Handler+HttpURLConnection请求网络图片,字符串

最新推荐文章于 2022-08-12 20:17:21 发布

原创最新推荐文章于 2022-08-12 20:17:21 发布 · 575 阅读

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文章标签：

#json #handler机制 #httpurlconnection-线程

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本文介绍了如何在Android应用中实现网络请求获取JSON数据及图片资源，并展示了如何使用线程和Handler机制更新UI显示网络图片。

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请求Json串

package com.bawei.wzq.test;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
* ctrl+alt+l–代码格式化;
* alt+enter—快捷提示
*/

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    new Thread() {
        @Override
        public void run() {
            super.run();
            //联网是耗时操作,要放在子线程
            try {
                //定义一个url对象
                URL url = new URL("https://api.tianapi.com/wxnew/?key=8d6e3228d25298f13af4fc40ce6c9679&num=10&page=1");
                //通过url打开连接;
                URLConnection urlConnection = url.openConnection();
                //服务器返回的数据都是以流的形式;
                InputStream inputStream = urlConnection.getInputStream();//得到输入流
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));

                StringBuilder stringBuilder = new StringBuilder();
                String stringTemp = "";
                while ((stringTemp = bufferedReader.readLine()) != null) {
                    stringBuilder.append(stringTemp);
                }
                //流转化为字符串
                String result = stringBuilder.toString();
                //打印在控制台上
                Log.e("wzq", "onCreate: result:" + result);

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

请求网络图片

package com.bawei.wzq.test;

import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

/**
* ctrl+alt+l–代码格式化;
* alt+enter—快捷提示
* ctrl+alt+F–>提取全局变量
*/

public class MainActivity extends AppCompatActivity {

private ImageView iv;
Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
        int what = msg.what;
        if (what == 1) {
            //Bitmap封装了图片
            iv.setImageBitmap((Bitmap) msg.obj);
        }
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    iv = (ImageView) findViewById(R.id.iv);
    //点击事件
    iv.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            new Thread(
                    new Runnable() {
                        @Override
                        public void run() {
                            String url = "https://img-my.youkuaiyun.com/uploads/201407/26/1406383299_1976.jpg";
                            NetWorkUtil netWorkUtil = new NetWorkUtil();
                            Bitmap netImage = netWorkUtil.getNetImage(url);
                            //Message mm = new Message();
                            //得到message;
                            Message message = handler.obtainMessage();
                            message.obj = netImage;//封装参数
                            //让handler判断;
                            message.what = 1;
                            handler.sendMessage(message);
                        }
                    }
                ).start();
            }
        });
    }
}

布局

    <ImageView
    android:id="@+id/iv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="8dp"
    android:layout_marginTop="8dp"/>

请求网络类
package com.bawei.wzq.test;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class NetWorkUtil {

private int responseCode;

public Bitmap getNetImage(String urlString){
    try {
        //得到URL对象,这个对象可以打开连接
        URL url = new URL(urlString);
        //打开连接,HttpURLConnection:是URLConnection的子类;子类的方法比较多;都用子类
        HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
        //服务器返回的状态码
        int responseCode = urlConnection.getResponseCode();
        //请求成功
        if (responseCode == 200){
            InputStream inputStream = urlConnection.getInputStream();
            //BitmapFactory类封装了好多关于图片处理的方法;
            Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
            return  bitmap;

        }else {
            Log.e("wzq","responseCode:"+ responseCode);
        }

    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
    }
}