Android从网络中获得一张图片并显示在屏幕上的实例详解

Android从网络中获得一张图片并显示在屏幕上的实例详解

看下实现效果图：

1：androidmanifest.xml的内容

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="cn.capinftotech.image"
   android:versionCode="1"
   android:versionName="1.0">
  <application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".MainActivity"
         android:label="@string/app_name">
      <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
      </intent-filter>
    </activity> 

  </application>
  <uses-sdk android:minSdkVersion="8" />
  <uses-permission android:name="android.permission.INTERNET" /> 

</manifest>

注意访问网络中的数据需要添加android.permission.INTERNET权限

2：MainActivity的内容

package cn.capinftotech.image; 

import java.io.IOException; 

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.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast; 

import com.capinfotech.service.ImageService; 

public class MainActivity extends Activity {
  private static final String TAG = "MainActivity"; 

  private EditText urlPath = null;
  private Button button = null;
  private ImageView imageView = null; 

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main); 

    urlPath = (EditText)findViewById(R.id.urlpath);
    button = (Button)findViewById(R.id.button);
    imageView = (ImageView)findViewById(R.id.imageView); 

    button.setOnClickListener(new View.OnClickListener() { 

      @Override
      public void onClick(View v) {
        String urlPathContent = urlPath.getText().toString();
        try {
          byte[] data = ImageService.getImage(urlPathContent);
          Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length); //生成位图
          imageView.setImageBitmap(bitmap);  //显示图片
        } catch (IOException e) {
          Toast.makeText(MainActivity.this, R.string.error, Toast.LENGTH_LONG).show(); //通知用户连接超时信息
          Log.i(TAG, e.toString());
        } 

      }
    });
  }
}

3：ImageService类的内容

package com.capinfotech.service; 

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

import com.capinfotech.utils.StreamTool; 

public class ImageService { 

  public static byte[] getImage(String path) throws IOException {
    URL url = new URL(path);
    HttpURLConnection conn = (HttpURLConnection)url.openConnection();
    conn.setRequestMethod("GET");  //设置请求方法为GET
    conn.setReadTimeout(5*1000);  //设置请求过时时间为5秒
    InputStream inputStream = conn.getInputStream();  //通过输入流获得图片数据
    byte[] data = StreamTool.readInputStream(inputStream);   //获得图片的二进制数据
    return data; 

  }
}

4：StreamTool的内容

package com.capinfotech.utils; 

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream; 

public class StreamTool { 

  /*
   * 从数据流中获得数据
   */
  public static byte[] readInputStream(InputStream inputStream) throws IOException {
    byte[] buffer = new byte[1024];
    int len = 0;
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    while((len = inputStream.read(buffer)) != -1) {
      bos.write(buffer, 0, len);
    }
    bos.close();
    return bos.toByteArray(); 

  }
}

5：程序中用到的字符串资源strings.xml里的内容

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <string name="hello">Hello World, MainActivity!</string>
  <string name="app_name">图片浏览器</string>
  <string name="urlpath">网络图片地址</string>
  <string name="button">显示</string>
  <string name="error">网络连接超时</string>
</resources>

6：程序布局文件main.xml的内容

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/urlpath"
  />
<EditText
  android:id="@+id/urlpath"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="http://www.eoeandroid.com/data/attachment/forum/201107/18/142935bbi8d3zpf3d0dd7z.jpg"
  />
<Button
  android:id="@+id/button"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="@string/button"
  />
<ImageView
  android:id="@+id/imageView"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
/>
</LinearLayout>

以上使用Android 获取网路图片并显示的实例，如有疑问请留言或者到本站社区交流讨论，感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！