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>