【Android】OKHTTP使用

如果饿了就吃，困了就睡，渴了就喝，人生就太无趣了
参考博客：https://blog.csdn.net/wsq_tomato/article/details/80301851
Android源码地址：https://github.com/keer123456789/OkHttpExample.git
Springboot后台地址：https://github.com/keer123456789/OkHttpServer.git

1.安装依赖

本次使用的是OKHTTP的3.4.1版本

// https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp
implementation group: 'com.squareup.okhttp3', name: 'okhttp', version: '3.4.1'

2.更改配置

2.1 增加权限

在AndroidManifest.xml中增加下面两行权限

<manifest>......<uses-permission android:name="android.permission.INTERNET" /><uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>......
</manifest>

2.2 添加配置文件

2.2.1 增加xml文件

在资源文件夹res中添加network_security_config.xml（名字随意）,内容如下

<?xml version="1.0" encoding="utf-8"?>
<network-security-config><base-config cleartextTrafficPermitted="true" />
</network-security-config>

如图1，创建注意选择xml

目录结构如图2

2.2.2 更改`AndroidManifest.xml`文件

在AndroidManifest.xml文件中引用刚刚增加的xml文件

android:networkSecurityConfig="@xml/network_security_config"

3.后台接口

后台接口使用SpringBoot开启了一个web服务，有两个接口，分别测试GET和POST方法。

3.1 GET 接口

GET /android/getTest/{info}返回：Get success

3.2 POST接口

POST /android/postTest/
Data example：
{   "name":"keer","pass":"123456"
}返回：POST success

3.3 后台代码

/*** @BelongsProject: okhttpserver* @BelongsPackage: com.keer.okhttpserver.Controller* @Author: keer* @CreateTime: 2020-02-29 22:13* @Description: android使用OkHttp后台接口*/
@RestController()
@RequestMapping("/android")
public class Controller {private Logger logger = LoggerFactory.getLogger(Controller.class);@RequestMapping(value = "/getTest/{info}", method = RequestMethod.GET)public String getMethod(@PathVariable String info) {logger.info("接收到Get请求，传来的信息：" + info);return "Get success";}@RequestMapping(value = "/postTest", method = RequestMethod.POST)public String postMethod(@RequestBody Map map) {logger.info("接收到POST请求，传来的信息：" + map.toString());return "Post success!!!";}
}

4.Android 中的Activity的XML文件

4.1 代码

<?xml version="1.0" encoding="utf-8"?>
<TableLayout 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"android:stretchColumns="1"tools:context=".MainActivity"><TableRow><TextViewandroid:layout_height="wrap_content"android:text="Account：" /><EditTextandroid:id="@+id/account"android:layout_height="wrap_content"android:hint="Input your account" /></TableRow><TableRow><TextViewandroid:layout_height="wrap_content"android:text="PassWord：" /><EditTextandroid:id="@+id/password"android:layout_height="wrap_content"android:inputType="textPassword" /></TableRow><Buttonandroid:id="@+id/get"style="@style/Widget.AppCompat.Button"android:layout_width="125dp"android:layout_height="wrap_content"android:text="GET" /><Buttonandroid:id="@+id/post"android:layout_width="match_parent"android:layout_height="wrap_content"android:minWidth="32dp"android:text="POST" />
</TableLayout>

4.2 图片展示

如图3，模拟登陆界面。

点击GET按钮，会获取Account的输入框的值，作为/android/getTest/{info}接口的info参数；
点击POST按钮，会获取Account和PassWord输入框的值，作为/android/postTest/接口的传送数据。

5.OKHTTP使用方法

5.1 GET方法使用

 /*** @param info 接口中info值* @return*/public String myGet(String info) {OkHttpClient client = new OkHttpClient();//构建请求，request中默认是get方法，所以将.get()删去也不要紧Request request = new Request.Builder().url("http://192.168.0.101:8080/android/getTest/" + info)//.get() //加上和删去都不要紧.build();Response response = null;String responseData = null;try {response = client.newCall(request).execute();responseData = response.body().string();} catch (IOException e) {e.printStackTrace();}System.out.println("成功接收到返回值" + responseData);return responseData;}

5.2 POST方法使用

    public String myPost() throws Exception {OkHttpClient client = new OkHttpClient();//构建请求头final MediaType JSON = MediaType.parse("application/json; charset=utf-8");//构建JSON数据，作为传送的数据JSONObject jsonObject = new JSONObject();jsonObject.put("name", "keer");jsonObject.put("pass", "123456");//构建RequestBodyRequestBody body = RequestBody.create(JSON, jsonObject.toString());//这里是需要是json字符串//构建请求requestRequest request = new Request.Builder().url("http://192.168.0.101:8080/android/postTest").post(body) //将RequestBody作为post方法的参数。.build();Response response = client.newCall(request).execute();String res = response.body().string();System.out.println(res);return res;}

6.主线程和子线程

本人Android小小白，也是看别人的讲解，加上自己的理解，这一部分如有说错，谅解，欢迎指正！！！

6.1 android网络请求

自从android4.0之后，网络请求需要开启线程，原因：

为了避免导致UI卡顿的情况：比如在OnCreate 里面先进行网络请求然后还要加载布局。
一般大型软件开发时，负责网络通信的，和对数据做处理的，往往是两个不同的模块
这样通过回调的方式，使代码的耦合性降低，更易于分块。

Android提供了一个消息传递的机制——Handler，来帮助线程之间的通信。

6.2 Handler使用介绍

6.2.1 主线程中创建Handler

在主线程中创建一个Handler实例，，并重写handleMessage()方法，该方法就是子线程动作完成后，需要主线程做的动作。可以看到线程中的通信是通过Message对象实现的。该方法中使用了switch,说明会有两个子线程会发来消息，就是后面调用的post和get方法的子线程。switch中的两个动作分别使用Toast对象显示子线程发来的信息。Message对象会在后面介绍。

Handler handler = new Handler() {@Overridepublic void handleMessage(Message msg) {switch (msg.what){case 1:{Toast.makeText(MainActivity.this, "Get方法成功接收到返回值" + msg.obj.toString(), Toast.LENGTH_SHORT).show();}break;case 2:{Toast.makeText(MainActivity.this, "Post方法成功接收到返回值" + msg.obj.toString(), Toast.LENGTH_SHORT).show();}break;}}
};

6.2.2 子线程中发送消息

① GET方法的子线程

 private void getTest(final String name) {new Thread(new Runnable() {@Overridepublic void run() {OkHttpClient client = new OkHttpClient();Request request = new Request.Builder().url("http://192.168.0.101:8080/android/getTest/" + name).build();Response response = null;String responseData = null;try {response = client.newCall(request).execute();responseData = response.body().string();} catch (IOException e) {e.printStackTrace();}System.out.println("成功接收到返回值" + responseData);Message message = handler.obtainMessage(1);message.obj = responseData;handler.sendMessage(message);}}).start();}

② POST方法子线程

 private void postTest(final JSONObject map) {new Thread(new Runnable() {@Overridepublic void run() {OkHttpClient client = new OkHttpClient();final MediaType JSON = MediaType.parse("application/json; charset=utf-8");//发送json数据的固定写法JSONObject jsonObject = new JSONObject();RequestBody body = RequestBody.create(JSON, map.toString());//这里是需要是json字符串Request request = new Request.Builder().url("http://192.168.0.101:8080/android/postTest")//用安卓虚拟器跑也不要用127.0.0.1.post(body).build();String res = null;try {Response response = client.newCall(request).execute();res = response.body().string();System.out.println(res);Message message = handler.obtainMessage(2);message.obj = res;handler.sendMessage(message);} catch (IOException e) {e.printStackTrace();}}}).start();}

可以看出发送消息的主要代码就是下面这三行:

通过已经实例化的handler中obtainMessage()方法实例化Message对象。参数是Message.what的值。
将传送的数据赋值给Message的obj变量。
最后调用sendMessage()方法发送消息

 Message message = handler.obtainMessage(2);message.obj = data;handler.sendMessage(message);

6.3 Message介绍

通过上面的说明，已经了解Message对象就是线程之间通信的对象，贴出部分声明变量的源码：

what就是标记作用，用来区分不同的Message
arg1和arg2是用来存放需要传递的整数值
org传送子线程中的实例化的对象。

    /*** User-defined message code so that the recipient can identify* what this message is about. Each {@link Handler} has its own name-space* for message codes, so you do not need to worry about yours conflicting* with other handlers.*/public int what;/*** arg1 and arg2 are lower-cost alternatives to using* {@link #setData(Bundle) setData()} if you only need to store a* few integer values.*/public int arg1;/*** arg1 and arg2 are lower-cost alternatives to using* {@link #setData(Bundle) setData()} if you only need to store a* few integer values.*/public int arg2;/*** An arbitrary object to send to the recipient.  When using* {@link Messenger} to send the message across processes this can only* be non-null if it contains a Parcelable of a framework class (not one* implemented by the application).   For other data transfer use* {@link #setData}.** <p>Note that Parcelable objects here are not supported prior to* the {@link android.os.Build.VERSION_CODES#FROYO} release.*/public Object obj;

6.4 全部代码

MainActivity.java中的全部代码如下

public class MainActivity extends AppCompatActivity implements View.OnClickListener {public static final int SHOW_RESPONSE = 0;private Button getbt;private Button postbt;private EditText accountEdit;private EditText passwordEdit;private Handler handler;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);getbt = (Button) findViewById(R.id.get);postbt = (Button) findViewById(R.id.post);accountEdit = (EditText) findViewById(R.id.account);passwordEdit = (EditText) findViewById(R.id.password);getbt.setOnClickListener(this);postbt.setOnClickListener(this);handler = new Handler() {@Overridepublic void handleMessage(Message msg) {switch (msg.what){case 1:{Toast.makeText(MainActivity.this, "Get方法成功接收到返回值" + msg.obj.toString(), Toast.LENGTH_SHORT).show();}break;case 2:{Toast.makeText(MainActivity.this, "Post方法成功接收到返回值" + msg.obj.toString(), Toast.LENGTH_SHORT).show();}break;}}};}@Overridepublic void onClick(View v) {String name = accountEdit.getText().toString();String pass = passwordEdit.getText().toString();if (v.getId() == R.id.post) {JSONObject j = new JSONObject();try {j.put("name", name);j.put("pass", pass);} catch (JSONException e) {e.printStackTrace();}postTest(j);} else if (v.getId() == R.id.get) {getTest(name);}}@Overridepublic void onPointerCaptureChanged(boolean hasCapture) {}/*** 发送get请求** @param name*/private void getTest(final String name) {new Thread(new Runnable() {@Overridepublic void run() {OkHttpClient client = new OkHttpClient();Request request = new Request.Builder().url("http://192.168.0.101:8080/android/getTest/" + name).build();Response response = null;String responseData = null;try {response = client.newCall(request).execute();responseData = response.body().string();} catch (IOException e) {e.printStackTrace();}System.out.println("成功接收到返回值" + responseData);Message message = handler.obtainMessage(1);message.obj = responseData;handler.sendMessage(message);}}).start();}/*** 发送POST请求** @param map*/private void postTest(final JSONObject map) {new Thread(new Runnable() {@Overridepublic void run() {OkHttpClient client = new OkHttpClient();final MediaType JSON = MediaType.parse("application/json; charset=utf-8");//发送json数据的固定写法JSONObject jsonObject = new JSONObject();RequestBody body = RequestBody.create(JSON, map.toString());//这里是需要是json字符串Request request = new Request.Builder().url("http://192.168.0.101:8080/android/postTest")//用安卓虚拟器跑也不要用127.0.0.1.post(body).build();String res = null;try {Response response = client.newCall(request).execute();res = response.body().string();System.out.println(res);Message message = handler.obtainMessage(2);message.obj = res;handler.sendMessage(message);} catch (IOException e) {e.printStackTrace();}}}).start();}
}