如何以编程方式修改约束布局？

Question

我得到如下视图：

 <org.rayanmehr.atlas.shared.customview.CustomTextView
    android:id="@+id/tvDownVoteCount"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="6dp"
    app:layout_constraintVertical_bias="0"
    app:layout_constraintTop_toBottomOf="@+id/anchorHelper"
    app:layout_constraintLeft_toRightOf="@+id/tvDownVoteIcon"
    app:layout_constraintBottom_toBottomOf="@+id/imgComment"
    />

如何以编程方式修改 app:layout_constraintVertical_bias 或任何其他约束属性的值，而无需在我的 activity 中重新设置整个属性集？

Answer 1

免责声明：我没有使用过这个特定的功能。这只是我对如何尝试做的解释。

我认为你需要的是ConstraintSet. After obtaining it, you could modify it and apply it again. This is a relevant example from this article。

override fun onCreate(savedInstanceState: Bundle?) {
    ...
    val constraintSet1 = ConstraintSet()
    constraintSet1.clone(constraintLayout)
    val constraintSet2 = ConstraintSet()
    constraintSet2.clone(constraintLayout)
    constraintSet2.centerVertically(R.id.image, 0)

    var changed = false
    findViewById(R.id.button).setOnClickListener {
        TransitionManager.beginDelayedTransition(constraintLayout)
        val constraint = if (changed) constraintSet1 else constraintSet2
        constraint.applyTo(constraintLayout)
        changed = !changed
    }
}

Answer 2

我刚刚在 here 中找到了答案，您可以使用 ConstraintSet 实现如下所示：

ConstraintSet constraintSet = new ConstraintSet();
constraintSet.clone(context, R.id.activity_constraint);
//for example lets change the vertical bias of tvDownVoteIcon
float biasedValue = 0.2f;
constraintSet.setVerticalBias(R.id.tvDownVoteIcon, biasedValue);
//you can do any other modification and then apply
constraintSet.applyTo( (ConstraintLayout) findViewById(R.id.activity_constraint));

Answer 3

这是我所做的（不需要 ConstraintSet，我们可以直接在约束本身上工作）：

ConstraintLayout.LayoutParams params = (ConstraintLayout.LayoutParams) myView.getLayoutParams();
params.horizontalBias = 0.2f; // here is one modification for example. modify anything else you want :)
myView.setLayoutParams(params); // request the view to use the new modified params

当我在它下面有一个 SeekBar 和一个 TextView（左+右对齐）时，它就像一个魅力，我想更新 TextView 位置在 SeekBar 的光标下，所以我必须更新 SeekBar 的 OnSeekBarChangeListener

的水平偏移参数

Answer 4

如果您使用的是 Kotlin 并且您有 androidx-core-ktx 库，您可以简单地执行以下操作：

someView.updateLayoutParams<ConstraintLayout.LayoutParams> { horizontalBias = 0.5f }

如何以编程方式修改约束布局？

how to MODIFY a constraint layout programmatically?

android

android-constraintlayout