实现意见反馈剩余字数先看下效果图

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.ranlegeran.feedbackdemo.MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="50dip"
        android:background="#FFFFFF">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="意见反馈"
        android:textSize="18sp"
        android:textColor="#000000"/>
    </RelativeLayout>

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

   <EditText
       android:id="@+id/et_content"
       android:layout_width="match_parent"
       android:layout_height="130dp"
       android:layout_marginTop="15dp"
       android:layout_marginLeft="10dp"
       android:layout_marginRight="10dp"
       android:padding="8dp"
       android:gravity="left|top"
       android:hint="说点什么吧~我们会做得更好~"
       android:textSize="15sp"
       android:maxLength="200"
       android:background="@drawable/shape_et_bg"/>

   <TextView
       android:id="@+id/text_count"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_marginTop="15dp"
       android:layout_marginRight="10dp"
       android:layout_gravity="right"
       android:text="0/200"/>
    </LinearLayout>

    <Button
        android:id="@+id/btn_submit"
        android:layout_width="match_parent"
        android:layout_height="45dp"
        android:layout_marginTop="35dp"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        android:text="提交"
        android:textColor="#FFFFFF"
        android:textSize="16sp"
        android:background="@drawable/shape_btn_bg"/>

</LinearLayout>

用到的资源文件：shape_et_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" >

    <solid android:color="#FFFFFF" />

    <stroke
        android:width="1px"
        android:color="#FFFFFF" />

    <padding
        android:bottom="1dp"
        android:left="1dp"
        android:right="1dp"
        android:top="1dp" />

</shape>

shape_btn_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">

    <solid android:color="#00CBAB"/>

    <corners android:radius="10.0px"/>

    <padding
        android:top="10dp"
        android:bottom="10dp"
        android:left="10dp"
        android:right="10dp"/>

</shape>

MainActivity部分

package com.ranlegeran.feedbackdemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private static final int MAX_COUNT = 200;
    private EditText mEtContent = null;
    private TextView mTextCount = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mEtContent = (EditText) findViewById(R.id.et_content);
        mTextCount = (TextView) findViewById(R.id.text_count);
        mEtContent.addTextChangedListener(new TextWatcher() { //对EditText进行监听
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void afterTextChanged(Editable editable) {
                mTextCount.setText("剩余字数：" + (MAX_COUNT - editable.length()));
            }
        });
    }
}