关于对OKHttp的简单使用

<?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”

<Button

android:id=“@+id/btn”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:text=“点击下载” />

<ImageView

android:id=“@+id/iview”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:src=“@mipmap/ic_launcher”/>

<ProgressBar

android:id=“@+id/bar”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:max=“100”

style=“@android:style/Widget.ProgressBar.Horizontal”/>

下面就是今天的重头戏——okhttp了。下面请看代码；

package com.example.acer_pc.threedownload;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.support.v7.app.AppCompatActivity;

import android.view.View;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.ProgressBar;

import com.squareup.okhttp.Call;

import com.squareup.okhttp.Callback;

import com.squareup.okhttp.OkHttpClient;

import com.squareup.okhttp.Request;

import com.squareup.okhttp.Response;

import com.squareup.okhttp.ResponseBody;

import java.io.IOException;

public class MainActivity extends AppCompatActivity {

private Button button;

private ImageView imageView;

private ProgressBar bar;

//声明Handler对象，进行对ui的更改

private Handler handler = new Handler(){

@Override

public void handleMessage(Message msg) {

super.handleMessage(msg);

Bitmap bitmap = (Bitmap) msg.obj;

imageView.setImageBitmap(bitmap);

}

};

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//调用查找控件的方法

initFindView();

//button按钮的监听事件，当点击按钮时，实现progressbar进度条消失并下载图片

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

downLoad();

for (int i = 0; i <= 100 ; i++) {

bar.setProgress(i);

}

//进度条消失的方法

bar.setVisibility(View.GONE);

}

private void downLoad() {

//创建客户端对象

OkHttpClient client = new OkHttpClient();

//创建请求对象

Request request = new Request.Builder().url(“http://img04.taobaocdn.com/bao/uploaded/i4/15639020891997878/T12_pTXrlXXXXXXXXX_!!0-item_pic.jpg”).build();

//创建call对象，请求网络，并且将数据返回

Call call = client.newCall(request);

//执行请求

call.enqueue(new Callback() {

//请求失败时的方法

@Override

public void onFailure(Request request, IOException e) {

System.out.println(e.toString());

}

//请求成功时的方法

@Override

public void onResponse(Response response) throws IOException {

//网络请求成功时的反应对象

ResponseBody body = response.body();

//通过body对象获取网络数据

//InputStream inputStream = body.byteStream();

//获取读取流的长度，表示获取数据的总的大小

// long length = body.contentLength();

byte[] bytes = body.bytes();

//通过位图加工厂，将所下载的图片转换为字节发送到主线程

Bitmap bitmap = BitmapFactory.decodeByteArray(bytes,0,bytes.length);

if (bitmap != null){

Message message = handler.obtainMessage();

message.obj = bitmap;

handler.sendMessage(message);

}

}

});