }

  private void viewAdded() {
    ensureAllChildrenLargeEnough();
    refreshActiveView();
  }

  @Override
  public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    refreshActiveView();
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  }

  @Override
  public void onDraw(Canvas canvas) {
    refreshActiveView();
    super.onDraw(canvas);
  }

  public void setActiveView(View child) {
    setActiveView(linearLayout.indexOfChild(child));
  }

  public void setActiveView(int i) {
    activeView = i;
    refreshActiveView();
    if (onActiveViewChangeListener != null)
      onActiveViewChangeListener.activeSet(activeView, linearLayout.getChildAt(activeView));
  }

  public int getIndex(View view) {
    return linearLayout.indexOfChild(view);
  }

  public int getActiveView() {
    return activeView;
  }

  public void ensureAllChildrenLargeEnough() {
    for (int i = 0; i < linearLayout.getChildCount(); i++) {
      View child = linearLayout.getChildAt(i);
      ensureLargeEnough(child);
    }
  }

  public void ensureActiveLargeEnough() {
    View child = linearLayout.getChildAt(activeView);
    ensureLargeEnough(child);
  }

  public void ensureLargeEnough(View child) {
        int mainView = 1;
        if (linearLayout.indexOfChild(child) == mainView
        && !(child.getLayoutParams() != null && child.getLayoutParams().width == this.getWidth())) {
      LinearLayout.LayoutParams layout = (LinearLayout.LayoutParams) child.getLayoutParams();
      if (layout == null)
        layout = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.FILL_PARENT);
      layout.width = this.getWidth();
      child.setLayoutParams(layout);
    } else if (child != null && child.getWidth() < this.getWidth() * 2 / 3) {
      LinearLayout.LayoutParams layout = (LinearLayout.LayoutParams) child.getLayoutParams();
      if (layout == null)
        layout = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.FILL_PARENT);
      layout.width = this.getWidth() * 2 / 3;
      child.setLayoutParams(layout);
    }
  }

  public void refreshActiveView() {
    if (isRefreshing)
      return;
    isRefreshing = true;
    ensureAllChildrenLargeEnough();
    int x = 0;
    for (int i = 0; i < linearLayout.getChildCount() - 1; i++) {
      View child = linearLayout.getChildAt(i);
      if (i == activeView) {
        break;
      }
      x += child.getWidth();
    }
    if (x < 0)
      x = 0;
    if (this.getScrollX() != x) {
      mSmoothScrollTo(x, 0);
    }
    isRefreshing = false;
  }

  private long mLastScroll;

  public void mSmoothScrollTo(final int x, final int y) {
    if (SystemClock.uptimeMillis() < mLastScroll)
      return;
    float cx = this.getScrollX();
    float cy = this.getScrollY();

    int rateOfChange = 45;

    float dx = (x - cx) / rateOfChange;
    float dy = (y - cy) / rateOfChange;

    int delay = 0;

    Handler handler = new Handler();

    while (!equalWithinEpsilon(cx, x, dx * 2)
        || !equalWithinEpsilon(cy, y, dy * 2)) {
      cx += dx;
      cy += dy;
      final int fcx = (int) cx;
      final int fcy = (int) cy;
      handler.postDelayed(new Runnable() {
        @Override
        public void run() {
          SlidingScrollView.this.scrollTo(fcx, fcy);
          invalidate();
        }
      }, delay);
      delay += 5;
      if (delay > 1000) // just so we don't get stuck in an infinite loop
        break;
    }
    handler.postDelayed(new Runnable() {
      @Override
      public void run() {
        SlidingScrollView.this.scrollTo(x, y);
        invalidate();
      }
    }, delay);
    mLastScroll = SystemClock.uptimeMillis() + delay;
  }

  private boolean equalWithinEpsilon(double a, double b, double epsilon) {
    return Math.abs(a - b) <= Math.abs(epsilon);
  }

  @Override
  public boolean onTouch(View v, MotionEvent event) {
    int chosenOne = -1;
    for (int i = 0; i < linearLayout.getChildCount(); i++) {
      Rect rect = new Rect();
      linearLayout.getChildAt(i).getLocalVisibleRect(rect);
      int[] loc = new int[2];
      linearLayout.getChildAt(i).getLocationInWindow(loc);
      rect.offsetTo(loc[0], loc[1]);
      if (rect.contains((int) event.getX(), (int) event.getY())) {
        chosenOne = i;
        break;
      }
    }
    if (chosenOne != -1 && activeView != chosenOne) {
      this.setActiveView(chosenOne);
      return true;
    }
    return false;
  }
}

Java Source Code List

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