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link管理  ›  动态调整ConstaintLayout元素位置_constraintlayout动态改变里面控件位置
transform android开发 const margin
https://blog.csdn.net/lihenair/article/details/110276398
威武的苹果
3 月前

最近一个需求需要动态添加删除 ConstraintLayout 里的元素，一时不知道如何处理。虽然 ConstraintLayout 确实减少了层级，提升了绘制效率，但对于动态增删却一直没有尝试过。借着这个需求也好好调研了下 ConstraintLayout 的一些相关属性。

按照以往的经验，增删view应该也跟 RelativityLayout 或者 LinearLayout 一样，直接添加就行了。不过在查阅了开发文档和Stack Overflow之后，发现并不是这么简单。这里有个核心的类 ConstraintSet ，控制了元素的位置。相当于原来 RelativityLayout 里的 addRule 方法，但确实另外一个类来处理这些。

需求如下：

点击 button_addtop 时添加一个textview在 image 之下 button_addtop 之上。
点击 button_addbottom 时添加一个textview在 button_addbottom 之下。 

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="@color/colorAccent">
    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/dice_1"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>
    <Button
        android:id="@+id/button_addtop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="addtop"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@id/image"/>
    <Button
        android:id="@+id/button_addbottom"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="addbottom"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@id/button_addtop"/>
</androidx.constraintlayout.widget.ConstraintLayout>

代码如下：
 

override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
): View? {
    val root : ConstraintLayout = inflater.inflate(R.layout.fragment_fourth, container, false) as ConstraintLayout
    root.findViewById<Button>(R.id.button_addtop).setOnClickListener(object : View.OnClickListener {
        override fun onClick(v: View?) {
            textView = TextView(context)
            textView.text = "Naruto"
            textView.id = View.generateViewId()
            textView.background = ColorDrawable(resources.getColor(R.color.colorPrimaryDark, null))
            root.addView(textView)
            val set = ConstraintSet()
            set.clone(root)
            set.connect(textView.id, ConstraintSet.TOP, R.id.image, ConstraintSet.BOTTOM, 500)
            set.connect(textView.id, ConstraintSet.LEFT, ConstraintSet.PARENT_ID, ConstraintSet.LEFT, 200)
            set.connect(textView.id, ConstraintSet.BOTTOM, R.id.button_addtop, ConstraintSet.TOP, 200)
            set.applyTo(root)
            val setaddtop = ConstraintSet()
            setaddtop.clone(root)
            setaddtop.connect(R.id.button_addtop, ConstraintSet.TOP, textView.id, ConstraintSet.BOTTOM)
            setaddtop.applyTo(root)
    root.findViewById<Button>(R.id.button_addbottom).setOnClickListener(object : View.OnClickListener {
        override fun onClick(v: View?) {
            textView = TextView(context)
            textView.text = "Kagawa"
            textView.id = View.generateViewId()
            textView.background = ColorDrawable(resources.getColor(R.color.colorPrimaryDark, null))
            root.addView(textView)
            val set = ConstraintSet()
            set.clone(root)
            set.connect(textView.id, ConstraintSet.TOP, R.id.button_addbottom, ConstraintSet.BOTTOM)
            set.applyTo(root)
    return root

Constraint是ConstraintSet的内部静态类，包括75个属性，是个工具类。这些属性都是ConstraintLayout在布局时设置的xml设置项。
 clone方法复制根布局的ConstraintSet值，将所有view的Constraints.LayoutParams都拷贝到ConstraintSet的mConstraints对象里，这是一个HashMap。




    

 

public void clone(ConstraintLayout constraintLayout) {
	// 获取当前布局的子View数量
    int count = constraintLayout.getChildCount();
    // 清空当前ConstraintSet的mConstraints
    this.mConstraints.clear();
	// 循环拷贝当前布局的子view param到mConstraints中
    for(int i = 0; i < count; ++i) {
        View view = constraintLayout.getChildAt(i);
        LayoutParams param = (LayoutParams)view.getLayoutParams();
        int id = view.getId();
        if (id == -1) {
            throw new RuntimeException("All children of ConstraintLayout must have ids to use ConstraintSet");
        if (!this.mConstraints.containsKey(id)) {
            this.mConstraints.put(id, new ConstraintSet.Constraint());
        ConstraintSet.Constraint constraint = (ConstraintSet.Constraint)this.mConstraints.get(id);
        constraint.fillFrom(id, param);
        constraint.visibility = view.getVisibility();
        if (VERSION.SDK_INT >= 17) {
            constraint.alpha = view.getAlpha();
            constraint.rotation = view.getRotation();
            constraint.rotationX = view.getRotationX();
            constraint.rotationY = view.getRotationY();
            constraint.scaleX = view.getScaleX();
            constraint.scaleY = view.getScaleY();
            float pivotX = view.getPivotX();
            float pivotY = view.getPivotY();
            if ((double)pivotX != 0.0D || (double)pivotY != 0.0D) {
                constraint.transformPivotX = pivotX;
                constraint.transformPivotY = pivotY;
            constraint.translationX = view.getTranslationX();
            constraint.translationY = view.getTranslationY();
            if (VERSION.SDK_INT >= 21) {
                constraint.translationZ = view.getTranslationZ();
                if (constraint.applyElevation) {
                    constraint.elevation = view.getElevation();
        if (view instanceof Barrier) {
            Barrier barrier = (Barrier)view;
            constraint.mBarrierAllowsGoneWidgets = barrier.allowsGoneWidget();
            constraint.mReferenceIds = barrier.getReferencedIds();
            constraint.mBarrierDirection = barrier.getType();

connect方法则根据不同的属性对应的整型值将需要修改的属性进行赋值。
 public void connect(int startID, int startSide, int endID, int endSide)
 public void connect(int startID, int startSide, int endID, int endSide, int margin)
 以带margin的方法为例：
 
 public void connect(int startID, int startSide, int endID, int endSide, int margin) {
    // 查找View.getId对应的限制是否存在，不存在则创建一个value
    if (!mConstraints.containsKey(startID)) {
        mConstraints.put(startID, new Constraint());
    // 找到对应的值
    Constraint constraint = mConstraints.get(startID);
    switch (startSide) {
        case LEFT: // 设置LEFT侧属性，endID是对应的约束布局对象
            if (endSide == LEFT) {
                constraint.layout.leftToLeft = endID;
                constraint.layout.leftToRight = Layout.UNSET;
            } else if (endSide == RIGHT) {
                constraint.layout.leftToRight = endID;
                constraint.layout.leftToLeft = Layout.UNSET;
            } else {
                throw new IllegalArgumentException("Left to " + sideToString(endSide) + " undefined");
            // 设置距left依赖的margin
            constraint.layout.leftMargin = margin;
            break;
        case RIGHT: // 设置RIGHT侧属性，endID是对应的约束布局对象
            if (endSide == LEFT) {
                constraint.layout.rightToLeft = endID;
                constraint.layout.rightToRight = Layout.UNSET;
            } else if (endSide == RIGHT) {
                constraint.layout.rightToRight = endID;
                constraint.layout.rightToLeft = Layout.UNSET;
            } else {
                throw new IllegalArgumentException("right to " + sideToString(endSide) + " undefined");
            // 设置距right依赖的margin
            constraint.layout.rightMargin = margin;
            break;
        case TOP: // 设置TOP侧属性，endID是对应的约束布局对象
            if (endSide == TOP) {
                constraint.layout.topToTop = endID;
                constraint.layout.topToBottom = Layout.UNSET;
                constraint.layout.baselineToBaseline = Layout.UNSET;
            } else if (endSide == BOTTOM) {
                constraint.layout.topToBottom = endID;
                constraint.layout.topToTop = Layout.UNSET;
                constraint.layout.baselineToBaseline = Layout.UNSET;
            } else {
                throw new IllegalArgumentException("right to " + sideToString(endSide) + " undefined");
            // 设置距top依赖的margin
            constraint.layout.topMargin = margin;
            break;
        case BOTTOM: // 设置BOTTOM侧属性，endID是对应的约束布局对象
            if (endSide == BOTTOM) {
                constraint.layout.bottomToBottom = endID;
                constraint.layout.bottomToTop = Layout.UNSET;
                constraint.layout.baselineToBaseline = Layout.UNSET;
            } else if (endSide == TOP) {
                constraint.layout.bottomToTop = endID;
                constraint.layout.bottomToBottom = Layout.UNSET;
                constraint.layout.baselineToBaseline = Layout.UNSET;
            } else {
                throw new IllegalArgumentException("right to " + sideToString(endSide) + " undefined");
            // 设置距bottom依赖的margin
            constraint.layout.bottomMargin = margin;
            break;
        case BASELINE: // 设置BASELINE属性，endID是对应的约束布局对象
            if (endSide == BASELINE) {
                constraint.layout.baselineToBaseline = endID;
                constraint.layout.bottomToBottom = Layout.UNSET;
                constraint.layout.bottomToTop = Layout.UNSET;
                constraint.layout.topToTop = Layout.UNSET;
                constraint.layout.topToBottom = Layout.UNSET;
            } else {
                throw new IllegalArgumentException("right to " + sideToString(endSide) + " undefined");
            break;
        case START: // 设置START侧属性，endID是对应的约束布局对象
            if (endSide == START) {
                constraint.layout.startToStart = endID;
                constraint.layout.startToEnd = Layout.UNSET;
            } else if (endSide == END) {
                constraint.layout.startToEnd = endID;
                constraint.layout.startToStart = Layout.UNSET;
            } else {
                throw new IllegalArgumentException("right to " + sideToString(endSide) + " undefined");
            // 设置距start依赖的margin
            constraint.layout.startMargin = margin;
            break;
        case END: // 设置END侧属性，endID是对应的约束布局对象
            if (endSide == END) {
                constraint.layout.endToEnd = endID;
                constraint.layout.endToStart = Layout.UNSET;
            } else if (endSide == START) {
                constraint.layout.endToStart = endID;
                constraint.layout.endToEnd = Layout.UNSET;
            } else {
                throw new IllegalArgumentException("right to " + sideToString(endSide) + " undefined");
            // 设置距end依赖的margin
            constraint.layout.endMargin = margin;
            break;
        default:
            throw new IllegalArgumentException(
                    sideToString(startSide) + " to " + sideToString(endSide) + " unknown");

applyto方法将属性设置给布局




    

 

public void applyTo(ConstraintLayout constraintLayout) {
    this.applyToInternal(constraintLayout);
    constraintLayout.setConstraintSet((ConstraintSet)null);

实际干活的是applyToInternal。




    

 

void applyToInternal(ConstraintLayout constraintLayout, boolean applyPostLayout) {
    int count = constraintLayout.getChildCount();
    HashSet<Integer> used = new HashSet<Integer>(mConstraints.keySet());
    for (int i = 0; i < count; i++) {
        View view = constraintLayout.getChildAt(i);
        int id = view.getId();
        if (!mConstraints.containsKey(id)) {
            Log.w(TAG, "id unknown " + Debug.getName(view));
            continue;
        if (mForceId && id == -1) {
            throw new RuntimeException("All children of ConstraintLayout must have ids to use ConstraintSet");
        if (id == -1) {
            continue;
        if (mConstraints.containsKey(id)) {
            used.remove(id);
            Constraint constraint = mConstraints.get(id);
            if (view instanceof Barrier) {
                constraint.layout.mHelperType = BARRIER_TYPE;
            if (constraint.layout.mHelperType != UNSET) {
                switch (constraint.layout.mHelperType) {
                    case BARRIER_TYPE:
                        Barrier barrier = (Barrier) view;
                        barrier.setId(id);
                        barrier.setType(constraint.layout.mBarrierDirection);
                        barrier.setMargin(constraint.layout.mBarrierMargin);
                        barrier.setAllowsGoneWidget(constraint.layout.mBarrierAllowsGoneWidgets);
                        if (constraint.layout.mReferenceIds != null) {
                            barrier.setReferencedIds(constraint.layout.mReferenceIds);
                        } else if (constraint.layout.mReferenceIdString != null) {
                            constraint.layout.mReferenceIds = convertReferenceString(barrier,
                                    constraint.layout.mReferenceIdString);
                            barrier.setReferencedIds(constraint.layout.mReferenceIds);
                        break;
            ConstraintLayout.LayoutParams param = (ConstraintLayout.LayoutParams) view
                    .getLayoutParams();
            param.validate();
            constraint.applyTo(param);
            if (applyPostLayout) {
                ConstraintAttribute.setAttributes(view, constraint.mCustomConstraints);
            view.setLayoutParams(param);
            if (constraint.propertySet.mVisibilityMode == VISIBILITY_MODE_NORMAL) {
                view.setVisibility(constraint.propertySet.visibility);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
                view.setAlpha(constraint.propertySet.alpha);
                view.setRotation(constraint.transform.rotation);
                view.setRotationX(constraint.transform.rotationX);
                view.setRotationY(constraint.transform.rotationY);
                view.setScaleX(constraint.transform.scaleX);
                view.setScaleY(constraint.transform.scaleY);
                if (constraint.transform.transformPivotTarget != UNSET) {
                    View layout = (View) view.getParent();
                    View center = layout.findViewById(constraint.transform.transformPivotTarget);
                    if (center != null) {
                        float cy = (center.getTop() + center.getBottom()) / 2.0f;
                        float cx = (center.getLeft() + center.getRight()) / 2.0f;
                        if (view.getRight() - view.getLeft() > 0 && view.getBottom() - view.getTop() > 0) {
                            float px = (cx - view.getLeft());
                            float py = (cy - view.getTop());
                            view.setPivotX(px);
                            view.setPivotY(py);
                } else {
                    if (!Float.isNaN(constraint.transform.transformPivotX)) {
                        view.setPivotX(constraint.transform.transformPivotX);
                    if (!Float.isNaN(constraint.transform.transformPivotY)) {
                        view.setPivotY(constraint.transform.transformPivotY);
                view.setTranslationX(constraint.transform.translationX);
                view.setTranslationY(constraint.transform.translationY);
                if (Build.VERSION.SDK_INT >= VERSION_CODES.LOLLIPOP) {
                    view.setTranslationZ(constraint.transform.translationZ);
                    if (constraint.transform.applyElevation) {
                        view.setElevation(constraint.transform.elevation);
        } else {
            Log.v(TAG, "WARNING NO CONSTRAINTS for view " + id);
    for (Integer id : used) {
        Constraint constraint = mConstraints.get(id);
        if (constraint.layout.mHelperType != UNSET) {
            switch (constraint.layout.mHelperType) {
                case BARRIER_TYPE:
                    Barrier barrier = new Barrier(constraintLayout.getContext());
                    barrier.setId(id);
                    if (constraint.layout.mReferenceIds != null) {
                        barrier.setReferencedIds(constraint.layout.mReferenceIds);
                    } else if (constraint.layout.mReferenceIdString != null) {
                        constraint.layout.mReferenceIds = convertReferenceString(barrier,
                                constraint.layout.mReferenceIdString);
                        barrier.setReferencedIds(constraint.layout.mReferenceIds);
                    barrier.setType(constraint.layout.mBarrierDirection);
                    barrier.setMargin(constraint.layout.mBarrierMargin);
                    ConstraintLayout.LayoutParams param = constraintLayout
                            .generateDefaultLayoutParams();
                    barrier.validateParams();
                    constraint.applyTo(param);
                    constraintLayout.addView(barrier, param);
                    break;
        if (constraint.layout.mIsGuideline) {
            Guideline g = new Guideline(constraintLayout.getContext());
            g.setId(id);
            ConstraintLayout.LayoutParams param = constraintLayout.generateDefaultLayoutParams();
            constraint.applyTo(param);
            constraintLayout.addView(g, param);

实际上是把所有子view的param再赋值给对应的view，并刷新布局。
 

https://www.zoftino.com/adding-views-&-constraints-to-android-constraint-layout-programmatically
 

https://stackoverflow.com/questions/45263159/constraintlayout-change-constraints-programmatically

                    背景最近一个需求需要动态添加删除ConstraintLayout里的元素，一时不知道如何处理。虽然ConstraintLayout确实减少了层级，提升了绘制效率，但对于动态增删却一直没有尝试过。借着这个需求也好好调研了下ConstraintLayout的一些相关属性。按照以往的经验，增删view应该也跟RelativityLayout或者LinearLayout一样，直接添加就行了。不过在查阅了开发文档和Stack Overflow之后，发现并不是这么简单。这里有个核心的类ConstraintSet，控
				
动态设置ConstraintLayout约束
以前一直是在布局里直接设置ConstraintLayout的约束，前几天遇到了一个有点特殊的需求，需要动态设置布局，xml布局使用的ConstraintLayout，所以就立马恶补动态设置ConstraintLayout约束的知识，总结如下。
获取要设置目标控件的父布局。
val constraintLayoutRoot = getView<ConstraintLayout>(R.id.constraint_dynamics_root)
				
* 使用场景：设置布局的时候，想通过ConstraintLayout实现滑块与文字同步移动
* 思路：ConstraintLayout在xml布局中有layout_constraintvertical_bias设置项能否找到一个功能类来完成？
* ConstraintLaout控件引入后可以看到 constraintLayout.setConstraintSet(ConstraintSet set);
* 关键操作是：ConstraintSet constraintSet.setVerticalBias(.

				
如果父View是ConstraintLayout约束布局，当修改某个view时候，直接创建ConstraintLayout.LayoutParams会有问题,没办法直接满足需求。
所有使用ConstraintSet绝对没错
具体使用步骤
ConstraintSet set= new ConstraintSet();
//获取一新的ConstraintLayout
//mConstra...

RelativeLayout.Layoutparams params = (RelativeLayout.LayoutParams)view1.getLayoutParams();
params.addRule(RelativeLayout.LEFT_OF...

一、使用方式:
Android studio 2.2以上 并添加依赖
compile ‘com.android.support.constraint:constraint-layout:1.0.1’
本人用的AS3.0 Pre,不需要添加依赖库,Kotlin 默认就是ConstraintLayout布局.(感觉这东西有点像Masonry啊,写习惯了Masonry 这个也很溜
				
ConstrainLayout是一款布局View，再Design库中，现已被大家广泛接受并使用。ConstrainLayout的布局采用的方式和其他都不同，他的对其方式是类似RelativeLayout，但是和RelativeLayout有明显的区别。
在布局渲染的时候，ConstrainLayout的子View是通过在一个容器中找到自己的位置，通过位置和对其方式来固定，所以在布局优化中，尝尝被提起到。

FrameLayout.LayoutParams lytp = new FrameLayout.LayoutParams(80,LayoutParams.WRAP_CONTENT);
lytp .gravity = Gravity.CENTER;
btn.setLayoutParams(lytp);
Relat...
Barrier 也是辅助线，onDraw 和onMearsure方法也没有实现。但是和Gudline 不同，他是一条可以变化的线
Gudline 有start end 或者percent 来固定位置
Barrier 这条辅助线就很有意思啦。
他可以让你的布局充满动态变化
拿一个场景举例
平时我们如果做登录。多语言的时候
        android:layout_width="match_parent"
        android:layout_height="160dp"
        android:background="@drawable/fullscreen_bg_gradient">
				
Android基础之布局ConstraintLayout Google I/O 2016 上发布了 ConstraintLayout，据说很强大，那就一探究竟吧！
gradle配置
 
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