Okhttp3基本使用-异步GET请求

代码

package com.example.okhttp3gettest;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import java.io.IOException;

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

public class MainActivity extends AppCompatActivity {
    TextView mTextView=null;
    Handler mHandler = new Handler(){
        public void handleMessage(Message msg){
            if(msg.what==1){
                mTextView.setText(msg.obj.toString());
            }else{
                mTextView.setText("onFailure");
            }
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //okHttpTest();
        init();

    }
    private void init(){
        mTextView = findViewById(R.id.id_text_view);
        okHttpTest();
    }

    public void okHttpTest(){
        String url = "http://wwww.baidu.com";
        OkHttpClient okHttpClient = new OkHttpClient();
        final Request request = new Request.Builder()
                .url(url)
                .get()//默认就是GET请求，可以不写
                .build();
        Call call = okHttpClient.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                mHandler.sendEmptyMessage(2);
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                //mTextView.setText(response.body().string());
                Message msg = new Message();
                msg.what=1;
                msg.obj = response.body().string();
                mHandler.sendMessage(msg);
            }
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/id_text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.okhttp3gettest">
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:networkSecurityConfig="@xml/network_security_config"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

联网设置（rex/xml/network_security_config.xml）

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

运行结果

由okhttp=>Retrofit2+Rxjava2的网络请求变化分析