Android ConstraintLayout:以编程方式更改约束
我需要有关约束集的帮助。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执行 我有4个Android ConstraintLayout:以编程方式更改约束,android,android-layout,android-view,android-constraintlayout,Android,Android Layout,Android View,Android Constraintlayout,我需要有关约束集的帮助。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执行 我有4个TextViews和一个ImageView。我需要将ImageView约束设置为TextViews之一 check_answer4 = (TextView) findViewById(R.id.check_answer4); check_answer1 = (TextView) findViewById(R.id.check_answer1); check_answer2 = (TextView) find
TextView
s和一个ImageView
。我需要将ImageView
约束设置为TextView
s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);
如果第一个答案正确,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"
app:layout_constraintRight_toRightOf="@+id/check_answer2"
app:layout_constraintTop_toTopOf="@+id/check_answer2"
如果第二个答案正确,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"
app:layout_constraintRight_toRightOf="@+id/check_answer2"
app:layout_constraintTop_toTopOf="@+id/check_answer2"
等等
app:layout_constraintRight_toRightOf="@+id/check_answer1"
app:layout_constraintTop_toTopOf="@+id/check_answer1"
app:layout_constraintRight_toRightOf="@+id/check_answer2"
app:layout_constraintTop_toTopOf="@+id/check_answer2"
使用:
app:layout_constraintRight_toRightOf="@+id/check_answer1"
app:layout_constraintTop_toTopOf="@+id/check_answer1"
app:layout_constraintRight_toRightOf="@+id/check_answer2"
app:layout_constraintTop_toTopOf="@+id/check_answer2"
使用:
假设我们希望在运行时更改约束,使button1在单击时与button2对齐: 然后,有这样的布局:
<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>
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并生成更可读的代码。
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
}
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
}
我知道我的答案已经很晚了,但我相信这会对来这里的其他人有很大帮助。 这篇文章不是我写的,但我做了一些修改,也就是说,你应该努力查看整篇文章 约束集 在Java代码中使用约束集的关键是ConstraintSet类。此类包含一系列方法,这些方法允许创建、配置约束以及将约束应用于ConstraintLayout实例等任务。此外,ConstraintLayout实例的当前约束可以复制到ConstraintSet对象中,并用于将相同的约束应用于其他布局(有修改或无修改) ConstraintSet实例的创建与任何其他Java对象一样:
ConstraintSet set = new ConstraintSet();
一旦创建了约束集,就可以在实例上调用方法来执行广泛的任务。
以下代码配置一个约束集,其中按钮视图的左侧连接到EditText视图的右侧,边距为70dp:
set.connect(button1.getId(), ConstraintSet.LEFT,
editText1.getId(), ConstraintSet.RIGHT, 70);
将约束应用于布局
配置约束集后,必须将其应用于ConstraintLayout实例,约束集才会生效。通过调用applyTo()方法应用约束集,并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执行更多操作,设置水平和垂直偏移、水平和垂直居中、操纵链等等
读得真不错
同样,这只是一种改编。此外,让我指出两件事:
params.startToEnd=button2.id
params.startToEnd=ConstraintLayout.LayoutParams.UNSET
@vishakha yeolekar的解决方案对我不起作用
要更改约束,我们需要遵循以下步骤:
- 克隆父布局
- 清除以前的约束
- 连接约束
- 将约束应用于父布局
val clParent=findviewbyd(R.id.parent\u布局)
val mConstraintSet=ConstraintSet()
mConstraintSet.clone(clParent)
mConstraintSet.clear(R.id.imageView,ConstraintSet.END)
mConstraintSet.connect(R.id.imageView,ConstraintSet.END,R.id.check\u answer,ConstraintSet.END)
mConstraintSet.applyTo(clParent)
以下是ConstraintSet-的更多信息和方法的链接。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{
startToEnd=otherView.id
toptoop=otherView.id
bottomToBottom=otherView.id
//如果需要,添加其他约束
}
为此,您必须动态更改约束。@shweta我正是在问这个问题,如何通过友好的方式进行?获取。发布您的答案.constraintSet.clone(constraintLayout);在这一行中,constraintLayout是父布局吗?@Pang.clone(constraintLayout)
这个变量是什么,从哪里获得它?@ReejeshPK@MiXT4PE是的,它是父布局,即constraintLayout constraintLayout=findViewById(R.id.parent\u布局)
@leonheess我认为这应该是一个引用约束布局视图组的变量尝试了10种不同的方法,效果很好。非常感谢。我的朋友,我不明白你的密码。。什么是layoutParams
和val
?这是Java吗?先生,这是kotlin编程语言。Java等价物将是ConstraintLayout.LayoutParams=(ConstraintLayout.LayoutParams)button1.getLayoutParams()代码>我想你忘了写button1.layoutParams=params@sumitsonawane,它是不需要的,因为我们正在变异该实例,然后执行button1.requestLayout()
,然后将检查我们变异的LayoutParams
的实例。@azizbekian,是的,对我来说,最终的解决方案是将requestLayout()
调用替换为setLayoutParams()
,然后它就可以工作了。简单地改变layoutParams
并自己请求布局似乎并不能奏效。
yourView.updateLayoutParams<ConstraintLayout.LayoutParams> {
startToEnd = otherView.id
topToTop = otherView.id
bottomToBottom = otherView.id
//add other constraints if needed
}