React Native: this.setState is not a function

Do not use bind inside a render. bind is a rather expensive operation and should only happen once. you have two options:

either bind the function in the constructor:

this._handleTextChange = this._handleTextChange.bind(this);

or use arrow function:

onSubmitEditing={(e) => this._handleTextChange(e)} />

Edit

Apparently arrow functions inside render is also a bad practice (Thx to Adam Terlson in the comments and answer below). You can read eslint docs which states:

A bind call or arrow function in a JSX prop will create a brand new function on every single render. This is bad for performance, as it will result in the garbage collector being invoked way more than is necessary.

Using arrow functions is obviously not as bad as using bind, but nevertheless should be avoided.