package com.zhengsr.tablib.view.flow;
import android.content.Context;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewParent;
import android.widget.Scroller;
/**
* @author by zhengshaorui on 2019/10/8
* Describe: 滚动类，用来移动
*/
class ScrollFlowLayout extends FlowLayout {
private static final String TAG = "ScrollFlowLayout";
private int mTouchSlop;
private float mLastPos;
private float mMovePos;
protected int mRightBound;
protected int mBottomRound;
private boolean isCanMove;
private int mScreenWidth;
private int mScreenHeight;
private VelocityTracker mVelocityTracker;
private Scroller mScroller;
private int mCurScrollPos;
private int mMaximumVelocity;
private int mMinimumVelocity;
protected boolean isMove;
protected int mWidth;
protected int mHeight;
public ScrollFlowLayout(Context context) {
this(context, null);
}
public ScrollFlowLayout(Context context, @Nullable AttributeSet attrs) {
this(context, attrs, 0);
}
public ScrollFlowLayout(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
mScreenWidth = getResources().getDisplayMetrics().widthPixels;
mScreenHeight = getResources().getDisplayMetrics().heightPixels;
mScroller = new Scroller(context);
mMaximumVelocity = ViewConfiguration.get(context).getScaledMaximumFlingVelocity();
mMinimumVelocity = ViewConfiguration.get(context).getScaledMinimumFlingVelocity();
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
int count = getChildCount();
//拿到有边界
if (count > 0) {
View child = getChildAt(count - 1);
mRightBound = child.getRight() + getPaddingRight();
mBottomRound = child.getBottom() + getPaddingBottom();
}
/**
* TabFlowLayout 或者 LabelFlowLayout 的竖向滚动
*/
//todo 这是什么魔性 if else 找机会改一下
if (isVerticalMove()){
if (mViewHeight < mScreenHeight){
if (mBottomRound > mViewHeight){
isCanMove = true;
}else{
isCanMove = false;
}
mHeight = mViewHeight;
}else{
//再确认一遍
if (mBottomRound > mScreenHeight){
isCanMove = true;
}
mHeight = mScreenHeight;
//需要减去actionbar 和 状态栏的高度
mHeight = mHeight - getActionBarHeight(getContext()) - getStatusBarHeight();
}
if (!isLabelAutoScroll() || !isTabAutoScroll()){
isCanMove = false;
}
}else{
//TabFlowLayout 横向布局
if (!isVertical()) {
//如果是固定宽度
if (mVisualCount != -1){
if (getChildCount() > mVisualCount){
isCanMove = true;
}else{
isCanMove = false;
}
mWidth = mViewWidth;
}else {
//说明控件没有满屏或者固定宽度
if (mViewWidth < mScreenWidth) {
if (mRightBound > mViewWidth) {
isCanMove = true;
} else {
isCanMove = false;
}
mWidth = mViewWidth;
} else {
//再确认一遍
if (mRightBound > mScreenWidth) {
isCanMove = true;
}
mWidth = mScreenWidth;
}
}
if (!isTabAutoScroll()) {
isCanMove = false;
}
}
}
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (!isCanMove){
return super.onInterceptTouchEvent(ev);
}
final ViewParent parent = getParent();
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
if (isVertical()){
mLastPos = ev.getY();
}else {
mLastPos = ev.getX();
}
//拿到上次的down坐标
if (isVertical()){
mMovePos = ev.getY();
}else {
mMovePos = ev.getX();
}
if (mScroller != null && !mScroller.isFinished()) {
mScroller.abortAnimation();
}
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
mVelocityTracker = VelocityTracker.obtain();
mVelocityTracker.addMovement(ev);
//如果能滚动，应该要屏蔽父控件的触摸事件
if (parent != null) {
parent.requestDisallowInterceptTouchEvent(true);
}
break;
case MotionEvent.ACTION_MOVE:
float offset;
if (isVerticalMove()){
offset = ev.getY() - mLastPos;
}else{
offset = ev.getX() - mLastPos;
}
if (Math.abs(offset) >= mTouchSlop) {
if (parent != null) {
parent.requestDisallowInterceptTouchEvent(true);
}
if (mVelocityTracker == null){
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
//由父控件接管触摸事件
return true;
}
if (isVerticalMove()){
mLastPos = ev.getY();
}else {
mLastPos = ev.getX();
}
break;
default:
break;
}
return super.onInterceptTouchEvent(ev);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
final ViewParent parent = getParent();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_MOVE:
//scroller 向右为负，向左为正
int offset;
if (isVerticalMove()){
offset = (int) (mMovePos - event.getY());
}else {
offset = (int) (mMovePos - event.getX());
}
if (Math.abs(offset) > mTouchSlop){
if (parent != null) {
parent.requestDisallowInterceptTouchEvent(true);
}
}
int scrollPos ;
if (isVerticalMove()){
scrollPos = getScrollY();
}else{
scrollPos = getScrollX();
}
/**
* 判断边界
*/
if (scrollPos + offset <= 0) {
scrollTo(0, 0);
return true;
}
if (isVerticalMove()){
if (scrollPos +offset >= mBottomRound - mHeight){
scrollTo(0,mBottomRound - mHeight);
return true;
}
scrollBy(0, offset);
}else{
if (scrollPos +offset >= mRightBound - mWidth) {
scrollTo(mRightBound - mWidth, 0);
return true;
}
scrollBy(offset, 0);
}
isMove = true;
if (isVerticalMove()){
mMovePos = event.getY();
}else {
mMovePos = event.getX();
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mVelocityTracker.computeCurrentVelocity(1000,mMaximumVelocity);
int velocityPos ;
if (isVerticalMove()){
velocityPos = (int) mVelocityTracker.getYVelocity();
}else{
velocityPos = (int) mVelocityTracker.getXVelocity();
}
if (Math.abs(velocityPos) >= mMinimumVelocity) {
if (isVerticalMove()){
mCurScrollPos = getScrollY();
mScroller.fling(0,mCurScrollPos,0,velocityPos,
0,0,0,getHeight());
}else {
mCurScrollPos = getScrollX();
mScroller.fling(mCurScrollPos, 0, velocityPos,
0, 0, getWidth(), 0, 0);
}
if (mVelocityTracker != null) {
mVelocityTracker.clear();
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
break;
default:
break;
}
return super.onTouchEvent(event);
}
@Override
public void computeScroll() {
super.computeScroll();
if (mScroller.computeScrollOffset()){
int offset;
if (isVerticalMove()){
offset = mCurScrollPos - mScroller.getCurrY();
}else {
offset = mCurScrollPos - mScroller.getCurrX();
}
// 超出边界，进行修正
int scrollPos;
if (isVerticalMove()){
if (getScrollY() + offset >= mBottomRound - mHeight) {
offset = mBottomRound - mHeight - getScrollY();
}
// 超出边界，进行修正
if (getScrollY() + offset <= 0) {
offset = -getScrollY();
}
scrollBy(0,offset);
}else{
if (getScrollX() + offset >= mRightBound - mWidth) {
offset = mRightBound - mWidth - getScrollX();
}
// 超出边界，进行修正
if (getScrollX() + offset <= 0) {
offset = -getScrollX();
}
scrollBy(offset,0);
}
postInvalidate();
}
}
public int getViewWidth(){
return mWidth;
}
public boolean isCanMove() {
return isCanMove;
}
public boolean isMove() {
return isMove;
}
public void setMove(boolean move) {
isMove = move;
}
/**
* 获取状态栏的高度
* @return
*/
private int getStatusBarHeight(){
int result = 0;
int resourceId = this.getResources().getIdentifier("status_bar_height", "dimen", "android");
if (resourceId > 0) {
result = this.getResources().getDimensionPixelSize(resourceId);
}
return result;
}
/**
* 拿到 actionbar 的高度
* @param context
* @return
*/
private int getActionBarHeight(Context context){
TypedValue tv = new TypedValue();
if (context.getTheme().resolveAttribute(android.R.attr.actionBarSize,tv,true)){
return TypedValue.complexToDimensionPixelSize(tv.data,
context.getResources().getDisplayMetrics());
}
return 0;
}
public boolean isLabelAutoScroll(){
return true;
}
public boolean isTabAutoScroll(){
return true;
}
}
