OKhttp基本使用介绍

MainActivity.class

 package com.example.administrator.okhttp3;

 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.widget.Button;
 import android.widget.TextView;

 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;

 import okhttp3.Call;
 import okhttp3.Callback;
 import okhttp3.FormBody;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
 import okhttp3.RequestBody;
 import okhttp3.Response;

 public class MainActivity extends AppCompatActivity implements View.OnClickListener {
     private static OkHttpClient client = new OkHttpClient();
     private Request request;
     private Response response;

     private Button button1, button2, button3, button4;
     private TextView textView;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         button1 = (Button) findViewById(R.id.btn_one);
         button2 = (Button) findViewById(R.id.btn_two);
         button3 = (Button) findViewById(R.id.btn_three);
         button4 = (Button) findViewById(R.id.btn_four);
         button1.setOnClickListener(this);
         button2.setOnClickListener(this);
         button3.setOnClickListener(this);
         button4.setOnClickListener(this);
         textView = (TextView) findViewById(R.id.tv);
     }

     @Override
     public void onClick(View view) {
         switch (view.getId()) {
             case R.id.btn_one://同步get
                 client = new OkHttpClient();
                 request = new Request.Builder().url("http://cache.video.iqiyi.com/jp/avlist/202861101/1/?callback=jsonp9").build();
                 new Thread(new Runnable() {
                     @Override
                     public void run() {
                         try {
                             response = client.newCall(request).execute();
                             final String src = response.body().string();
                             Log.e("Tag", response.body().string());
                             runOnUiThread(new Runnable() {
                                 @Override
                                 public void run() {
                                     textView.setText(src);
                                 }
                             });

                         } catch (IOException e) {
                             e.printStackTrace();
                         }
                     }
                 }).start();

                 break;
             case R.id.btn_two://异步get
                 request = new Request.Builder().url("http://cache.video.iqiyi.com/jp/avlist/202861101/1/?callback=jsonp9").build();
                 client.newCall(request).enqueue(new Callback() {
                     @Override
                     public void onFailure(Call call, IOException e) {

                     }

                     @Override
                     public void onResponse(Call call, Response response) throws IOException {
                         final String src = response.body().string();
                         Log.e("Tag", response.body().string());
                         runOnUiThread(new Runnable() {
                             @Override
                             public void run() {
                                 textView.setText(src);
                             }
                         });
                     }
                 });
                 break;
             case R.id.btn_three://提交表单
                 RequestBody requestBody = new FormBody.Builder()
                         .add("search", "papap").build();
                 request = new Request.Builder().url("https://en.wikipedia.org/w/index.php").post(requestBody).build();
                 client.newCall(request).enqueue(new Callback() {
                     @Override
                     public void onFailure(Call call, IOException e) {

                     }

                     @Override
                     public void onResponse(Call call, Response response) throws IOException {
                         final String src = response.body().string();
                         runOnUiThread(new Runnable() {
                             @Override
                             public void run() {
                                 textView.setText(src);
                             }
                         });
                     }
                 });
                 break;
             case R.id.btn_four://文件下载
                 request = new Request.Builder().url("http://pic2.ooopic.com/10/18/01/04bOOOPICb3.jpg").build();
                 client.newCall(request).enqueue(new Callback() {
                     @Override
                     public void onFailure(Call call, IOException e) {

                     }

                     @Override
                     public void onResponse(Call call, Response response) throws IOException {
                         InputStream inputStream = response.body().byteStream();
                         FileOutputStream fileOutputStream = new FileOutputStream(new File("/sdcard/tupian.jpg"));
                         byte[] buffer = new byte[2048];//每次循环读取2K的数据

                         int len = 0;
                         while ((len = inputStream.read(buffer)) != -1) {
                             fileOutputStream.write(buffer, 0, len);
                         }
                         fileOutputStream.flush();

                         runOnUiThread(new Runnable() {
                             @Override
                             public void run() {
                                 textView.setText("文件下载成功。。。");
                             }
                         });
                     }
                 });
                 break;
         }
     }
 }

PS：需要注意的是，在进行同步Get网络请求时，因为都是一个耗时操作，所以需要建立一个子线程去进行请求； 并且，UI界面的更新，必须放在主线程去完成！

activity_main.xml

 <?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"
     android:paddingBottom="@dimen/activity_vertical_margin"
     android:paddingLeft="@dimen/activity_horizontal_margin"
     android:paddingRight="@dimen/activity_horizontal_margin"
     android:paddingTop="@dimen/activity_vertical_margin"
     tools:context="com.example.administrator.okhttp3.MainActivity">

     <Button
         android:id="@+id/btn_one"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="同步get" />

     <Button
         android:id="@+id/btn_two"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="异步get" />

     <Button
         android:id="@+id/btn_three"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="Post提交表单" />

     <Button
         android:id="@+id/btn_four"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="文件下载" />

     <TextView
         android:id="@+id/tv"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="text"/>
 </LinearLayout>