在Android Studio中,有时无法使用ConstraintLayout的set方法来设置以编程方式添加的视图的约束条件。这通常是因为它们未被正确地添加到ConstraintLayout中。
解决这个问题的一种方法是在将视图添加到ConstraintLayout中之前,将其Constraints设置为null。然后再通过setConstraints方法将其添加到ConstraintLayout中。
以下是一个示例代码片段,展示如何编程设置ConstrainLayout中视图的约束条件:
// Create the ConstraintSet
ConstraintSet constraintSet = new ConstraintSet();
// Create the view programmatically
Button button = new Button(this);
button.setText("Programmatic Button");
// Add the view to the ConstraintLayout
ConstraintLayout constraintLayout = (ConstraintLayout) findViewById(R.id.constraint_layout);
constraintLayout.addView(button);
// Set the constraints to null before adding them to the ConstraintSet
button.setId(View.generateViewId());
ConstraintLayout.LayoutParams layoutParams = new ConstraintLayout.LayoutParams(ConstraintLayout.LayoutParams.WRAP_CONTENT,
ConstraintLayout.LayoutParams.WRAP_CONTENT);
button.setLayoutParams(layoutParams);
button.setVisibility(View.VISIBLE);
// Apply the constraints to the view
constraintSet.clone(constraintLayout);
constraintSet.connect(button.getId(), ConstraintSet.LEFT, R.id.activity_main_layout, ConstraintSet.LEFT, 0);
constraintSet.connect(button.getId(), ConstraintSet.TOP, R.id.activity_main_layout, ConstraintSet.TOP, 0);
constraintSet.applyTo(constraintLayout);
这里的代码段将在ConstraintLayout中添加一个新的按钮,并将其左侧和顶部的边缘设置为与ConstraintLayout的边缘对齐。