Edittext和TextView的聯動

本文主要通過為edittext新增監聽事件實現它和textview的實時聯動

package com.bwie.edit;

import android.os.Bundle;
import android.support.annotation.MainThread;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextUtils;
import android.text.TextWatcher;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.math.BigInteger;
import java.util.Map;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.edit)
    EditText edit;
    @BindView(R.id.text)
    TextView text;
    @BindView(R.id.get)
    Button get;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        //新增edittext的監聽事件
        edit.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) {
                if (!TextUtils.isEmpty(s)) {
                    // int a = Integer.parseInt(s.toString());
                    BigInteger a = new BigInteger(s.toString());
                    text.setText(BigInteger.valueOf(10000).subtract(a) + "");
                } else {
                    text.setText(s);
                }
            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });
    }

    @OnClick(R.id.get)
    public void onViewClicked() {
        Toast.makeText(MainActivity.this, text.getText().toString(), Toast.LENGTH_SHORT).show();
    }
}

//佈局檔案

<?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:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.bwie.edit.MainActivity">

    <EditText
        android:id="@+id/edit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="顯示" />
<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/get"
    android:text="獲得資料"
    />
</LinearLayout>