動態調整 ConstraintLayout
===
* 範例

<TextView
    android:id="@+id/title"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"/>

<ImageView
    android:id="@+id/image"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@id/title" />

* 實作範例

in `xml`:
`app:layout_constraintTop_toBottomOf=”@id/title”`，意義同下方;

in code progamming:

ConnectConstraint(R.id.image, ConstraintSet.Top, R.id.title, ConstraintSet.BOTTOM)

ConstraintSet set = new ConstraintSet();
ConstraintLayout layout;

// 注意!! 
// 這裡的 R.id.layout 指的是整個佈局檔的最上層的根節點, 且應為 ConstraintLayout
layout = (ConstraintLayout) findViewById(R.id.layout);
set.clone(layout);

// The following breaks the connection.
set.clear(R.id.bottomText, ConstraintSet.TOP);

// Comment out line above and uncomment line below to make the connection.
// set.connect(R.id.bottomText, ConstraintSet.TOP, R.id.imageView, ConstraintSet.BOTTOM, 0);
set.applyTo(layout);

## Ref.
[](https://medium.com/geekculture/programatically-update-view-constraints-in-constraint-layout-f4eb1b6dfc38)
[Removing/Adding constraint programmatically in ConstraintLayout](https://stackoverflow.com/questions/44685816/removing-adding-constraint-programmatically-in-constraintlayout/44700437)

###### tags: `實作相關`