Flutter TextField设置默认值默认值和光标位置

主要通过controller 实现，具体代码如下

1TextField(　　　　　　　　　　//输入键盘类型
2              keyboardType: TextInputType.text,
3              autofocus: true,
4              decoration: InputDecoration(
5                border: OutlineInputBorder(
6                    borderRadius: BorderRadius.circular(30),
7                    borderSide: BorderSide.none),
8              ),
9              onChanged: (value) {
10                this._keyword = value;
11              },
12              controller: TextEditingController.fromValue(TextEditingValue(
13                  text: '${this._keyword == null ? "" : this._keyword}',  //判断keyword是否为空
14                  // 保持光标在最后
15
16                  selection: TextSelection.fromPosition(TextPosition(
17                      affinity: TextAffinity.downstream,
18                      offset: '${this._keyword}'.length)))),
19            ),