Android获取网络上的图片
fmms
13年前
网络的访问在我们日常生活中太重要了,如果没有网络我们的生活将会是什么样子呢?android手机和浏览器也是一样的,也可以通过网络通讯获取数据,如调用webservice,EJB等。下面就通过一个小例子从网络获取一幅图片并显示在手机上,开发中将会使用到一个新的组件ImageView.
1.写一个用来处理字节流的工具类
package org.lxh.util; import java.io.ByteArrayOutputStream; import java.io.InputStream; public class StreamTool { public static byte[] readInputStream(InputStream in) throws Exception{ int len=0; byte buf[]=new byte[1024]; ByteArrayOutputStream out=new ByteArrayOutputStream(); while((len=in.read(buf))!=-1){ out.write(buf,0,len); //把数据写入内存 } out.close(); //关闭内存输出流 return out.toByteArray(); //把内存输出流转换成byte数组 } }2.写一个得到图片byte数组的service类
package org.lxh.service; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import org.lxh.util.StreamTool; import android.util.Log; public class WebService { public static byte[] getImage(String path){ URL url; byte[] b=null; try { url = new URL(path); //设置URL HttpURLConnection con; con = (HttpURLConnection)url.openConnection(); //打开连接 con.setRequestMethod("GET"); //设置请求方法 //设置连接超时时间为5s con.setConnectTimeout(5000); InputStream in=con.getInputStream(); //取得字节输入流 b=StreamTool.readInputStream(in); } catch (Exception e) { e.printStackTrace(); } return b; //返回byte数组 } }3.写一个用户操作界面
<?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/hello" /> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/picaddress" /> <EditText android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="http://www.desk9.com/Desk9Image/21/Desk9_21_1690_35790_S.jpg" android:id="@+id/imageaddress" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/look" android:id="@+id/button" /> <ImageView android:layout_width="fill_parent" android:layout_height="fill_parent" android:id="@+id/image"/> </LinearLayout>4.写一个activity类
package org.lxh.net; import org.lxh.service.WebService; 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; public class NetActivity extends Activity { private EditText picaddress; private Button button; private ImageView imageView; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); button=(Button)this.findViewById(R.id.button); imageView=(ImageView)this.findViewById(R.id.image); picaddress=(EditText)this.findViewById(R.id.imageaddress); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { String address=picaddress.getText().toString(); try { byte[] data=WebService.getImage(address); //得到图片的输入流 //二进制数据生成位图 Bitmap bit=BitmapFactory.decodeByteArray(data, 0, data.length); imageView.setImageBitmap(bit); } catch (Exception e) { Log.e("NetActivity", e.toString()); Toast.makeText(NetActivity.this, R.string.error, 1).show(); } } }); } }5.添加网络访问的权限
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="org.lxh.net" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".NetActivity" 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="7" /> <uses-permission android:name="android.permission.INTERNET"/> </manifest>6.这里把strings.xml文件也贴出来
<?xml version="1.0" encoding="utf-8"?> <resources> <string name="hello">Hello World, NetActivity!</string> <string name="app_name">图片查看</string> <string name="picaddress">图片地址</string> <string name="look">查看</string> <string name="error">网络连接异常</string> </resources>下面是运行效果图,代码我也上传给大家。
来自:http://blog.csdn.net/chenwill3/article/details/7240587