67

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：

按钮

我想像这样删除它，但在代码中：

这是顶部删除约束的按钮

所以想要以编程方式实现相同的效果

这是我尝试过的代码：

    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，但结果甚至有所不同，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);
4

4 回答 4

160

我尚未完成您的代码，但以下说明了如何使用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);
于 2017-06-22T13:12:57.983 回答
12

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

假设我们要移除约束布局本身的底部约束，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
于 2020-04-20T09:04:10.410 回答
2

这是j2emanue using答案的 Java 版本ConstraintLayout.LayoutParams，它可以在不指定布局约束的元素的 id 的情况下工作：

final ConstraintLayout constraintLayout = findViewById(R.id.constraintLayout);
final ConstraintLayout.LayoutParams layoutParams = (ConstraintLayout.LayoutParams) constraintLayout.getLayoutParams();
layoutParams.bottomToBottom = ConstraintLayout.LayoutParams.UNSET;
constraintLayout.setLayoutParams(layoutParams);
于 2020-09-08T02:54:35.190 回答
0

如果您在 Kotlin 中使用 viewBinding/dataBinding，现在有一种更简单的方法。

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
                    }
于 2022-02-21T20:27:51.687 回答