package cn.flightfeather.thirdapp.view;
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import android.animation.ObjectAnimator;
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import android.animation.ValueAnimator;
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import android.annotation.SuppressLint;
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import android.content.Context;
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import android.util.AttributeSet;
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import android.view.MotionEvent;
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import android.view.View;
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import android.view.ViewGroup;
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import android.widget.ScrollView;
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public class HeadZoomScrollView extends ScrollView {
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public HeadZoomScrollView(Context context) {
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super(context);
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}
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public HeadZoomScrollView(Context context, AttributeSet attrs) {
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super(context, attrs);
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}
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public HeadZoomScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
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super(context, attrs, defStyleAttr);
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}
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//用于记录下拉位置
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private float y=0f;
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//zoomView原本的宽高
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private int zoomViewWidth = 0;
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private int zoomViewHeight = 0;
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//是否正在放大
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private boolean mScaling = false;
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//放大的view，默认为第一个子view
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private View zoomView;
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public void setZoomView(View zoomView) {
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this.zoomView = zoomView;
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}
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//滑动放大系数，系数越大，滑动时放大程度越大
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private float mScaleRatio = 0.4f;
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public void setmScaleRatio(float mScaleRatio) {
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this.mScaleRatio = mScaleRatio;
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}
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//最大的放大倍数
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private float mScaleTimes = 2f;
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public void setmScaleTimes(int mScaleTimes) {
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this.mScaleTimes = mScaleTimes;
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}
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//回弹时间系数，系数越小，回弹越快
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private float mReplyRatio = 0.5f;
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public void setmReplyRatio(float mReplyRatio) {
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this.mReplyRatio = mReplyRatio;
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}
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@SuppressLint("NewApi")
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@Override
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protected void onFinishInflate() {
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super.onFinishInflate();
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// 不可过度滚动，否则上移后下拉会出现部分空白的情况
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setOverScrollMode(OVER_SCROLL_NEVER);
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// 获得默认第一个view
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if (getChildAt(0) != null && getChildAt(0) instanceof ViewGroup && zoomView == null) {
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ViewGroup vg = (ViewGroup) getChildAt(0);
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if (vg.getChildCount() > 0) {
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zoomView = vg.getChildAt(0);
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}
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}
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}
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@Override
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public boolean onTouchEvent(MotionEvent ev) {
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if (zoomViewWidth <= 0 || zoomViewHeight <=0) {
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zoomViewWidth = zoomView.getMeasuredWidth();
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zoomViewHeight = zoomView.getMeasuredHeight();
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}
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if (zoomView == null || zoomViewWidth <= 0 || zoomViewHeight <= 0) {
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return super.onTouchEvent(ev);
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}
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switch (ev.getAction()) {
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case MotionEvent.ACTION_MOVE:
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if (!mScaling) {
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if (getScrollY() == 0) {
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y = ev.getY();//滑动到顶部时，记录位置
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} else {
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break;
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}
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}
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int distance = (int) ((ev.getY() - y)*mScaleRatio);
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if (distance < 0) break;//若往下滑动
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mScaling = true;
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setZoom(distance);
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return true;
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case MotionEvent.ACTION_UP:
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mScaling = false;
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replyView();
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break;
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}
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return super.onTouchEvent(ev);
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}
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/**放大view*/
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private void setZoom(float s) {
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float scaleTimes = (float) ((zoomViewWidth+s)/(zoomViewWidth*1.0));
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// 如超过最大放大倍数，直接返回
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if (scaleTimes > mScaleTimes) return;
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ViewGroup.LayoutParams layoutParams = zoomView.getLayoutParams();
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layoutParams.width = (int) (zoomViewWidth + s);
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layoutParams.height = (int)(zoomViewHeight*((zoomViewWidth+s)/zoomViewWidth));
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// 设置控件水平居中
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((MarginLayoutParams) layoutParams).setMargins(-(layoutParams.width - zoomViewWidth) / 2, 0, 0, 0);
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zoomView.setLayoutParams(layoutParams);
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}
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/**回弹*/
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@SuppressLint("NewApi")
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private void replyView() {
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final float distance = zoomView.getMeasuredWidth() - zoomViewWidth;
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// 设置动画
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ValueAnimator anim = ObjectAnimator.ofFloat(distance, 0.0F).setDuration((long) (distance * mReplyRatio));
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anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
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@Override
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public void onAnimationUpdate(ValueAnimator animation) {
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setZoom((Float) animation.getAnimatedValue());
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}
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});
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anim.start();
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}
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@Override
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protected void onScrollChanged(int l, int t, int oldl, int oldt) {
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super.onScrollChanged(l, t, oldl, oldt);
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if (onScrollListener!=null) onScrollListener.onScroll(l,t,oldl,oldt);
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}
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private OnScrollListener onScrollListener;
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public void setOnScrollListener(OnScrollListener onScrollListener) {
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this.onScrollListener = onScrollListener;
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}
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/**滑动监听*/
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public interface OnScrollListener{
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void onScroll(int scrollX,int scrollY,int oldScrollX, int oldScrollY);
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}
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}
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