ConstraintLayout之Infer Constraints(推斷約束)

在使用 ConstraintLayout 的時候，發現一個異常：

This view is not constrained vertically: at runtime it will jump to the left unless you add a vertical constraint less… (Ctrl+F1)
The layout editor allows you to place widgets anywhere on the canvas, and it records the current position with designtime attributes (such as layout_editor_absoluteX.) These attributes are not applied at runtime, so if you push your layout on a device, the widgets may appear in a different location than shown in the editor. To fix this, make sure a widget has both horizontal and vertical constraints by dragging from the edge connections.

我仔細檢查了約束條件，都是沒有問題的，但是顯示我缺少約束條件，編譯後會將所有的控件堆在左上角，我選擇了無視異常，但是異常沒有無視我，編譯後的效果類似於FarmeLayout沒有添加位置約束一樣的效果，後來查找百度，發現瞭解決方案：

1.切換xml到design試圖下
2.選中ConstraintLayout右鍵選擇Constraint Layout中的Infer Constraints

但是我將AndroidStudio的視圖打開以後，仔細檢查了，卻沒有發現上圖的提示：

最後我仔細檢查了一遍，終於讓我找到了：

解決問題！

參考：

http://blog.csdn.net/u010296640/article/details/72922165