如何从ConstraintSet中获取指定方向已连接视图以在指定View前插入新View

安全阿岳

2026-10-7

实现方案

你可以用ConstraintSet提供的getConnection()方法获取指定View对应方向的约束信息，无需额外传入insertAfter参数，修改后的代码如下：

private void insertBefore(int toInsert, int insertBefore) {
    ConstraintSet cs = new ConstraintSet();
    ConstraintLayout root = findViewById(R.id.constraintRoot);
    cs.clone(root);

    // 获取insertBefore原本的顶部约束信息
    ConstraintSet.Connection topConnection = cs.getConnection(insertBefore, ConstraintSet.TOP);
    int oldTargetId = topConnection.target;
    int oldTargetSide = topConnection.targetSide;
    int oldMargin = topConnection.margin;

    // 先断开insertBefore原来的顶部约束
    cs.clear(insertBefore, ConstraintSet.TOP);
    // 把insertBefore的顶部连到待插入View的底部
    cs.connect(insertBefore, ConstraintSet.TOP, toInsert, ConstraintSet.BOTTOM, 0);
    // 待插入View的顶部连到原来insertBefore的顶部目标，沿用原来的margin
    cs.connect(toInsert, ConstraintSet.TOP, oldTargetId, oldTargetSide, oldMargin);

    // 保持两个View的左右约束一致，避免横向错位
    ConstraintSet.Connection leftConnection = cs.getConnection(insertBefore, ConstraintSet.LEFT);
    cs.connect(toInsert, ConstraintSet.LEFT, leftConnection.target, leftConnection.targetSide, leftConnection.margin);
    ConstraintSet.Connection rightConnection = cs.getConnection(insertBefore, ConstraintSet.RIGHT);
    cs.connect(toInsert, ConstraintSet.RIGHT, rightConnection.target, rightConnection.targetSide, rightConnection.margin);

    root.setConstraintSet(cs);
}