ConstraintLayout：以编程方式更改约束

Question

我需要 ConstraintSet 方面的帮助。我的目标是在代码中更改视图的约束，但我不知道如何正确地做到这一点。

我有 4 个 TextView 和一个 ImageView。我需要将 ImageView 约束设置为 TextView 之一。

check_answer4 = (TextView) findViewById(R.id.check_answer4);
check_answer1 = (TextView) findViewById(R.id.check_answer1);
check_answer2 = (TextView) findViewById(R.id.check_answer2);
check_answer3 = (TextView) findViewById(R.id.check_answer3);

correct_answer_icon = (ImageView) findViewById(R.id.correct_answer_icon);

如果第一个答案是正确的，我需要将 ImageView 的约束设置为

app:layout_constraintRight_toRightOf="@+id/check_answer1"
app:layout_constraintTop_toTopOf="@+id/check_answer1"

如果第二个答案是正确的，我需要将 ImageView 的约束设置为

app:layout_constraintRight_toRightOf="@+id/check_answer2"
app:layout_constraintTop_toTopOf="@+id/check_answer2"

以此类推

Answer 1

要将图像视图的约束设置为：

 app:layout_constraintRight_toRightOf="@+id/check_answer1"
 app:layout_constraintTop_toTopOf="@+id/check_answer1"

使用：

 ConstraintLayout constraintLayout = findViewById(R.id.parent_layout);
 ConstraintSet constraintSet = new ConstraintSet();
 constraintSet.clone(constraintLayout);
 constraintSet.connect(R.id.imageView,ConstraintSet.RIGHT,R.id.check_answer1,ConstraintSet.RIGHT,0);
 constraintSet.connect(R.id.imageView,ConstraintSet.TOP,R.id.check_answer1,ConstraintSet.TOP,0);
 constraintSet.applyTo(constraintLayout);

要将图像视图的约束设置为：

 app:layout_constraintRight_toRightOf="@+id/check_answer2"
 app:layout_constraintTop_toTopOf="@+id/check_answer2"

使用：

 ConstraintLayout constraintLayout = findViewById(R.id.parent_layout);
 ConstraintSet constraintSet = new ConstraintSet();
 constraintSet.clone(constraintLayout); 
 constraintSet.connect(R.id.imageView,ConstraintSet.RIGHT,R.id.check_answer2,ConstraintSet.RIGHT,0);      
 constraintSet.connect(R.id.imageView,ConstraintSet.TOP,R.id.check_answer2,ConstraintSet.TOP,0);
 constraintSet.applyTo(constraintLayout);

Answer 2

假设我们想在运行时更改约束，使按钮 1 在单击时与按钮 2 对齐：

然后，有这个布局：

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/root"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">


    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button 1"
        app:layout_constraintTop_toTopOf="@+id/button3"
        app:layout_constraintBottom_toBottomOf="@+id/button3"
        app:layout_constraintStart_toEndOf="@+id/button3"
        android:layout_marginStart="0dp"
        app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginEnd="0dp" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="16dp"
        android:text="Button 2"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        android:layout_marginStart="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginEnd="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginBottom="8dp"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="8dp"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintVertical_bias="0.5" />

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="16dp"
        android:text="Button 3"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        android:layout_marginStart="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        android:layout_marginEnd="8dp"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginBottom="8dp"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintVertical_bias="0.223" />
</android.support.constraint.ConstraintLayout>

我们可以做到以下几点：


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        button1.setOnClickListener {
            val params = button1.layoutParams as ConstraintLayout.LayoutParams
            params.leftToRight = button2.id
            params.topToTop = button2.id
            params.bottomToBottom = button2.id
            button1.requestLayout()
        }
    }

Answer 3

在 Kotlin 中，您可以简单地扩展 ConstraintSet class 并添加一些方法来利用 Kotlin 中的 dsl 并生成更具可读性的代码。像这样

class KotlinConstraintSet : ConstraintSet() {

    companion object {
        inline fun buildConstraintSet(block:KotlinConstraintSet.()->Unit) =
            KotlinConstraintSet().apply(block)
    }
    //add this if you plan on using the margin param in ConstraintSet.connect
    var margin: Int? = null
        get() {
            val result = field
            margin = null //reset it to work with other constraints
            return result
        }

    inline infix fun Unit.and(other: Int) = other // just to join two functions

    inline infix fun Int.topToBottomOf(bottom: Int) =
        margin?.let {
            connect(this, TOP, bottom, BOTTOM, it)
        } ?: connect(this, TOP, bottom, BOTTOM)

    inline fun margin(margin: Int) {
        this.margin = margin
    }

    inline infix fun Int.bottomToBottomOf(bottom: Int) =
        margin?.let {
            connect(this, BOTTOM, bottom, BOTTOM, it)
        } ?: connect(this, BOTTOM, bottom, BOTTOM)

    inline infix fun Int.topToTopOf(top: Int) =
        margin?.let {
            connect(this, TOP, top, TOP, it)
        } ?: connect(this, TOP, top, TOP)

    inline infix fun Int.startToEndOf(end: Int) =
        margin?.let {
            connect(this, START, end, END, it)
        } ?: connect(this, START, end, END)

            ...
    //TODO generate other functions depending on your needs

    infix fun Int.clear(constraint: Constraints) =
        when (constraint) {
            Constraints.TOP -> clear(this, TOP)
            Constraints.BOTTOM -> clear(this, BOTTOM)
            Constraints.END -> clear(this, END)
            Constraints.START -> clear(this, START)
        }

    //inline infix fun clearTopCon
    inline infix fun appliesTo(constraintLayout: ConstraintLayout) =
        applyTo(constraintLayout)

    inline infix fun clones(constraintLayout: ConstraintLayout) =
        clone(constraintLayout)

    inline fun constraint(view: Int, block: Int.() -> Unit) =
        view.apply(block)
}

enum class Constraints {
    TOP, BOTTOM, START, END //you could add other values to use with the clear fun like LEFT
}

然后像这样使用它

        buildConstraintSet {
            this clones yourConstraintLayout
            constraint(R.id.view1) {
                margin(value:Int) and this topToBottomOf R.id.view2
                margin(30) and this bottomToBottomOf ConstraintSet.PARENT_ID
            }
            constraint(R.id.view2) {
                this clear Constraints.BOTTOM
                margin(0) and this topToTopOf R.id.topGuide
            }
            constraint(R.id.view4) {
                this topToTopOf R.id.view2
                this bottomToBottomOf R.id.view3
                this startToEndOf R.id.view2
            }
            //or you could simply do
            R.id.view1 startToEndOf R.view2
            R.id.view1 toptToBottomOf R.view3
            R.id.view3 bottomtToBottomOf R.view2
            R.id.view3 clear Constraints.END

            // and finally call applyTo()
            this appliesTo yourConstraintLayout
        }

Answer 4

我知道我的回答已经很晚了，但我相信它会对路过这里的其他人有很大帮助。这篇文章不是我的，但我做了一些修改，话虽这么说，你应该努力查看完整的文章 here

约束集

在 Java 代码中使用约束集的关键是约束集 class。此 class 包含一系列方法，这些方法允许执行诸如创建、配置和应用约束到 ConstraintLayout 实例等任务。此外，可以将 ConstraintLayout 实例的当前约束复制到 ConstraintSet 对象中，并用于将相同的约束应用于其他布局（修改或不修改）。

ConstraintSet 实例的创建方式与任何其他 Java 对象一样：

ConstraintSet set = new ConstraintSet();

创建约束集后，可以在实例上调用方法来执行各种任务。以下代码配置了一个约束集，其中 Button 视图的左侧连接到 EditText 视图的右侧，边距为 70dp:

set.connect(button1.getId(), ConstraintSet.LEFT, 
        editText1.getId(), ConstraintSet.RIGHT, 70);

对布局应用约束配置约束集后，必须将其应用于 ConstraintLayout 实例才能生效。通过调用 applyTo() 方法应用约束集，传递对要应用设置的布局对象的引用：

set.applyTo(myLayout);

您可以使用 ConstraintSet API、设置水平和垂直偏差、水平和垂直居中、操纵链等更多操作。

读得真好。

再次声明，这只是改编。

Answer 5

除了，我还要指出两点：

如果 left/right 不起作用，请像这样尝试 start/end：

params.startToEnd = button2.id

如果要删除约束，请像这样使用 UNSET 标志：

params.startToEnd = ConstraintLayout.LayoutParams.UNSET

Answer 6

@vishakha yeolekar 的解决方案对我不起作用。

要更改约束，我们需要按照以下步骤操作：

克隆父布局
清除之前的约束
连接约束
对父布局应用约束

解决方案代码（在 Kotlin 中）

val clParent = findViewById<ConstraintLayout>(R.id.parent_layout)
val mConstraintSet = ConstraintSet()
mConstraintSet.clone(clParent)
mConstraintSet.clear(R.id.imageView, ConstraintSet.END)
mConstraintSet.connect(R.id.imageView, ConstraintSet.END, R.id.check_answer, ConstraintSet.END)
mConstraintSet.applyTo(clParent)

这里是 link 以获取 ConstraintSet 的更多信息和方法 - Click Here。

Answer 7

另一种方法是像这样更新视图的布局参数（不请求布局）：

yourView.updateLayoutParams<ConstraintLayout.LayoutParams> {
        startToEnd = targetView.id
        topToTop = targetView.id
        bottomToBottom = targetView.id
        //add other constraints if needed
      }

Answer 8

您还可以使用 TransitionManager 来动画更改：

public static void animateConstraintLayout(ConstraintLayout constraintLayout, ConstraintSet set, long duration) {
    AutoTransition trans = new AutoTransition();
    trans.setDuration(duration);
    trans.setInterpolator(new AccelerateDecelerateInterpolator());

    TransitionManager.beginDelayedTransition(constraintLayout, trans);
    set.applyTo(constraintLayout);
}

用ConstraintSet更新布局后可以这样调用：

ConstraintSet set = new ConstraintSet();
set.clone(constraintLayout);
set.connect(R.id.example, ConstraintSet.BOTTOM, R.id.anotherExample, ConstraintSet.BOTTOM);
set.connect(R.id.example, ConstraintSet.TOP, R.id.anotherExample, ConstraintSet.TOP);

animateConstraintLayout(constraintLayout, set, 500);

ConstraintLayout：以编程方式更改约束

ConstraintLayout: change constraints programmatically

android

android-layout

android-view

android-constraintlayout

约束集

解决方案代码（在 Kotlin 中）