android开发之获取网络数据

最新推荐文章于 2023-07-07 16:15:25 发布

原创最新推荐文章于 2023-07-07 16:15:25 发布 · 3.1k 阅读

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CC 4.0 BY-SA版权

文章标签：

#android #网络 #layout #exception #button #byte

本文介绍了一个简单的Android应用程序，用于从网络加载并显示图片。通过创建一个专门的服务类来处理图片数据的获取，并在Activity中实现按钮点击事件以展示图片。

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android开发之获取网络数据

获取网络图片

首先我们需要把界面搭建好

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" >

 

    <Button

        android:id="@+id/showImageID"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="@string/btn" />

//用来点击事件

 

    <ImageView

        android:id="@+id/imageViewID"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content" />

//用来显示图片

 

</LinearLayout>

接下来我们需要添加ImageService类

package cn.class3g.service;

 

import java.io.ByteArrayOutputStream;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.net.URL;

 

public class ImageService {

   public static byte[] getImageData(String path) throws Exception {

      URL url = new URL(path);

 

      HttpURLConnection conn = (HttpURLConnection) url.openConnection();

 

      conn.setRequestMethod("GET");

 

      conn.setConnectTimeout(5000);

 

      InputStream inStream = conn.getInputStream();

 

      ByteArrayOutputStream bos = new ByteArrayOutputStream();

 

      byte[] buffer = new byte[1024];

      int len = 0;

      while ((len = inStream.read(buffer)) != -1) {

        bos.write(buffer, 0, len);

      }

 

      byte[] data = bos.toByteArray();

 

      return data;

 

   }

}

最后就是我们的activity

package cn.class3g.net;

 

import cn.class3g.service.ImageService;

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ImageView;

import android.widget.Toast;

 

public class ShowImageActivity extends Activity implements OnClickListener {

   Button btn;

   ImageView imageView;

 

   public void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

      setContentView(R.layout.main);

      findViews();

   }

 

   private void findViews() {

      btn = (Button) this.findViewById(R.id.showImageID);

      imageView = (ImageView) this.findViewById(R.id.imageViewID);

      btn.setOnClickListener(this);

   }

 

   @Override

   public void onClick(View v) {

      String path = "http://cimg2.163.com/catchpic/4/44/44ED4853B4A3FE71971C885A0A22825E.jpg";

      try {

        byte data[] = ImageService.getImageData(path);

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

        imageView.setImageBitmap(bitmap);

      } catch (Exception e) {

        Log.e("tag", e.toString());

         Toast.makeText(this, R.string.error, Toast.LENGTH_SHORT).show();

      }

 

   }

}