仿百度地图抽屉拖拽效果源码

package com.cn.scrolllayout.view; import android.animation.Animator; import android.animation.ValueAnimator; import android.content.Context; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.animation.LinearInterpolator; import com.cn.scrolllayout.LogUtils; import com.cn.scrolllayout.ScreenUtils; /** * Created by yunzhao.liu on 2018/6/20 * <p> * ScrollTo和ScrollBy滑动的是view的显示内容，并不改变view的坐标(即：ScrollLayout里的内容) * ScrollBy:它是基于当前位置的相对滑动 * x和y不是坐标点，是偏移量，坐标系是左正上正 */ public class ScrollLayout extends ViewGroup { public ScrollLayout(Context context) { this(context, null); } public ScrollLayout(Context context, AttributeSet attrs) { this(context, attrs, 0); } public ScrollLayout(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(context); } public final static int STATUS_DEFAULT = 0; public final static int STATUS_EXTEND = 1; public final static int STATUS_CLOSE = 2; public final static int STATUS_ING = 3;//滑动中 private int touchSlop; private int slideSlop; private int offsetB; private ValueAnimator animator; private int width; private int height; private int offsetY; private int offsetExtend; private int offsetClose;//是负数 private int offsetDefault; private int child_default_height; private float dX, dY;//TouchEvent_ACTION_DOWN坐标(dX,dY) private float lastY;//TouchEvent最后一次坐标(lastX,lastY) private boolean isEventValid = true;//本次touch事件是否有效 private boolean isMoveValid; private int status; private int curY, finalY; private float factor; private void init(Context context) { touchSlop = ViewConfiguration.get(context).getScaledTouchSlop(); slideSlop = ScreenUtils.dpToPxInt(context, 45); offsetB = ScreenUtils.dpToPxInt(context, 40); animator = ValueAnimator.ofFloat(0f, 1f); animator.setDuration(200); animator.setInterpolator(new LinearInterpolator()); animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { factor = (float) animation.getAnimatedValue(); //这里打印会先打印出：1，然后再从0-1打印，因为每次在start时，都会先调用stop LogUtils.i("liuyzz--onAnimation--:", "" + factor); //curY可为负数或正数 float scrollY = curY + (finalY - curY) * factor; scrollTo(0, (int) scrollY); postInvalidate(); if (listener != null) { listener.onScrollChange(STATUS_ING); //大于设置的展开距离后才设置颜色渐变 if (getScrollY() > offsetB) { listener.onScrollProgress(255 * getScrollY() / offsetY); } else { listener.onScrollProgress(0); } } } }); animator.addListener(new Animator.AnimatorListener() { @Override public void onAnimationStart(Animator animation) { } //动画全部更新完成后再走此方法：addUpdateListener->onAnimationEnd @Override public void onAnimationEnd(Animator animation) { factor = 1;//容错处理，正常情况下addUpdateListener执行完成后factor是1 if (listener != null) { listener.onScrollChange(status); } } @Override public void onAnimationCancel(Animator animation) { } @Override public void onAnimationRepeat(Animator animation) { } }); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); width = MeasureSpec.getSize(widthMeasureSpec); height = MeasureSpec.getSize(heightMeasureSpec); //界面下边显示出来的子View的高度 child_default_height = ScreenUtils.dpToPxInt(getContext(), 210); offsetY = height - child_default_height; offsetExtend = offsetY - offsetB; offsetClose = offsetY + offsetB - height;//负数 向下移动到剩下40dp的高度 offsetDefault = 0; int count = getChildCount(); for (int i = 0; i < count; i++) { View child = getChildAt(i); measureChild(child, widthMeasureSpec, heightMeasureSpec); } setMeasuredDimension(width, height); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int count = getChildCount(); if (count > 0) { int top = offsetY;//第一个View距顶高度 for (int i = 0; i < count; i++) { View child = getChildAt(i); int childHeight = child.getMeasuredHeight(); //必须有三个孩子，多了不显示 switch (i) { case 0: child.layout(0, top, width, top + childHeight); top += childHeight; break; case 1: //下：需要用屏幕高度-状态栏的高度(40dp)-第一个孩子的高度 child.layout(0, top, width, top + height - offsetB - getChildAt(0).getMeasuredHeight()); top += childHeight; break; case 2: child.layout(0, offsetY, width, offsetY + childHeight); break; } } } } @Override public boolean dispatchTouchEvent(MotionEvent ev) { //手势坐标系：下正右正 float eX = ev.getX(); float eY = ev.getY(); switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: dX = eX; lastY = dY = eY; isMoveValid = false; isEventValid = true; //首次进入getScrollY为0，当eY点击区域在offsetY距离下边，则进入 //当点击距离在offsetY上边则进入else if (getScrollY() + eY > offsetY) { //当动画正在执行时，事件不往View中传递 if (!(factor == 0 || factor == 1)) { isEventValid = false; } else { //当子View为非滑动事件如TextView,LinearLayoutd等会调用它们的onTouchEvent的所有事件 //当子View为滑动事件如ListView,RecyclerView等不会调用onTouchEvent的Down事件，而是从Move事件开始嗲用 super.dispatchTouchEvent(ev); } return true; } return false; case MotionEvent.ACTION_MOVE: //当动画正在执行时，点击滑动不起作用 if (!isEventValid) return false; //下滑offset就是负数，上滑就是正数 int offset = (int) (lastY - eY); lastY = eY; if ((status == STATUS_EXTEND || status == STATUS_CLOSE)