又是新的一年， 又开始了打工人生活， 希望大家在新的一年都能达到自己的预期， 杠把得。
最近项目里会用到侧滑删除的效果， 类似QQ消息侧滑，因为没找到啥比较合适的轮子，功能也比较单一，所以直接手写了。
看一下效果：
007.gif
在xml中怎么使用：
<!--自定义侧滑容器-->
<com.example.sliddemo.SlideLayout
android:id="@+id/slidelayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<!--左部分-->
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="100dp"
android:background="#000000"
>
<androidx.appcompat.widget.AppCompatTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="自定义布局"
android:layout_centerInParent="true"
android:textColor="#ffffff"
/>
</RelativeLayout>
<!--右部分-->
<androidx.appcompat.widget.AppCompatTextView
android:id="@+id/tv_delete"
android:layout_width="140dp"
android:layout_height="match_parent"
android:text="删除"
android:textColor="#ffffff"
android:background="#ff0000"
android:gravity="center"
/>
</com.example.sliddemo.SlideLayout>
再记录一下思路：
1.侧滑效果需要包含两部分， 左边显示区域， 右边隐藏区域， 滑动时显示右部分。
2.滑动未完成时根据滑动距离， 自动滚动到合适位置。
3.单击时不能拦截事件， 滚动时拦截事件。
4.滚动时强制父容器不拦截事件（在RecyclerView中如果不强制 竖直滑动和水平滑动会同时发生）；
代码根据思路写：
1.新建SlideLayout继承ViewGroup， 然后在SlideLayout中放入两个View，这就是左右两部分，
再onMeasure中测量放入View的大小， 在onLayout中将View显示在界面上，代码如下：
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int count = getChildCount();
if(count != 2){
throw new RuntimeException("only can host 2 direct child view");
}
measureChildren(widthMeasureSpec, heightMeasureSpec);
childOne = getChildAt(0);
childTwo = getChildAt(1);
childTwo.measure(MeasureSpec.makeMeasureSpec(childTwo.getMeasuredWidth(), MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(childOne.getMeasuredHeight(), MeasureSpec.EXACTLY));
int ps = getPaddingStart();
int pt = getPaddingTop();
int pe = getPaddingEnd();
int pb = getPaddingBottom();
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int slideWith = ps + pe;
int slideHigh = pt + pb;
switch (widthMode){
case MeasureSpec.EXACTLY:
slideWith = widthSize;
break;
case MeasureSpec.UNSPECIFIED:
case MeasureSpec.AT_MOST:
for (int i=0; i<count; i++){
View child = getChildAt(i);
slideWith += child.getMeasuredWidth();
}
break;
default:
break;
}
switch (heightMode){
case MeasureSpec.EXACTLY:
slideHigh = heightSize;
break;
case MeasureSpec.UNSPECIFIED:
case MeasureSpec.AT_MOST:
slideHigh += Math.max(childOne.getMeasuredHeight(), childTwo.getMeasuredHeight());
break;
default:
break;
}
setMeasuredDimension(slideWith, slideHigh);
}
@Override
protected void onLayout(boolean b, int l, int i1, int i2, int i3) {
int ps = getPaddingStart();
int pt = getPaddingTop();
int pb = getPaddingBottom();
int childOneWith = childOne.getMeasuredWidth();
int childOneHigh = childOne.getMeasuredHeight();
int childTwoWith = childTwo.getMeasuredWidth();
int childTwoHigjh = childTwo.getMeasuredHeight();
childOne.layout(ps, pt, ps + childOneWith, pt + childOneHigh + pb);
childTwo.layout(ps + childOneWith, pt, ps + childOneWith + childTwoWith, pt + Math.max(childOneHigh, childTwoHigjh) + pb);
scrollLimitSize = childTwoWith;
}
2，3，4：
在onInterceptTouchEvent中进行事件拦截， 在onTouchEvent中进行View的滚动，在用户手指抬起时记录滚动位置， 并使用Scroller进行自动滚动，代码如下:
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
isClick = true;
startX = (int) event.getX();
startY = (int) event.getY();
return false;
case MotionEvent.ACTION_MOVE:
isClick = false;
return true;
case MotionEvent.ACTION_UP:
return !isClick;
default:
break;
}
return false;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
getParent().requestDisallowInterceptTouchEvent(true);
break;
case MotionEvent.ACTION_MOVE:
int endY = (int) (event.getY() - startY);
int endX = (int) (event.getX() - startX);
if((Math.abs(endY) > Math.abs(endX)) && !canScrooll){
getParent().requestDisallowInterceptTouchEvent(false);
resetScroll();
}else{
getParent().requestDisallowInterceptTouchEvent(true);
canScrooll = true;
}
if(canScrooll){
int scroll = currentScroll + endX;
if(scroll < -scrollLimitSize){
scroll = -scrollLimitSize;
}else if(scroll > 0){
scroll = 0;
}
scrollTo(- scroll, 0);
}
break;
case MotionEvent.ACTION_UP:
int divide = scrollLimitSize >> 1;
if (getScrollX() > divide){
scroller.startScroll(getScrollX(), 0, scrollLimitSize - getScrollX(), 0, TIME);
}else{
scroller.startScroll(getScrollX(), 0, - getScrollX(), 0, TIME);
}
invalidate();
currentScroll = -getScrollX();
getParent().requestDisallowInterceptTouchEvent(false);
canScrooll = false;
return !isClick;
default:
break;
}
return true;
}
@Override
public void computeScroll() {
super.computeScroll();
if(scroller.computeScrollOffset()){
scrollTo(scroller.getCurrX(), scroller.getCurrY());
invalidate();
}
}
重点就这两个， 下面贴全部代码， 就一个类：
public class SlideLayout extends ViewGroup {
private static final int TIME = 100;
private View childOne, childTwo;
//最大滑动距离
private int scrollLimitSize;
private int startX;
private int startY;
private Scroller scroller;
//当前滑动位置
private int currentScroll;
private boolean isClick = true;
private boolean canScrooll;
public SlideLayout(Context context) {
super(context);
init(context);
}
public SlideLayout(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public SlideLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
private void init(Context context){
scroller = new Scroller(context);
}
/**
* 展开
*/
public void open(){
scroller.startScroll(getScrollX(), 0, scrollLimitSize - getScrollX(), 0, TIME);
invalidate();
}
/**
* 收起
*/
public void put(){
scroller.startScroll(getScrollX(), 0, -getScrollX(), 0, TIME);
invalidate();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int count = getChildCount();
if(count != 2){
throw new RuntimeException("only can host 2 direct child view");
}
measureChildren(widthMeasureSpec, heightMeasureSpec);
childOne = getChildAt(0);
childTwo = getChildAt(1);
childTwo.measure(MeasureSpec.makeMeasureSpec(childTwo.getMeasuredWidth(), MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(childOne.getMeasuredHeight(), MeasureSpec.EXACTLY));
int ps = getPaddingStart();
int pt = getPaddingTop();
int pe = getPaddingEnd();
int pb = getPaddingBottom();
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int slideWith = ps + pe;
int slideHigh = pt + pb;
switch (widthMode){
case MeasureSpec.EXACTLY:
slideWith = widthSize;
break;
case MeasureSpec.UNSPECIFIED:
case MeasureSpec.AT_MOST:
for (int i=0; i<count; i++){
View child = getChildAt(i);
slideWith += child.getMeasuredWidth();
}
break;
default:
break;
}
switch (heightMode){
case MeasureSpec.EXACTLY:
slideHigh = heightSize;
break;
case MeasureSpec.UNSPECIFIED:
case MeasureSpec.AT_MOST:
slideHigh += Math.max(childOne.getMeasuredHeight(), childTwo.getMeasuredHeight());
break;
default:
break;
}
setMeasuredDimension(slideWith, slideHigh);
}
@Override
protected void onLayout(boolean b, int l, int i1, int i2, int i3) {
int ps = getPaddingStart();
int pt = getPaddingTop();
int pb = getPaddingBottom();
int childOneWith = childOne.getMeasuredWidth();
int childOneHigh = childOne.getMeasuredHeight();
int childTwoWith = childTwo.getMeasuredWidth();
int childTwoHigjh = childTwo.getMeasuredHeight();
childOne.layout(ps, pt, ps + childOneWith, pt + childOneHigh + pb);
childTwo.layout(ps + childOneWith, pt, ps + childOneWith + childTwoWith, pt + Math.max(childOneHigh, childTwoHigjh) + pb);
scrollLimitSize = childTwoWith;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
isClick = true;
startX = (int) event.getX();
startY = (int) event.getY();
return false;
case MotionEvent.ACTION_MOVE:
isClick = false;
return true;
case MotionEvent.ACTION_UP:
return !isClick;
default:
break;
}
return false;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
getParent().requestDisallowInterceptTouchEvent(true);
break;
case MotionEvent.ACTION_MOVE:
int endY = (int) (event.getY() - startY);
int endX = (int) (event.getX() - startX);
if((Math.abs(endY) > Math.abs(endX)) && !canScrooll){
getParent().requestDisallowInterceptTouchEvent(false);
resetScroll();
}else{
getParent().requestDisallowInterceptTouchEvent(true);
canScrooll = true;
}
if(canScrooll){
int scroll = currentScroll + endX;
if(scroll < -scrollLimitSize){
scroll = -scrollLimitSize;
}else if(scroll > 0){
scroll = 0;
}
scrollTo(- scroll, 0);
}
break;
case MotionEvent.ACTION_UP:
int divide = scrollLimitSize >> 1;
if (getScrollX() > divide){
scroller.startScroll(getScrollX(), 0, scrollLimitSize - getScrollX(), 0, TIME);
}else{
scroller.startScroll(getScrollX(), 0, - getScrollX(), 0, TIME);
}
invalidate();
currentScroll = -getScrollX();
getParent().requestDisallowInterceptTouchEvent(false);
canScrooll = false;
return !isClick;
default:
break;
}
return true;
}
private void resetScroll(){
scroller.startScroll(getScrollX(), 0, - getScrollX(), 0, TIME);
invalidate();
currentScroll = -getScrollX();
}
@Override
public void computeScroll() {
super.computeScroll();
if(scroller.computeScrollOffset()){
scrollTo(scroller.getCurrX(), scroller.getCurrY());
invalidate();
}
}
}
侧滑比较简单，值得注意的是 在作为Recyclerview 的item布局时， 水平和垂直滑动一次只能触发一个，所以通过canScrooll 变量控制滑动冲突，正好解决了这个问题。
end。
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