5、完成以上4个步骤后，部分手机上用不了（如果您使用的是http，Android9.0手机是用不了的，看本博客的“Android P不能使用http”解决不能使用http的方法）。
在build.gradle导入okHttp3（加入进去后记得在Android studio的右上角点击“Sync Now”同步）
implementation 'com.squareup.okhttp3:okhttp:3.4.1' //okhttp3
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
tools:context=".MainActivity">
<ImageView
android:id="@+id/iv"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_centerHorizontal="true"
android:layout_marginTop="40dp"
android:background="@drawable/dongman"/>
<LinearLayout
android:id="@+id/ll_number"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/iv"
android:layout_centerVertical="true"
android:layout_marginTop="15dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginBottom="5dp"
android:background="#ffffff">
<TextView
android:id="@+id/tv_number"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="账号"
android:textColor="#000"
android:textSize="20sp"/>
<EditText
android:id="@+id/et_number"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:background="@null"
android:padding="10dp"/>
</LinearLayout>
<LinearLayout
android:id="@+id/ll_password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/ll_number"
android:layout_centerVertical="true"
android:layout_marginTop="15dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginBottom="5dp"
android:background="#ffffff">
<TextView
android:id="@+id/tv_password"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="密码"
android:textColor="#000"
android:textSize="20sp"/>
<EditText
android:id="@+id/et_password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:background="@null"
android:padding="10dp"/>
</LinearLayout>
<Button
android:id="@+id/btn_login"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/ll_password"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="30dp"
android:text="登录"
android:background="#3C8DC4"
android:textSize="20sp"/>
</RelativeLayout>
package com.example.remembernp;
import android.content.Context;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.HashMap;
import java.util.Map;
public class SaveFile {
//把账号密码保存在data.txt文件中
public static boolean saveUserInfo(Context context, String number, String password){
try{
FileOutputStream fos = context.openFileOutput("data.txt",Context.MODE_PRIVATE);
fos.write((number + ":" + password).getBytes());
fos.close();
return true;
}catch (Exception e){
e.printStackTrace();
return false;
}
}
//从data.txt中去获取刚刚保存的账号密码
public static Map<String,String> getUserInfo(Context context) {
String content = "";
try {
FileInputStream fis = context.openFileInput("data.txt");
byte[] buffer = new byte[fis.available()];
fis.read(buffer);//读取
content = new String(buffer);
Map<String ,String > userMap = new HashMap<String, String>();
String[] infos = content.split(":");
userMap.put("number",infos[0]);
userMap.put("password",infos[1]);
fis.close();
return userMap;
}catch (Exception e){
e.printStackTrace();
return null;
}
}
}
package com.example.remembernp;
import androidx.appcompat.app.AppCompatActivity;
import android.app.AlertDialog;
import android.icu.util.LocaleData;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Map;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private EditText etNumber;
private EditText etPassword;
private Button btnLogin;
private MediaType mediaType;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = (Button)findViewById(R.id.btn_login);
Map<String,String> userInfo = SaveFile.getUserInfo(this);
initView();
if(userInfo != null){
etNumber.setText(userInfo.get("number"));
etPassword.setText(userInfo.get("password"));
}
}
private void initView(){
etNumber = (EditText)findViewById(R.id.et_number);
etPassword = (EditText)findViewById(R.id.et_password);
btnLogin = (Button)findViewById(R.id.btn_login);
btnLogin.setOnClickListener(this);
}
@Override
public void onClick(View view) {
//单击事件，获取账号密码
final String number = etNumber.getText().toString().trim();
String password = etPassword.getText().toString().trim();
//检查账号密码是否正确
if(TextUtils.isEmpty(number)){
Toast.makeText(this, "请输入账号", Toast.LENGTH_SHORT).show();
return;
}
if(TextUtils.isEmpty(password)){
Toast.makeText(this, "请输入密码", Toast.LENGTH_SHORT).show();
return;
}
okHttp(); //登录
}
private void okHttp(){
//单击事件，获取账号密码
final String number = etNumber.getText().toString().trim();
final String password = etPassword.getText().toString().trim();
//给密码加密
final String md5 = md5Decode(password + "dabsdafaqj23ou89ZXcj@#$@#$#@KJdjklj;D../dSF.,");
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
JSONObject jsonObject = new JSONObject();
jsonObject.put("number",number);
jsonObject.put("password",md5);
mediaType = MediaType.parse("application/json;charest=utf-8");
RequestBody requestBody = RequestBody.create(mediaType,jsonObject.toString());
final Request request = new Request.Builder() .url("使用自己的登录网址")
.post(requestBody).build();
client.newCall(request).enqueue(new Callback() {
@Override
//请求失败
public void onFailure(Call call, IOException e) {
Log.d("请求失败","，返回码："+e.getMessage());
loginRemind(400);
}
@Override
//请求成功
public void onResponse(Call call, final Response response) throws IOException {
loginRemind(response.code());
if(response.code() == 200){
Log.d("请求成功---------","后台返回数据："+response.body().string());
//保存账号密码
SaveFile.saveUserInfo(MainActivity.this,number,password);
}else{
Log.d("请求成功-----但登录失败----返回码："+response.code(),"------失败原因："+response.body().string());
}
}
});
} catch (JSONException e) {
e.printStackTrace();
}
}
}).start();
}
public String md5Decode(String content) {
byte[] hash;
try {
hash = MessageDigest.getInstance("MD5").digest(content.getBytes("UTF-8"));
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("NoSuchAlgorithmException", e);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("UnsupportedEncodingException", e);
}
//对生成的16字节数组进行补零操作
StringBuilder hex = new StringBuilder(hash.length * 2);
for (byte b : hash) {
if ((b & 0xFF) < 0x10) {
hex.append("0");
}
hex.append(Integer.toHexString(b & 0xFF));
}
return hex.toString();
}
private void loginRemind(final int num){
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
switch (num){
case 200:
Toast.makeText(MainActivity.this, "登录成功", Toast.LENGTH_LONG).show();
break;
case 400:
Toast.makeText(MainActivity.this, "请求失败", Toast.LENGTH_LONG).show();
break;
default:
Toast.makeText(MainActivity.this, "请求成功，登录失败，返回码："+num, Toast.LENGTH_LONG).show();
break;
}
}
});
}
}