ConstraintLayout:以编程方式更改约束

时间:2017-07-23 08:41:02

标签: android android-layout android-view android-constraintlayout

我需要ConstraintSet的帮助。我的目标是在代码中更改视图的约束,但我无法弄清楚如何正确执行此操作。

我有4个TextView和一个ImageView。我需要将ImageView约束设置为其中一个TextView

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,我需要设置ImageView

的约束
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"

等等。

8 个答案:

答案 0 :(得分:100)

  1. 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:

    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);
    
  2. 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:

    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);
    

答案 1 :(得分:35)

假设我们想在运行时更改约束,使button1在单击时与button2对齐:

enter image description here

然后,有了这个布局:

<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()
        }
    }

答案 2 :(得分:6)

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 = otherView.id
        topToTop = otherView.id
        bottomToBottom = otherView.id
        //add other constraints if needed
      }

答案 3 :(得分:4)

在Kotlin中,您可以简单地扩展ConstraintSet类并添加一些方法来利用Kotlin中的dsl并产生更具可读性的代码。 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
}

并像这样使用它

        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
        }

答案 4 :(得分:4)

除了azizbekian's answer外,我还要指出两点:

  1. 如果左/右不起作用,请尝试像这样开始/结束:

float

  1. 如果要删除约束,请使用UNSET标志,如下所示:

params.startToEnd = button2.id

答案 5 :(得分:2)

我知道我的答案已经很晚了,但是我敢肯定,这会帮助很多在这里停留的人。 这篇文章不是我的,但我做了一些更改,也就是说,您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ConstraintSet类。此类包含一些方法,可以执行诸如创建,配置约束并将约束应用于ConstraintLayout实例的任务。另外,可以将ConstraintLayout实例的当前约束复制到ConstraintSet对象中,并用于将相同约束应用于其他布局(带有或不带有修改)。

创建了ConstraintSet实例,就像创建其他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以执行各种任务。 下面的代码配置了一个约束集,在该约束集中,Button视图的左侧连接到EditText视图的右侧,其边距为70dp:

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

将约束应用于布局 配置约束集后,必须先将其应用于ConstraintLayout实例,然后才能生效。通过调用applyTo()方法来应用约束集,并通过对要对其应用设置的布局对象的引用来实现:

set.applyTo(myLayout);

ConstraintSet API可以做更多的事情,设置水平和垂直偏差,水平和垂直居中,操纵链条等等。

真的很不错。

再次,这只是改编。

答案 6 :(得分:0)

@vishakha yeolekar 的解决方案对我不起作用。

要更改约束,我们需要执行以下步骤:

  • 克隆父级布局
  • 清除以前的约束
  • 连接约束
  • 约束应用于父级布局

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ConstraintSet-Click Here的更多信息和方法的链接。

答案 7 :(得分:0)

您还可以使用 TransitionManager 为更改设置动画:

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);
}

使用 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);