package cn.flightfeather.thirdapp.view;
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import android.content.Context;
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import android.util.AttributeSet;
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import android.util.Log;
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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.view.ViewTreeObserver;
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import android.widget.ImageView;
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import android.widget.LinearLayout;
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import android.widget.ScrollView;
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/**
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*自定义支持顶部布局上滑缩小，下滑放大的ScrollView
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*/
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public class MyScrollView extends ScrollView {
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private static final String TAG = "MyScrollView";
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private View headerView;
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private View imgView;
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private int imgOriginalHeight;
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private int maxHeight;
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private int minHeight = 0;
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private boolean mScaling = false; // 是否正在放大
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private float downYPoint = 0;
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private ScrollViewListener scrollViewListener;
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/**
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* 变化类型
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*/
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enum ChangeType {
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/*缩小，放大*/
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Narrow, Enlarge
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}
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public MyScrollView(Context context) {
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super(context);
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}
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public MyScrollView(Context context, AttributeSet attrs) {
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super(context, attrs);
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}
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public MyScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
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super(context, attrs, defStyleAttr);
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}
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public void setHeaderView(final View headerView, final View imgView) {
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this.headerView = headerView;
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this.imgView = imgView;
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ViewTreeObserver viewTreeObserver = headerView.getViewTreeObserver();
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viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
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@Override
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public void onGlobalLayout() {
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imgOriginalHeight = imgView.getHeight();
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maxHeight = headerView.getHeight();
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headerView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
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}
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});
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if (maxHeight <= 0 || minHeight < 0 || minHeight >= maxHeight) {
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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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// switch (ev.getAction()) {
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// case MotionEvent.ACTION_DOWN:
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// Log.w(TAG, "down .. Y == " + ev.getY());
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// downYPoint = ev.getY();
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// break;
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// case MotionEvent.ACTION_MOVE: {
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//// if (getScrollY() == 0) {
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// float distance = ev.getY() - downYPoint;
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// downYPoint = ev.getY();
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//
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// if (distance < 0 && canNarrow()) {
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// measureHeaderView(distance, ChangeType.Narrow);
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// cancelPendingInputEvents();
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// return true;
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// } else if (distance > 0 && canEnlarge()) {
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// measureHeaderView(distance, ChangeType.Enlarge);
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// return true;
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// }
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//// }
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// break;
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// }
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// case MotionEvent.ACTION_UP:
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// Log.e(TAG, "up .. Y == " + ev.getY());
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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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@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 (scrollViewListener != null) {
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scrollViewListener.onScrollChanged(this, l, t, oldl, oldt);
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}
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}
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public void setScrollViewListener(ScrollViewListener scrollViewListener) {
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this.scrollViewListener = scrollViewListener;
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}
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/**
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* 可以缩小
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*
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* @return
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*/
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private boolean canNarrow() {
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if (headerView == null) {
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return false;
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}
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return headerView.getHeight() > minHeight;
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}
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/**
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* 可以放大
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*
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* @return
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*/
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private boolean canEnlarge() {
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if (headerView == null) {
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return false;
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}
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return headerView.getHeight() < maxHeight;
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}
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/**
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* 根据移动的距离，重新计算headerView的高度
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*
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* @param distance
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* @return
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*/
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private void measureHeaderView(float distance, ChangeType changeType) {
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ViewGroup.LayoutParams params = headerView.getLayoutParams();
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params.height = headerView.getHeight() + (int) distance;
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if (params.height < minHeight) {
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params.height = minHeight;
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} else if (params.height > maxHeight) {
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params.height = maxHeight;
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} else if (params.height < 0) {
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params.height = 0;
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}
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Log.i(TAG, "headerView.height == " + params.height);
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headerView.setLayoutParams(params);
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measureImageView(params.height);
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}
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/**
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* 重新计算图片大小
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*
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* @param headerViewHeight
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*/
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private void measureImageView(int headerViewHeight) {
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if (imgView != null) {
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double multiple = (headerViewHeight * 1.00) / (maxHeight * 1.00);
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LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) imgView.getLayoutParams();
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params.height = (int) (imgOriginalHeight * multiple);
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if (params.height > imgOriginalHeight) {
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params.height = imgOriginalHeight;
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}
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imgView.setLayoutParams(params);
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}
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}
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public interface ScrollViewListener {
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void onScrollChanged(MyScrollView scrollView, int x, int y, int oldx, int oldy);
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}
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}
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