java - 以编程方式设置百分比宽度 constraintlayout Android

Question

对于 Android 中的约束布局 v1.1.x，我们可以将高度和宽度设置为百分比。同样，需要以编程方式在 Android 中将 View 宽度和高度设置为百分比:例如，这段代码是用 xml 编写的，用于一些约束布局:

<!-- the widget will take 40% of the available space -->
    app:layout_constraintWidth_default="percent"
    app:layout_constraintWidth_percent="0.4"

运行时它的 java 代码是什么？

Answer 1

您需要使用 ConstraintSet - Reference

This class allows you to define programmatically a set of constraints to be used with ConstraintLayout. It lets you create and save constraints, and apply them to an existing ConstraintLayout. ConstraintsSet can be created in various ways:

mConstraintLayout = (ConstraintLayout) findViewById(R.id.myconstraint_layout)

ConstraintSet set = new ConstraintSet();

// Add constrains - Here R.id.myconstraint_layout is the Id of your constraint layout
set.constrainPercentHeight(R.id.myconstraint_layout, 0.4);
set.constrainPercentWidth(R.id.myconstraint_layout, 0.4);

// Apply the changes - mConstraintLayout is reference to the desired view
set.applyTo(mConstraintLayout); 

你可以在这个集合上调用那些高宽百分比的方法

• constrainPercentHeight(int viewId, float percent)
• constrainPercentWidth(int viewId, float percent)

然后像这样将这些约束应用于您的约束布局

set.applyTo(mConstraintLayout);