View篇:玩一下自定义ViewGroup
自定义ViewGroup可不像自定义View那么简单
今日聚焦:
1.自定义ViewGroup中花样布局子View
2.移动View用layout、translation、TranslationAnimation、ViewPropertyAnimator、scrollTo、scrollBy有什么区别?
3.ViewGroup里怎么给孩子加动画
4.惯性移动? 也许你可以了解一下
效果 1 | 效果 2 |
---|---|
一、前置知识:
1.生命函数
这是我曾经测试画出的一张图,描述了ViewGroup+两个孩子的生命函数调用情况
在这补充一点,ViewGroup在没有背景时不会走onDraw方法,但可以走dispatchDraw
原因在于View对onDraw的控制时做了限定:[if (!dirtyOpaque) onDraw(canvas)]
你可以使用onDraw,在之前设个透明色即可:setBackgroundColor(0x00000000);
2.View与Activity之间
貌似一直没有对Activity与View的生命周期一起做过测试
测试之后发现View加载完成之后(onFinishInflate
)并未立即回调测量、布局、绘制
而是在onResume
之后View才会回调onAttachedToWindow-->onMeasure-->onSizeChanged-->onLayout-->onDraw
这一点确实让我挺惊讶,以前竟然没注意,现在理清了,通畅很多
2019-02-19 16:50:29.998 : onCreate --------------
2019-02-19 16:50:29.992 : 构造函数: 0
2019-02-19 16:50:29.996 : onFinishInflate: 0
2019-02-19 16:50:33.001 : onStart: ...................
2019-02-19 16:50:33.006 : onResume: ...................
2019-02-19 16:50:33.050 : onAttachedToWindow:
2019-02-19 16:50:33.207 : onMeasure: 0
2019-02-19 16:50:33.243 : onMeasure: 0
2019-02-19 16:50:33.354 : onSizeChanged: 1948
2019-02-19 16:50:33.358 : onLayout: 1948
2019-02-19 16:50:33.395 : onDraw: 1948
二、自定义ViewGroup (排兵布阵
)
经测试发现注意点:
[1].必须onMeasure中测量孩子的尺寸,否则无法显示
[2].必须onLayout中布局孩子的位置,否则无法显示
[3].在onLayout中孩子不能用view.getHeight()获取尺寸(因为为0),只能用view.getMeasuredHeight
1.最简形式的ViewGroup
这里使用适配器模式,跟ListView一个套路,其实是非常简单,看箭头所指
这里暂时不对ViewGroup进行测量,先填满。对子View用自带的测量方法measureChildren
public class FlowerLayout extends ViewGroup {
private int mRadius;
private static final String TAG = "FlowerLayout";
--->private ListAdapter mAdapter;
--->public void setAdapter(ListAdapter adapter) {
mAdapter = adapter;
}
public FlowerLayout(Context context) {
this(context, null);
}
public FlowerLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public FlowerLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(attrs);
setBackgroundColor(0x55D3E8FD);
}
private void init(AttributeSet attrs) {
}
private void formFlower() {
for (int i = 0; i < mAdapter.getCount(); i++) {
---> View petal = mAdapter.getView(i, null, this);
addView(petal);//填入花瓣
}
}
@Override
protected void onAttachedToWindow() {
Log.e(TAG, "onAttachedToWindow: ");
---> if (mAdapter != null) {
formFlower();
}
super.onAttachedToWindow();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
measureChildren(widthMeasureSpec, heightMeasureSpec);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
//TODO 布局子view
}
}
---->[Activity中使用]----------------
setContentView(R.layout.activity_flower);
FlowerLayout flowerLayout = findViewById(R.id.id_fl);
ArrayList<Petal> petals = new ArrayList<>();
petals.add(new Petal(R.mipmap.icon_1, "icon_1"));
petals.add(new Petal(R.mipmap.icon_2, "icon_2"));
petals.add(new Petal(R.mipmap.icon_3, "icon_3"));
petals.add(new Petal(R.mipmap.icon_4, "icon_4"));
petals.add(new Petal(R.mipmap.icon_5, "icon_5"));
petals.add(new Petal(R.mipmap.icon_6, "icon_6"));
petals.add(new Petal(R.mipmap.icon_7, "icon_7"));
petals.add(new Petal(R.mipmap.icon_8, "icon_8"));
petals.add(new Petal(R.mipmap.icon_9, "icon_9"));
petals.add(new Petal(R.mipmap.icon_10, "icon_10"));
flowerLayout.setAdapter(new FlowerAdapter(petals));
---->[FlowerAdapter视图适配器]---------------------------
public class FlowerAdapter extends BaseAdapter {
private List<Petal> mPetals;
public FlowerAdapter(List<Petal> petals) {
mPetals = petals;
}
@Override
public int getCount() {
return mPetals.size();
}
@Override
public Object getItem(int position) {
return mPetals.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View view = inflater.inflate(R.layout.flower_item, parent, false);
ImageView iv = view.findViewById(R.id.id_pic);
iv.setImageResource(mPetals.get(position).resId);
TextView tv = view.findViewById(R.id.id_info);
tv.setText(mPetals.get(position).info);
return view;
}
}
2.布局子view
这里关键在排布这里给张图先:子View布局的左上右下
---->[FlowerLayout#onLayout]----------------
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View childView = getChildAt(i);
int childW = childView.getMeasuredWidth();
int childH = childView.getMeasuredHeight();
int topPos = (int) (childH * i*0.5f);
int leftPos = 0;
childView.layout(leftPos, topPos, leftPos + childW, topPos + childH);
}
|-- 现在只要修改topPos和leftPos就可以改变子View布局
3.放置成圆形
圆形布局.png---->[FlowerLayout#onLayout]----------------
int count = mAdapter.getCount();
for (int i = 0; i < count; i++) {
View childView = getChildAt(i);
int childW = childView.getMeasuredWidth();
int childH = childView.getMeasuredHeight();
mRadius = (getWidth()-childW) / 2;
float posX = childW / 2 + mRadius - mRadius * cos(i * 360.f / count);
float posY = childH / 2 + mRadius - mRadius * sin(i * 360.f / count);
int leftPos = (int) (posX - childW / 2);
int topPos = (int) (posY - childH / 2);
childView.layout(leftPos, topPos, leftPos + childW, topPos + childH);
}
private float cos(float θ) {
return (float) Math.cos(θ / 180 * Math.PI);
}
private float sin(float θ) {
return (float) Math.sin(θ / 180 * Math.PI);
}
4.添加点击事件
这就比较容易了,一个监听搞定
//在形成View之后就添加点击事件
private void formFlower() {
for (int i = 0; i < mAdapter.getCount(); i++) {
View petal = mAdapter.getView(i, null, this);
int position = i;
if (mOnItemClickListener != null) {
petal.setOnClickListener(v -> {
ObjectAnimator.ofFloat(v, "ScaleX", 1f, 0.8f,1f).setDuration(200).start();
ObjectAnimator.ofFloat(v, "ScaleY", 1f, 0.8f,1f).setDuration(200).start();
mOnItemClickListener.onClick(v, this, position);
});
}
addView(petal);//填入花瓣
}
//----------------------------条目点击监听-------------------
public interface OnItemClickListener {
void onClick(View v, ViewGroup viewGroup, int position);
}
private OnItemClickListener mOnItemClickListener;
public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
mOnItemClickListener = onItemClickListener;
}
5.数组点阵定位
这突然让我想到一个好玩的东西,那就是点阵控位。
点阵控位可以使用二维数组,也可以使用字符串,也可以使用像素点。
具体的可以详见我的这篇:这里就放一张核心的分析图:我们这里不画圆,而是取点位
[图片上传失败...(image-d7dba5-1551090212219)]
/**
* 用来显示点阵的二维数组
*/
public static final int[][] digit_test = new int[][]
{
{0, 0, 0, 1, 0, 0, 0},
{0, 0, 1, 0, 1, 0, 0},
{0, 0, 1, 0, 1, 0, 0},
{0, 1, 0, 1, 0, 1, 0},
{0, 1, 0, 0, 0, 1, 0},
{0, 1, 0, 0, 0, 1, 0},
{0, 0, 0, 0, 0, 0, 0},
{0, 0, 0, 0, 0, 0, 0},
};
/**
* 点位解析器
* @param w 单体宽
* @param h 单体高
* @return 解析成的点位数组
*/
private List<Point> renderDigit(int w, int h) {
List<Point> points = new ArrayList<>();
for (int i = 0; i < digit_test.length; i++) {
for (int j = 0; j < digit_test[j].length; j++) {//一行一行遍历,遇到1就画
if (digit_test[i][j] == 1) {
int rX = (j * 2 + 1) * (w + 1);//第(i,j)个点圆心横坐标
int rY = (i * 2 + 1) * (h + 1);//第(i,j)个点圆心纵坐标
points.add(new Point(rX, rY));
}
}
}
return points;
}
---->[onLayout使用点位]-------------------
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
List<Point> points = renderDigit(
getChildAt(0).getMeasuredWidth() / 2,
getChildAt(0).getMeasuredHeight() / 2
);
int count = mAdapter.getCount();
for (int i = 0; i < count; i++) {
View childView = getChildAt(i);
int childW = childView.getMeasuredWidth();
int childH = childView.getMeasuredHeight();
mRadius = (getWidth() - childW) / 2;
int leftPos = (int) (points.get(i).x - childW / 2);
int topPos = (int) (points.get(i).y - childH / 2);
childView.layout(leftPos, topPos, leftPos + childW, topPos + childH);
}
}
ok了,只要把1放在你想要的位置,子View就在那里,
不过简单一点的还好说,要是爱心...来看神技:
5.位图点阵定位
用黑白(就相当于上面1,0)来标识点位,再根据Bitmap的像素进行
Bitmap内存杀手? 7*7像素的Bitmap也就九牛一毛...
就是下面的小不点,你可以下载玩玩。有PS,你也可以用ps自己戳点
我在这里呢....
像素点位.png
mBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.heart);
/**
* 点位解析器
*
* @param bitmap bitmap
* @param w 单体宽
* @param h 单体高
* @return 解析成的点位数组
*/
public static List<Point> renderBitmap(Bitmap bitmap, int w, int h) {
List<Point> points = new ArrayList<>();
for (int i = 0; i < bitmap.getWidth(); i++) {
for (int j = 0; j < bitmap.getHeight(); j++) {
int pixel = bitmap.getPixel(i, j);
if (pixel != -1) {//此处过滤掉白颜色
int rX = (i * 2 + 1) * (w + 1);//第(i,j)个点圆心横坐标
int rY = (j * 2 + 1) * (h + 1);//第(i,j)个点圆心纵坐标
points.add(new Point(rX, rY));
}
}
}
return points;
}
到这里排兵布阵就结束了,相信对onLayout已经能玩的6了吧,接下来上阵杀敌。
二.移动测试篇
既然是测试,就一切从简,直切问题本身,这里新建了一个Activity
并且打开了手机自带的布局便界显示,这样更能说明问题所在
1.布局
布局界面.png自定义:TestViewGroup+TestView纯原生,不加防腐剂
为了说明问题,这里的TestViewGroup加了边距20dp
<?xml version="1.0" encoding="utf-8"?>
<com.toly1994.analyzer.widget.TestViewGroup
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fl"
android:layout_marginTop="20dp"
android:layout_marginStart="20dp"
android:layout_width="300dp"
android:layout_height="200dp"
android:background="#5597FFFA">
<com.toly1994.analyzer.widget.TestView
android:id="@+id/view"
android:layout_width="200dp"
android:layout_height="50dp"
android:background="#23F627"/>
</com.toly1994.analyzer.widget.TestViewGroup>
2.代码实现
/**
* 作者:张风捷特烈<br/>
* 时间:2019/2/20/020:10:30<br/>
* 邮箱:1981462002@qq.com<br/>
* 说明:测试ViewGroup
*/
public class TestViewGroup extends ViewGroup {
public TestViewGroup(Context context) {
super(context);
}
public TestViewGroup(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
measureChildren(widthMeasureSpec, heightMeasureSpec);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
View child = getChildAt(0);
child.layout(0, 0, child.getMeasuredWidth(), child.getMeasuredHeight());
}
}
/**
* 作者:张风捷特烈<br/>
* 时间:2019/2/20/020:10:30<br/>
* 邮箱:1981462002@qq.com<br/>
* 说明:测试View
*/
public class TestView extends View {
public TestView(Context context) {
super(context);
}
public TestView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
}
3.移动:layout与translation
这样对比应该非常明显:layout真的把布局移动了,translation只是离家出走而已
layout----- | translation |
---|---|
layout.gif | translation.gif |
点击事件在绿色上 | 点击事件在绿色上 |
---->[TestViewGroup#onTouchEvent]-------------
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
int x = (int) event.getX();
int y = (int) event.getY();
// useLayout(mChild, x, y);
useTranslation(mChild, x, y);
}
return super.onTouchEvent(event);
}
private void useLayout(View view, int x, int y) {
view.layout(x, y,
x + view.getMeasuredWidth(), y + view.getMeasuredHeight());
//以下四行等价上一行
// mChild.setLeft(x);
// mChild.setTop(y);
// mChild.setRight(x + mChild.getMeasuredWidth());
// mChild.setBottom(y + mChild.getMeasuredHeight());
}
private void useTranslation(View view, int x, int y) {
view.setTranslationX(x);
view.setTranslationY(y);
}
4 : 移动动画和属性动画
移动动画都是从家里开始,属性动画移动从当前位置,但是家还在那里!
也就是传说中的属性动画也并无法改变View的布局位置
TranslationAnimation | ViewPropertyAnimator |
---|---|
TranslateAnimation.gif | ViewPropertyAnimator.gif |
点击事件在家里 | 点击事件在绿色上 |
private void useTranslationAnimation(View view, int x, int y) {
TranslateAnimation translateAnimation = new TranslateAnimation(0, x, 0, y);
translateAnimation.setDuration(500);
translateAnimation.setFillAfter(true);
view.startAnimation(translateAnimation);
}
private void useViewPropertyAnimator(View view, int x, int y) {
view.animate().translationX(x).translationY(y).setDuration(500).start();
//下两句效果同上
// ObjectAnimator.ofFloat(view, "translationX", x).setDuration(500).start();
// ObjectAnimator.ofFloat(view, "translationY", y).setDuration(500).start();
}
5:哥就像让View搬家动画怎么办?
对Layout进行属性动画.gif很简单:ValueAnimator呗,在刷新时对layout进行更新
由于有四个setXXX方法,这里,简单一点,使用ObjectAnimator
private void useLayoutAnimate(View view, int x, int y) {
//下两句效果同上
ObjectAnimator.ofInt(view, "Left", x).setDuration(500).start();
ObjectAnimator.ofInt(view, "Top", y).setDuration(500).start();
ObjectAnimator.ofInt(view, "Right", x+view.getMeasuredWidth()).setDuration(500).start();
ObjectAnimator.ofInt(view, "Bottom", y + view.getMeasuredHeight()).setDuration(500).start();
}
6:scrollTo和scrollBy
可以说这两个方法和上面的不是一辈的人,应用场景有很大区别
这两个方法是移动一个View内部的所有
子View,调用方并非
子View
至于To和By的区别,也是老生常谈,看图体悟吧...
scrollTo | scrollBy |
---|---|
---->[onTouchEvent]---------------
useScrollTo(-x, -y);
useScrollBy(-x, -y);
--------------------------------------------
private void useScrollTo(int x, int y) {
scrollTo(x, y);
}
private void useScrollBy(int x, int y) {
scrollBy(x, y);
}
Ok ,基础知识就到这里,言归正传:
三、添加动画
下面这幅图应该不难吧,如果做不出来...下面的就当看风景吧...
静态 | 动态 |
---|---|
1.首先把排成圆的方法封装一下
/**
* @param start 第一个排成圆的View索引
* @param dθ 旋转角度
*/
private void layoutCircle(int start, float dθ) {
int count = getChildCount();
for (int i = start; i < count; i++) {
View childView = getChildAt(i);
int childW = childView.getMeasuredWidth();
int childH = childView.getMeasuredHeight();
int r = (getWidth() - childW) / 2;
float posX = childW / 2 + r - r * cos(i * 360.f / (count - 1) + dθ);
float posY = childH / 2 + r - r * sin(i * 360.f / (count - 1) + dθ);
int leftPos = (int) (posX - childW / 2);
int topPos = (int) (posY - childH / 2);
childView.layout(leftPos, topPos, leftPos + childW, topPos + childH);
}
}
2.ValueAnimator走起
在点击的时候触发mAnimator.start()即可
mAnimator = ValueAnimator.ofInt(0, 360);
mAnimator.setDuration(3000);
mAnimator.addUpdateListener(a -> {
int deg = (int) a.getAnimatedValue();
layoutCircle(1, deg);
});
3.位置交换的功能
这里实现和中心的交换,并且加入移动动画
无动画 | 有动画 |
---|---|
---->[维护成员变量]-------------
private int centerId = 0;//默认中心点
/**
* 交换两个View的位置
* @param positionMe 点击者
* @param positionHe 目标
*/
private void swap(int positionMe, int positionHe) {
View me = getChildAt(positionMe);
View he = getChildAt(positionHe);
int TempMeLeft = me.getLeft();
int TempMeTop = me.getTop();
int TempMeRight = me.getRight();
int TempMeBottom = me.getBottom();
me.layout(he.getLeft(), he.getTop(), he.getRight(), he.getBottom());
he.layout(TempMeLeft, TempMeTop, TempMeRight, TempMeBottom);
centerId = positionMe;
}
|--然后只需要在需要的时候触发即可:
swap(position, centerId);
动画,刚才貌似写过了,直接拿来用
/**
* 交换两个View的位置
* @param positionMe 点击者
* @param positionHe 目标
*/
private void swapWithAnim(int positionMe, int positionHe) {
View me = getChildAt(positionMe);
View he = getChildAt(positionHe);
int TempMeLeft = me.getLeft();
int TempMeTop = me.getTop();
useLayoutAnimate(me, he.getLeft(), he.getTop());
useLayoutAnimate(he, TempMeLeft,TempMeTop);
centerId = positionMe;
}
private void useLayoutAnimate(View view, int x, int y) {
ObjectAnimator.ofInt(view, "Left", x).setDuration(500).start();
ObjectAnimator.ofInt(view, "Top", y).setDuration(500).start();
ObjectAnimator.ofInt(view, "Right", x + view.getMeasuredWidth()).setDuration(500).start();
ObjectAnimator.ofInt(view, "Bottom", y + view.getMeasuredHeight()).setDuration(500).start();
}
既然可以动画,那么则么玩都可以,比如旋转和放大
动画就不展开了,详情可见:Android 动画 Animator 家族使用指南
旋转 | 放大 |
---|---|
三、你觉得无聊,玩点6的
1.神技之一:VelocityTracker
这个类估计听过的人不多,翻译出来是
速度追踪器
,作为一个好用的类,在此拎出来讲一讲
它的作用是获取你滑动的x,y的速度x 左负,y上负
---->[FlowerLayout#init]---------------
private void init(AttributeSet attrs) {
...
velocityTracker = VelocityTracker.obtain();//1.VelocityTracker的创建
}
---->[FlowerLayout#onTouchEvent]---------------
@Override
public boolean onTouchEvent(MotionEvent event) {
View centerView = getChildAt(0);
velocityTracker.addMovement(event);//2.VelocityTracker与event结合
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
...
break;
case MotionEvent.ACTION_MOVE:
velocityTracker.computeCurrentVelocity(1000);//3.计算速度
//4.获取值
Log.e(TAG, "X velocity: " + velocityTracker.getXVelocity()+
"--Y velocity: " + velocityTracker.getYVelocity());
break;
case MotionEvent.ACTION_UP:
...
break;
}
return true;
}
|--注意第5点:在适当的地方取消和回收
velocityTracker.clear();//取消
velocityTracker.recycle();//回收
|---我们比较在意的是计算速度的方法,1000是搞嘛的?
/**
* Equivalent to invoking {@link #computeCurrentVelocity(int, float)} with a maximum
* velocity of Float.MAX_VALUE.
* 也就是说这里的第三参是Float的最大值,表示这个速度足以超光速
* @see #computeCurrentVelocity(int, float)
*/
public void computeCurrentVelocity(int units) {
nativeComputeCurrentVelocity(mPtr, units, Float.MAX_VALUE);
}
/**
* @param units The units you would like the velocity in. A value of 1
* provides pixels per millisecond, 1000 provides pixels per second, etc.
你想要的单位是速度。值1表示像素/毫秒,1000表示像素/秒,等等。
* @param maxVelocity The maximum velocity that can be computed by this method.
* This value must be declared in the same unit as the units parameter. This value
* must be positive. 该方法可以计算的最大值
*/
public void computeCurrentVelocity(int units, float maxVelocity) {
nativeComputeCurrentVelocity(mPtr, units, maxVelocity);
}
|-- native方法就不挖了
2.有了速度能干嘛?
惯性.gif
注
接下来的这部分源于陈小缘的Android实现圆弧滑动效果之ArcSlidingHelper篇
我认真研究了一下,并融入了本ViewGroup,他封装的非常好,我拆了一下截取了和惯性相关的部分
不懂的可以去深度一下,我就不卖弄唇舌了,GitHub在:ArcSlidingHelper
---->[FlowerLayout#onLayout]--------------------
private void initRotate() {
int width = getWidth();
int height = getHeight();
mPivotX = width/2;
mPivotY = height/2;
mVelocityTracker = VelocityTracker.obtain();
mScrollAvailabilityRatio = .3F;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
View centerView = getChildAt(0);
float x, y;
x = event.getRawX();
y = event.getRawY();
mVelocityTracker.addMovement(event);
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mAnimator.start();
abortAnimation();
centerView.layout(x, y,
x + centerView.getMeasuredWidth(), y + centerView.getMeasuredHeight());
Log.e("EVENT", "onTouchEvent: " + x + "------" + y);
break;
case MotionEvent.ACTION_MOVE:
handleActionMove(x, y);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_OUTSIDE:
mVelocityTracker.computeCurrentVelocity(1000);
mScroller.fling(0, 0,
(int) mVelocityTracker.getXVelocity(),
(int) mVelocityTracker.getYVelocity(),
Integer.MIN_VALUE, Integer.MAX_VALUE,
Integer.MIN_VALUE, Integer.MAX_VALUE);
startFling();
break;
}
mStartX = x;
mStartY = y;
return true;
}
//------------------------惯性旋转----------------------------
private Scroller mScroller = new Scroller(getContext());
private int mPivotX, mPivotY;
private float mStartX, mStartY;
private float mLastScrollOffset;
private float mScrollAvailabilityRatio;
private boolean isClockwiseScrolling;
private boolean isShouldBeGetY;
private boolean isRecycled;
private VelocityTracker mVelocityTracker;
private Handler mHandler = new Handler(msg -> {
computeInertialSliding();
return false;
});
/**
* 处理惯性滚动
*/
private void computeInertialSliding() {
checkIsRecycled();
if (mScroller.computeScrollOffset()) {
float y = ((isShouldBeGetY ? mScroller.getCurrY() : mScroller.getCurrX()) * mScrollAvailabilityRatio);
if (mLastScrollOffset != 0) {
float offset = fixAngle(Math.abs(y - mLastScrollOffset));
float deg = isClockwiseScrolling ? offset : -offset;
setRotation(getRotation() + deg);
}
mLastScrollOffset = y;
startFling();
} else if (mScroller.isFinished()) {
mLastScrollOffset = 0;
}
}
/**
* 计算滑动的角度
*/
private void handleActionMove(float x, float y) {
float l, t, r, b;
if (mStartX > x) {
r = mStartX;
l = x;
} else {
r = x;
l = mStartX;
}
if (mStartY > y) {
b = mStartY;
t = y;
} else {
b = y;
t = mStartY;
}
float pA1 = Math.abs(mStartX - mPivotX);
float pA2 = Math.abs(mStartY - mPivotY);
float pB1 = Math.abs(x - mPivotX);
float pB2 = Math.abs(y - mPivotY);
float hypotenuse = (float) Math.sqrt(Math.pow(r - l, 2) + Math.pow(b - t, 2));
float lineA = (float) Math.sqrt(Math.pow(pA1, 2) + Math.pow(pA2, 2));
float lineB = (float) Math.sqrt(Math.pow(pB1, 2) + Math.pow(pB2, 2));
if (hypotenuse > 0 && lineA > 0 && lineB > 0) {
float angle = fixAngle((float) Math.toDegrees(Math.acos((Math.pow(lineA, 2) + Math.pow(lineB, 2) - Math.pow(hypotenuse, 2)) / (2 * lineA * lineB))));
float deg = (isClockwiseScrolling = isClockwise(x, y)) ? angle : -angle;
setRotation(getRotation() + deg);
}
}
/**
* 打断动画
*/
public void abortAnimation() {
checkIsRecycled();
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
}
/**
* 释放资源
*/
public void release() {
checkIsRecycled();
mScroller = null;
mVelocityTracker.recycle();
mVelocityTracker = null;
isRecycled = true;
}
/**
* 检测手指是否顺时针滑动
*
* @param x 当前手指的x坐标
* @param y 当前手指的y坐标
* @return 是否顺时针
*/
private boolean isClockwise(float x, float y) {
return (isShouldBeGetY = Math.abs(y - mStartY) > Math.abs(x - mStartX)) ?
x < mPivotX != y > mStartY : y < mPivotY == x > mStartX;
}
/**
* 开始惯性滚动
*/
private void startFling() {
mHandler.sendEmptyMessage(0);
}
/**
* 调整角度,使其在360之间
*
* @param rotation 当前角度
* @return 调整后的角度
*/
private float fixAngle(float rotation) {
float angle = 360F;
if (rotation < 0) {
rotation += angle;
}
if (rotation > angle) {
rotation = rotation % angle;
}
return rotation;
}
/**
* 检查资源释放已经释放
*/
private void checkIsRecycled() {
if (isRecycled) {
throw new IllegalStateException(" is recycled!");
}
}
OK,今天就到这里
后记:捷文规范
1.本文成长记录及勘误表
项目源码 | 日期 | 附录 |
---|---|---|
V0.1--github | 2018-2-20 | 无 |
发布名:
View篇:玩一下自定义ViewGroup
捷文链接:https://juejin.im/post/5c6d198b5188256269118a15
2.更多关于我
笔名 | 微信 | |
---|---|---|
张风捷特烈 | 1981462002 | zdl1994328 |
我的github:https://github.com/toly1994328
我的简书:https://www.jianshu.com/u/e4e52c116681
我的掘金:https://juejin.im/user/5b42c0656fb9a04fe727eb37
个人网站:http://www.toly1994.com
3.声明
icon_wx_200.png1----本文由张风捷特烈原创,转载请注明
2----欢迎广大编程爱好者共同交流
3----个人能力有限,如有不正之处欢迎大家批评指证,必定虚心改正
4----看到这里,我在此感谢你的喜欢与支持