第三十一篇-TextInputLayout(增强文本输入)的使用

效果图：

密码使用的是增强文本输入类型，当密码长度小于6或者密码长度大于10的时候就会给出提示。

main.xml

当添加TextInputLayout时，旁边会有一个下载符号，如果点不动，可以右键点击add to design，然后它会加载，加载完毕后，后面那个下载符号就消失了，可以拖动它到相应位置了。

然后可以在MainActivity.java中设置当状态改变时需要进行的操作：

textInputEditText.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {

    }

    @Override
    public void afterTextChanged(Editable s) {
        if(textInputEditText.getText().toString().length()>textInputLayout.getCounterMaxLength()|
                textInputEditText.getText().toString().length()<6){
            textInputLayout.setError("密码长度为6~10位");
        }
        else{
            textInputLayout.setError("");
        }

    }
});

beforeTextChanged是状态改变前，onTextChanged是状态改变中，afterTextChanged是状态改变后，我们一般用最后一个。其中getCounterMaxLength的大小是在main.xml中设置的，我设置的是10.

MainActivity.java

package com.example.aimee.textinputlayouttest;

import android.support.design.widget.TextInputEditText;
import android.support.design.widget.TextInputLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;

public class MainActivity extends AppCompatActivity {
    TextInputLayout textInputLayout;
    TextInputEditText textInputEditText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textInputLayout=findViewById(R.id.textinputlayout1);
        textInputEditText=findViewById(R.id.textinputedit1);
        check();
    }

    private void check(){
        textInputEditText.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                if(textInputEditText.getText().toString().length()>textInputLayout.getCounterMaxLength()|
                        textInputEditText.getText().toString().length()<6){
                    textInputLayout.setError("密码长度为6~10位");
                }
                else{
                    textInputLayout.setError("");
                }

            }
        });
    }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
    android:gravity="center"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="用户名" />

        <EditText
            android:id="@+id/editText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ems="10"
            android:inputType="textPersonName"
            android:text="" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密码" />

        <android.support.design.widget.TextInputLayout
            android:id="@+id/textinputlayout1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:counterMaxLength="10">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/textinputedit1"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="请输入密码"
                android:inputType="textPassword" />
        </android.support.design.widget.TextInputLayout>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="登录" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="取消" />
    </LinearLayout>

</LinearLayout>