package com.marshalchen.common.uimodule.huitanScrollView;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.TranslateAnimation;
import android.widget.ScrollView;
import com.marshalchen.common.uimodule.R;
/**
* 自定义ScrollView
*
* @author markmjw
* @date 2013-09-13
*/
public class PullScrollView extends ScrollView {
/** 阻尼系数,越小阻力就越大. */
private static final float SCROLL_RATIO = 0.5f;
/** 滑动至翻转的距离. */
private static final int TURN_DISTANCE = 100;
/** 头部view. */
private View mHeader;
/** 头部view高度. */
private int mHeaderHeight;
/** 头部view显示高度. */
private int mHeaderVisibleHeight;
/** ScrollView的content view. */
private View mContentView;
/** ScrollView的content view矩形. */
private Rect mContentRect = new Rect();
/** 首次点击的Y坐标. */
private float mTouchDownY;
/** 是否关闭ScrollView的滑动. */
private boolean mEnableTouch = false;
/** 是否开始移动. */
private boolean isMoving = false;
/** 是否移动到顶部位置. */
private boolean isTop = false;
/** 头部图片初始顶部和底部. */
private int mInitTop, mInitBottom;
/** 头部图片拖动时顶部和底部. */
private int mCurrentTop, mCurrentBottom;
/** 状态变化时的监听器. */
private OnTurnListener mOnTurnListener;
private enum State {
/**顶部*/
UP,
/**底部*/
DOWN,
/**正常*/
NORMAL
}
/** 状态. */
private State mState = State.NORMAL;
public PullScrollView(Context context) {
super(context);
init(context, null);
}
public PullScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}
public PullScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context, attrs);
}
private void init(Context context, AttributeSet attrs) {
// set scroll mode
setOverScrollMode(OVER_SCROLL_NEVER);
if (null != attrs) {
TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.PullScrollView);
if (ta != null) {
mHeaderHeight = (int) ta.getDimension(R.styleable.PullScrollView_headerHeight, -1);
mHeaderVisibleHeight = (int) ta.getDimension(R.styleable
.PullScrollView_headerVisibleHeight, -1);
ta.recycle();
}
}
}
/**
* 设置Header
*
* @param view
*/
public void setHeader(View view) {
mHeader = view;
}
/**
* 设置状态改变时的监听器
*
* @param turnListener
*/
public void setOnTurnListener(OnTurnListener turnListener) {
mOnTurnListener = turnListener;
}
@Override
protected void onFinishInflate() {
if (getChildCount() > 0) {
mContentView = getChildAt(0);
}
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (getScrollY() == 0) {
isTop = true;
}
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
mTouchDownY = ev.getY();
mCurrentTop = mInitTop = mHeader.getTop();
mCurrentBottom = mInitBottom = mHeader.getBottom();
}
return super.onInterceptTouchEvent(ev);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (mContentView != null) {
doTouchEvent(ev);
}
// 禁止控件本身的滑动.
return mEnableTouch || super.onTouchEvent(ev);
}
/**
* 触摸事件处理
*
* @param event
*/
private void doTouchEvent(MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_MOVE:
doActionMove(event);
break;
case MotionEvent.ACTION_UP:
// 回滚动画
if (isNeedAnimation()) {
rollBackAnimation();
}
if (getScrollY() == 0) {
mState = State.NORMAL;
}
isMoving = false;
mEnableTouch = false;
break;
default:
break;
}
}
/**
* 执行移动动画
*
* @param event
*/
private void doActionMove(MotionEvent event) {
// 当滚动到顶部时，将状态设置为正常，避免先向上拖动再向下拖动到顶端后首次触摸不响应的问题
if (getScrollY() == 0) {
mState = State.NORMAL;
// 滑动经过顶部初始位置时，修正Touch down的坐标为当前Touch点的坐标
if (isTop) {
isTop = false;
mTouchDownY = event.getY();
}
}
float deltaY = event.getY() - mTouchDownY;
// 对于首次Touch操作要判断方位：UP OR DOWN
if (deltaY < 0 && mState == State.NORMAL) {
mState = State.UP;
} else if (deltaY > 0 && mState == State.NORMAL) {
mState = State.DOWN;
}
if (mState == State.UP) {
deltaY = deltaY < 0 ? deltaY : 0;
isMoving = false;
mEnableTouch = false;
} else if (mState == State.DOWN) {
if (getScrollY() <= deltaY) {
mEnableTouch = true;
isMoving = true;
}
deltaY = deltaY < 0 ? 0 : deltaY;
}
if (isMoving) {
// 初始化content view矩形
if (mContentRect.isEmpty()) {
// 保存正常的布局位置
mContentRect.set(mContentView.getLeft(), mContentView.getTop(), mContentView.getRight(),
mContentView.getBottom());
}
// 计算header移动距离(手势移动的距离*阻尼系数*0.5)
float headerMoveHeight = deltaY * 0.5f * SCROLL_RATIO;
mCurrentTop = (int) (mInitTop + headerMoveHeight);
mCurrentBottom = (int) (mInitBottom + headerMoveHeight);
// 计算content移动距离(手势移动的距离*阻尼系数)
float contentMoveHeight = deltaY * SCROLL_RATIO;
// 修正content移动的距离，避免超过header的底边缘
int headerBottom = mCurrentBottom - mHeaderVisibleHeight;
int top = (int) (mContentRect.top + contentMoveHeight);
int bottom = (int) (mContentRect.bottom + contentMoveHeight);
if (top <= headerBottom) {
// 移动content view
mContentView.layout(mContentRect.left, top, mContentRect.right, bottom);
// 移动header view
mHeader.layout(mHeader.getLeft(), mCurrentTop, mHeader.getRight(), mCurrentBottom);
}
}
}
private void rollBackAnimation() {
TranslateAnimation tranAnim = new TranslateAnimation(0, 0,
Math.abs(mInitTop - mCurrentTop), 0);
tranAnim.setDuration(200);
mHeader.startAnimation(tranAnim);
mHeader.layout(mHeader.getLeft(), mInitTop, mHeader.getRight(), mInitBottom);
// 开启移动动画
TranslateAnimation innerAnim = new TranslateAnimation(0, 0, mContentView.getTop(), mContentRect.top);
innerAnim.setDuration(200);
mContentView.startAnimation(innerAnim);
mContentView.layout(mContentRect.left, mContentRect.top, mContentRect.right, mContentRect.bottom);
mContentRect.setEmpty();
// 回调监听器
if (mCurrentTop > mInitTop + TURN_DISTANCE && mOnTurnListener != null){
mOnTurnListener.onTurn();
}
}
/**
* 是否需要开启动画
*/
private boolean isNeedAnimation() {
return !mContentRect.isEmpty() && isMoving;
}
/**
* 翻转事件监听器
*
* @author markmjw
*/
public interface OnTurnListener {
/**
* 翻转回调方法
*/
public void onTurn();
}
}