Are createHorizontalChain and createHorizontalChainRtl swapped?

Question

I was trying to create a constraint chain programmatically, using the code bellow.

class Table extends Component {
  constructor (props) {
  super(props);

  this.state = {
    table: this.createTable()
  }

  componentWillReceiveProps(nextProps) {
    this.setState({table: this.createTable()});
  }

  createTable() {
    // function using sizeX, sizeY and bombNumber
  }
}

I have getting the following error:

bombNumber

Then I realized that the implementation of this method is as follow:

updateSize (val, side) {
  this.setState({[side]: val}, function () {
    this.setState({maxBombNumber: this.calculateMaxBombNumber()}, function () {
      if (this.state.maxBombNumber < this.state.bombNumber) {
        this.setState({bombNumber: this.state.maxBombNumber}, function (){
          console.log(this.state);
        });
      }
    });
  });
}

Should I use set.createHorizontalChain( ConstraintSet.PARENT_ID, ConstraintSet.START, ConstraintSet.PARENT_ID, ConstraintSet.END, new int[] {view1.getId(), view2.getId()}, null, ConstraintSet.CHAIN_PACKED ); which seems to work, since 6 and 7 are the values for Caused by: java.lang.IllegalArgumentException: Left to start undefined at android.support.constraint.ConstraintSet.connect(ConstraintSet.java:922) at android.support.constraint.ConstraintSet.createHorizontalChain(ConstraintSet.java:883) at android.support.constraint.ConstraintSet.createHorizontalChain(ConstraintSet.java:850) and public void createHorizontalChain(int leftId, int leftSide, int rightId, int rightSide, int[] chainIds, float[] weights, int style) { this.createHorizontalChain(leftId, leftSide, rightId, rightSide, chainIds, weights, style, 1, 2); } public void createHorizontalChainRtl(int startId, int startSide, int endId, int endSide, int[] chainIds, float[] weights, int style) { this.createHorizontalChain(startId, startSide, endId, endSide, chainIds, weights, style, 6, 7); } meaning this is a bug, or I am doing something wrong here?

Seriously, dealing with createHorizontalChainRtl programmatically has being really challenging.

Answer 1

你应该改用

set.createHorizontalChain(
            ConstraintSet.PARENT_ID, ConstraintSet.RIGHT,
            ConstraintSet.PARENT_ID, ConstraintSet.LEFT,
            new int[] {ITEM_ID_1, ITEM_ID_2},
            null ,
            ConstraintSet.CHAIN_SPREAD);

这将在所有项目之间创建一个链。如果您的项目是在XML中创建的，那么您可能需要清除已应用的ConstrainSet，方法是使用ConstrainSet.Clear(ITEM_ID)获取新的约束集。然后开始新的约束集规则。

如果清除项目的constrainSet，则不要忘记添加

set.constrainWidth(ITEM_ID, ConstraintSet.WRAP_CONTENT);
set.constrainHeight(ITEM_ID, ConstraintSet.WRAP_CONTENT);

最后不要忘记.applyTo

set.applyTo(constraintLayout);

这是一个相当不错的例子，但是这个人过早地将所有项目连接起来，这是不必要的。 HorizontalChain Example

以下是有关chain styles

的详细信息

Here is also a Wiki关于如何在代码中使用constrainlayout。