在ConstraintLayout中以编程方式删除/添加约束

Question

我想根据某些条件以编程方式删除和添加约束.以下是截图:

我想删除它,但在代码中:

所以想要以编程方式实现同​​样的效果

这是我试过的代码:

    if (advertisements.size() > 0) { //my own condition
        ConstraintLayout.LayoutParams layoutParams = (ConstraintLayout.LayoutParams) btnCreateAd.getLayoutParams();
        layoutParams.topToBottom = R.id.imvEmpty; //the imageview that is in center of the view
        btnCreateAd.setLayoutParams(layoutParams);
        recyclerView.setVisibility(View.VISIBLE);
        txvMyAdEmptyText.setVisibility(View.GONE);
        imvEmpty.setVisibility(View.GONE);
        adapter.setList(advertisements);
        adapter.notifyDataSetChanged();
    } else {
        ConstraintLayout.LayoutParams layoutParams = (ConstraintLayout.LayoutParams) btnCreateAd.getLayoutParams();
        layoutParams.topToBottom = -1; //here i am trying to remove top constraint but it doesn't work
        btnCreateAd.setLayoutParams(layoutParams);

        recyclerView.setVisibility(View.GONE);
        txvMyAdEmptyText.setVisibility(View.VISIBLE);
        imvEmpty.setVisibility(View.VISIBLE);
        adapter.setList(new ArrayList<Advertisement>());
    }
    mConstraintView.invalidate(); //this is my constraint view

编辑

我也尝试过使用 ConstraintSet,但结果甚至不同,我的RecyclerView(设置为父视图的边界)正在消失

 ConstraintSet set = new ConstraintSet();
    set.clone(parentView);

    if (advertisements.size() > 0) {

        recyclerView.setVisibility(View.VISIBLE);
        txvMyAdEmptyText.setVisibility(View.GONE);
        imvEmpty.setVisibility(View.GONE);
        adapter.setList(advertisements);
        adapter.notifyDataSetChanged();

    } else {

        set.connect(btnCreateAd.getId(), ConstraintSet.TOP, imvEmpty.getId(), ConstraintSet.BOTTOM, 0);

        recyclerView.setVisibility(View.GONE);
        txvMyAdEmptyText.setVisibility(View.VISIBLE);
        imvEmpty.setVisibility(View.VISIBLE);
        adapter.setList(new ArrayList<Advertisement>());
    }
    set.connect(btnCreateAd.getId(), ConstraintSet.END, ConstraintSet.PARENT_ID, ConstraintSet.END, 0);
    set.connect(btnCreateAd.getId(), ConstraintSet.START, ConstraintSet.PARENT_ID, ConstraintSet.START, 0);
    set.connect(btnCreateAd.getId(), ConstraintSet.BOTTOM, ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM, 0);

    set.applyTo(parentView);

Answer 1

我没有完成您的代码,但以下说明了如何使用中断和约束ConstraintSet.

    ConstraintSet set = new ConstraintSet();
    ConstraintLayout layout;

    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);

Answer 2

如果您在 Kotlin 中使用 viewBinding/dataBinding，现在有一种更简单的方法可以做到这一点。

有一个名为 updateLayoutParams 的扩展函数，import androidx.core.view.updateLayoutParams如下所示使用它

    binding.yourView.updateLayoutParams<ConstraintLayout.LayoutParams> {
                        this.startToEnd = ConstraintLayout.LayoutParams.UNSET
                      this.startToStart = ConstraintLayout.LayoutParams.PARENT_ID
                    }

Answer 3

另一种方法是使用ConstraintLayout.LayoutParams.UNSET。这种方式不使用ConstraintSet.clear.

假设我们要移除constraintLayout本身的底部约束但可以是任何视图：

val containerParams = cl_container.layoutParams as ConstraintLayout.LayoutParams
containerParams.bottomToBottom = ConstraintLayout.LayoutParams.UNSET
cl_container.layoutParams = containerParams