Android Open Source - Common-Library Slide Up Open Widget

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License

The source code is released under:
Apache License
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Java Source Code

package com.morgan.library.widget;
//from   w  w  w  . ja v a  2 s  . c om
import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.animation.BounceInterpolator;
import android.view.animation.DecelerateInterpolator;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.LinearLayout;
import android.widget.Scroller;

import com.morgan.library.R;

/**
 * ????????????????????View,???????????????????????ImageView?
 * 
 * @author Morgan.Ji
 * 
 */
public class SlideUpOpenWidget extends LinearLayout {

  private static final int DEFAULT_MINIMUM_VELOCITY = 2000;
  private static final int DEFAULT_ANIMATION_TIME = 800;
  private float mUpPercent = 0.5f;
  private float mStartY, mTempY;
  private Scroller mScroller;
  private boolean mMovable, mGone;
  private ImageView mImageView;
  private Context mContext;
  private OnSlidePageGoneListener mSlidePageGoneListener;
  private VelocityTracker mVelocityTracker;
  private float mMaximumVelocity;
  private int mMinimumVelocity;

  public SlideUpOpenWidget(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.mContext = context;
    TypedArray ta = context.obtainStyledAttributes(attrs,
        R.styleable.SlideUpOpenWidget);
    mScroller = new Scroller(context, new BounceInterpolator());
    mImageView = new ImageView(context);
    int imageResource = ta.getResourceId(
        R.styleable.SlideUpOpenWidget_coverImage, -1);
    if (imageResource != -1) {
      mImageView.setImageResource(imageResource);
    } else {
      this.setVisibility(View.GONE);
    }
    mImageView.setScaleType(ScaleType.FIT_XY);
    mImageView.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
        LayoutParams.MATCH_PARENT));
    this.addView(mImageView);
    ta.recycle();
    final ViewConfiguration configuration = ViewConfiguration.get(context);
    mMinimumVelocity = DEFAULT_MINIMUM_VELOCITY;
    mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
  }

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    obtainVelocityTracker(event);
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
      if (!mScroller.isFinished()) {
        mScroller.abortAnimation();
      }
      mStartY = event.getY();
      break;
    case MotionEvent.ACTION_MOVE:
      mTempY = event.getY();
      if (mTempY < mStartY) {
        mMovable = true;
      } else {
        mStartY = mTempY;
      }
      if (mMovable) {
        scrollTo(0, (int) (mStartY - mTempY));
      }
      break;
    case MotionEvent.ACTION_UP:
      if (mMovable) {
        mMovable = false;
        final VelocityTracker velocityTracker = mVelocityTracker;
        velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
        int initialVelocity = (int) velocityTracker.getYVelocity();
        if ((Math.abs(initialVelocity) > mMinimumVelocity)
            && getChildCount() > 0) {
          mScroller = new Scroller(mContext,
              new DecelerateInterpolator());
          mScroller.startScroll(0, (int) (mStartY - mTempY), 0,
              (int) (getHeight() - (mStartY - mTempY)),
              DEFAULT_ANIMATION_TIME);
          invalidate();
          mGone = true;
        } else {
          mTempY = event.getY();
          if ((mStartY - mTempY) > getHeight() * mUpPercent) {
            mScroller = new Scroller(mContext,
                new DecelerateInterpolator());
            mScroller.startScroll(0, (int) (mStartY - mTempY), 0,
                (int) (getHeight() - (mStartY - mTempY)),
                DEFAULT_ANIMATION_TIME);
            invalidate();
            mGone = true;
          } else {
            mScroller.startScroll(0, (int) (mStartY - mTempY), 0,
                (int) (mTempY - mStartY),
                DEFAULT_ANIMATION_TIME);
            invalidate();
          }
        }
      }
      releaseVelocityTracker();
      break;
    default:
      break;
    }
    return true;
  }

  @Override
  public void computeScroll() {
    if (!mScroller.isFinished()) {
      if (mScroller.computeScrollOffset()) {
        int oldY = getScrollY();
        int y = mScroller.getCurrY();
        if (oldY != y) {
          scrollTo(0, y);
        }
        invalidate();
        return;
      }
    } else {
      if (mGone) {
        this.setVisibility(View.GONE);
        if (null != mSlidePageGoneListener) {
          mSlidePageGoneListener.onSlidePageGone();
        }
      }
    }
  }

  public interface OnSlidePageGoneListener {
    public void onSlidePageGone();
  }

  public void setOnSlidePageGoneListener(
      OnSlidePageGoneListener mSlidePageGoneListener) {
    this.mSlidePageGoneListener = mSlidePageGoneListener;
  }

  private void obtainVelocityTracker(MotionEvent event) {
    if (mVelocityTracker == null) {
      mVelocityTracker = VelocityTracker.obtain();
    }
    mVelocityTracker.addMovement(event);
  }

  private void releaseVelocityTracker() {
    if (mVelocityTracker != null) {
      mVelocityTracker.recycle();
      mVelocityTracker = null;
    }
  }
}
Java Source Code List
