1.TextInputLayout是一种嵌套格式，首先将你要输入信息的Views放置在嵌套格式里，每个View分别嵌套

<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">

</android.support.design.widget.TextInputLayout>

2.调整好UI之后，使用各种method来使用

setError(String)，设置error hint

出现error后使用requestFocus()来设置焦点

3.完整的layout如下：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.mazingtec.myapplication.LoginActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginTop="32dp"
        android:text="Login"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <android.support.design.widget.TextInputLayout
        android:id="@+id/ad1"
        android:layout_width="146dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="32dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView">

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="0dp"
        android:layout_marginRight="0dp"
        android:layout_marginTop="60dp"
        android:ems="10"
        android:hint="Email"
        android:inputType="textEmailAddress"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

    </android.support.design.widget.TextInputLayout>

    <android.support.design.widget.TextInputLayout
        android:id="@+id/ad2"
        android:layout_width="146dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="32dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ad1">

        <EditText
            android:id="@+id/editText2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="0dp"
            android:layout_marginRight="0dp"
            android:layout_marginTop="32dp"
            android:ems="10"
            android:hint="Password"
            android:inputType="textPassword"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintHorizontal_bias="0.5" />

</android.support.design.widget.TextInputLayout>

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="32dp"
        android:text="Log in"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ad2" />
</android.support.constraint.ConstraintLayout>

4.完整的代码如下：

 1 package com.mazingtec.myapplication;
 2 
 3 import android.support.v7.app.AppCompatActivity;
 4 import android.os.Bundle;
 5 import android.text.TextUtils;
 6 import android.view.View;
 7 import android.widget.Button;
 8 import android.widget.EditText;
 9 import android.widget.Toast;
10 
11 public class LoginActivity extends AppCompatActivity implements View.OnClickListener{
12 
13     private EditText editText;
14     private EditText editText2;
15     private Button button2;
16 
17     @Override
18     protected void onCreate(Bundle savedInstanceState) {
19         super.onCreate(savedInstanceState);
20         setContentView(R.layout.activity_login);
21 
22         editText = (EditText) findViewById(R.id.editText);
23         editText2 = (EditText) findViewById(R.id.editText2);
24         button2 = (Button) findViewById(R.id.button2);
25 
26         button2.setOnClickListener(this);
27 
28     }
29 
30     @Override
31     public void onClick(View v) {
32         if(v == button2) {
33             onLonin();
34         }
35 
36     }
37 
38     private void onLonin() {
39         String email = editText.getText().toString();
40         String password = editText2.getText().toString();
41 
42         if(TextUtils.isEmpty(email)) {
43             editText.setError("Please enter your email");
44             editText.requestFocus();
45             return;
46         }
47 
48         if(TextUtils.isEmpty(password)) {
49             editText2.setError("Please enter your password");
50             editText2.requestFocus();
51             return;
52         }
53 
54         Toast.makeText(this, "Done!", Toast.LENGTH_LONG).show();
55 
56 
57     }
58 }

TextInputLayout