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自定义横向滑动的 ViewGroup,效果类似系统控件[HorizontalScrollView]
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public class HorizontalView extends ViewGroup { | |
private static final int DEFAULT_DP = 20; | |
int defaultSize; | |
private int touchSlop; | |
private float downInterceptX; | |
private float downInterceptY; | |
private int tapTimeout; | |
private Scroller mScroller; | |
private long elapsedRealtime; | |
private int goodSize; | |
public HorizontalView(Context context) { | |
super(context); | |
init(context); | |
} | |
public HorizontalView(Context context, AttributeSet attrs) { | |
super(context, attrs); | |
init(context); | |
} | |
public HorizontalView(Context context, AttributeSet attrs, int defStyleAttr) { | |
super(context, attrs, defStyleAttr); | |
init(context); | |
} | |
public HorizontalView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { | |
super(context, attrs, defStyleAttr, defStyleRes); | |
init(context); | |
} | |
private void init(Context context) { | |
defaultSize = (int) ViewUtils.dp2px(context, DEFAULT_DP); | |
LogUtils.e("default size ========%s", defaultSize); | |
setWillNotDraw(false); | |
ViewConfiguration configuration = ViewConfiguration.get(context); | |
touchSlop = configuration.getScaledTouchSlop(); | |
tapTimeout = ViewConfiguration.getTapTimeout(); | |
mScroller = new Scroller(context); | |
} | |
@Override | |
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { | |
LogUtils.w(ViewUtils.logMeasureSpec(widthMeasureSpec, "1-w")); | |
LogUtils.w(ViewUtils.logMeasureSpec(heightMeasureSpec, "1-h")); | |
super.onMeasure(widthMeasureSpec, heightMeasureSpec); | |
LogUtils.i(ViewUtils.logMeasureSpec(widthMeasureSpec, "2-w")); | |
LogUtils.i(ViewUtils.logMeasureSpec(heightMeasureSpec, "2-h")); | |
int wMode = MeasureSpec.getMode(widthMeasureSpec); | |
int wSize = MeasureSpec.getSize(widthMeasureSpec); | |
int hMode = MeasureSpec.getMode(heightMeasureSpec); | |
int hSize = MeasureSpec.getSize(heightMeasureSpec); | |
this.goodSize = wSize; | |
int childCount = getChildCount(); | |
if (childCount == 0) { | |
LogUtils.e("no need to set wh, use super."); | |
return; | |
} | |
// measureChildren(widthMeasureSpec, heightMeasureSpec); // 必须要调用 | |
int w = 0, h = defaultSize; | |
for (int i = 0; i < childCount; ++i) { | |
View child = getChildAt(i); | |
if (child == null || child.getVisibility() == GONE) { | |
continue; | |
} | |
measureChildWithMargins(child, | |
0, widthMeasureSpec, | |
0, heightMeasureSpec); | |
int measuredWidth = child.getMeasuredWidth(); | |
int measuredHeight = child.getMeasuredHeight(); | |
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); | |
LogUtils.i("index=%s,wh=(%s,%s), lp:[%s,%s]", i, | |
measuredWidth, measuredHeight, | |
lp.leftMargin, lp.rightMargin); | |
h = Math.max(h, measuredHeight + lp.topMargin + lp.bottomMargin); | |
w += measuredWidth + lp.leftMargin + lp.rightMargin; | |
} | |
w += getPaddingStart() + getPaddingEnd(); // 支持自身的 padding,不加会挡住 children | |
h += getPaddingTop() + getPaddingBottom(); | |
// w = Math.min(w, wSize); // 此时的 wSize 为 match_parent具体数值的大小 | |
// 保证 w 不会超过 parent 预期大小 | |
LogUtils.e("计算前的 ow,oh=(%s,%s),#,计算后的 wh(%s,%s)", wSize, hSize, w, h); | |
if (wMode == MeasureSpec.EXACTLY && hMode == MeasureSpec.EXACTLY) { | |
// LogUtils.e("no need to set wh, use super."); | |
LogUtils.e("m1"); | |
setMeasuredDimension(w > wSize ? w : wSize, h > hSize ? h : hSize); | |
} else if (wMode == MeasureSpec.EXACTLY) { | |
LogUtils.e("m2"); | |
setMeasuredDimension(wSize, h); | |
} else if (hMode == MeasureSpec.EXACTLY) { | |
LogUtils.e("m3"); | |
setMeasuredDimension(w, hSize); | |
} else { | |
LogUtils.e("m4"); | |
setMeasuredDimension(w, h); | |
} | |
} | |
@Override | |
protected void onLayout(boolean changed, int l, int t, int r, int b) { | |
LogUtils.i("- -onLayout(%s,%s,%s,%s)", l, t, r, b); | |
l += getPaddingStart(); | |
r -= getPaddingEnd(); | |
t += getPaddingTop(); | |
b -= getPaddingBottom(); | |
int childCount = getChildCount(); | |
LogUtils.e("childCount = %s", childCount); | |
for (int i = 0; i < childCount; ++i) { | |
View child = getChildAt(i); | |
if (child == null || child.getVisibility() == GONE) { | |
continue; | |
} | |
int measuredWidth = child.getMeasuredWidth(); | |
int measuredHeight = child.getMeasuredHeight(); | |
MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); | |
int w = measuredWidth + lp.leftMargin + lp.rightMargin; | |
l += lp.leftMargin; | |
t += lp.topMargin; | |
LogUtils.d("layout child:"); | |
LogUtils.d("index=%s,#,l,t,r,b (%s,%s,%s,%s)", | |
i, | |
l, t, | |
l + measuredWidth, t + measuredWidth); | |
child.layout(l, t, l + measuredWidth, t + measuredHeight); | |
// for next child | |
l += measuredWidth + lp.rightMargin; | |
t -= lp.topMargin; // 下一个不能沿用上一个的 marginTop, 因为是横向排列,不是总纵向 | |
// t += measuredHeight + lp.bottomMargin; | |
} | |
} | |
@Override | |
protected void onSizeChanged(int w, int h, int oldw, int oldh) { | |
super.onSizeChanged(w, h, oldw, oldh); | |
LogUtils.e("old(%s,%s), now(%s,%s)", oldw, oldh, w, h); | |
} | |
@Override | |
protected LayoutParams generateDefaultLayoutParams() { | |
LogUtils.e("generateDefaultLayoutParams"); | |
return new MarginLayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); | |
} | |
@Override | |
protected LayoutParams generateLayoutParams(LayoutParams p) { | |
LogUtils.e("generateLayoutParams p"); | |
return new MarginLayoutParams(p); | |
} | |
@Override | |
public LayoutParams generateLayoutParams(AttributeSet attrs) { | |
return new MarginLayoutParams(getContext(), attrs); | |
} | |
@Override | |
public boolean onInterceptTouchEvent(MotionEvent ev) { | |
boolean intercept = false; | |
int actionMasked = ev.getActionMasked(); | |
float x = ev.getX(); | |
float y = ev.getY(); | |
switch (actionMasked) { | |
case MotionEvent.ACTION_DOWN: | |
downInterceptX = x; | |
downInterceptY = y; | |
break; | |
case MotionEvent.ACTION_MOVE: | |
if (Math.abs(x - downInterceptX) > Math.abs(y - downInterceptY) | |
&& Math.abs(x - downInterceptX) > touchSlop) { | |
intercept = true; | |
} | |
break; | |
case MotionEvent.ACTION_UP: | |
break; | |
case MotionEvent.ACTION_CANCEL: | |
break; | |
} | |
return intercept || super.onInterceptTouchEvent(ev); | |
} | |
@Override | |
public boolean onTouchEvent(MotionEvent event) { | |
float x = event.getX(); | |
float y = event.getY(); | |
switch (event.getActionMasked()) { | |
case MotionEvent.ACTION_DOWN: | |
elapsedRealtime = SystemClock.elapsedRealtime(); | |
break; | |
case MotionEvent.ACTION_MOVE: | |
float diffX = x - downInterceptX; | |
float diffY = y - downInterceptY; | |
scrollBy((int) -diffX, 0); | |
// 由于 move 会被多次调用 | |
downInterceptX = x; | |
downInterceptY = y; | |
break; | |
case MotionEvent.ACTION_UP: | |
long realtime = SystemClock.elapsedRealtime(); | |
if (Math.abs(y - downInterceptY) < touchSlop | |
&& Math.abs(x - downInterceptX) < touchSlop | |
&& realtime - elapsedRealtime < tapTimeout) { | |
LogUtils.e("click me...."); | |
performClick(); | |
} | |
break; | |
case MotionEvent.ACTION_CANCEL: | |
break; | |
} | |
return true; | |
} | |
@Override | |
public boolean performClick() { | |
return super.performClick(); | |
} | |
@Override | |
public void computeScroll() { | |
// 没用上,没处理 ACTION_UP | |
super.computeScroll(); | |
if (mScroller.computeScrollOffset()) { | |
scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); | |
postInvalidate(); | |
} | |
} | |
@Override | |
public void scrollTo(int x, int y) { | |
// 重写 scrollTo 之后,不让其滑动超出边界 | |
LogUtils.v("scrollTo(%s,%s)", x, y); | |
if (x > getWidth() - goodSize) { | |
LogUtils.v("getWidth(), goodSize=%s,%s", getWidth(), goodSize); | |
x = getWidth() - goodSize; | |
} | |
if (x < 0) { | |
x = 0; | |
} | |
if (x != getScrollX()) { | |
super.scrollTo(x, y); | |
} | |
} | |
} | |
/* | |
* 1. | |
* <FrameLayout fill,fill> | |
* <Self wrap,wrap> | |
* // --> AT_MOST, AT_MOST | |
* </Self> | |
* </FrameLayout> | |
* 2. | |
* <ScrollView> | |
* <Self> | |
* // --> AT_MOST, UNSPECIFIED | |
* </Self> | |
* </ScrollView> | |
*/ |
Author
pythoncat1024
commented
Nov 4, 2019
- 重写 generateLayoutParams 三个方法,让 child 支持 margin 属性
- 重写 onMeasure , 自己的宽度是 children 宽度总和
- 重写 onLayout , 自己的高度是 children 的最大值
- 重写 onIntercept, 是横向滑动就拦截
- 重写 onTouch, move 的时候,通过 scrollBy 进行滑动
- 重写 scrollTo, 不让其滑动超过自身的左右最大边界
使用如下:
<com.view.weigets.HorizontalView
android:padding="100dp"
android:id="@+id/horizontal_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@color/colorAccent">
<Button
android:layout_marginStart="19dp"
android:textSize="18sp"
android:text="@string/app_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:layout_marginTop="18dp"
android:textSize="18sp"
android:text="@string/app_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:textSize="18sp"
android:text="@string/app_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:textSize="18sp"
android:text="@string/app_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</com.view.weigets.HorizontalView>
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