Android学习笔记_12_网络通信之从web获取资源数据到Android

<uses-permission android:name="android.permission.INTERNET"/>

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<Button
android:id="@+id/btnImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="34dp"
android:layout_marginTop="15dp"
android:text="查看图片" />

<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/btnImage"
android:layout_below="@+id/btnImage"
android:layout_marginTop="20dp"
/>

</RelativeLayout>

package com.example.image;

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

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity {
private Button button = null;
private ImageView imageView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) this.findViewById(R.id.btnImage);
imageView = (ImageView) this.findViewById(R.id.imageView);
final String path="http://192.168.8.103:8080/Simple/0001.jpg";
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
try {
byte[] data = getImage(path);
Bitmap bm=BitmapFactory.decodeByteArray(data, 0, data.length);
imageView.setImageBitmap(bm);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* 获取图片流
* @param path
* @return
* @throws Exception
*/
public static byte[] getImage(String path) throws Exception{
//创建URL对象，获取HttpURLConnection
HttpURLConnection conn = (HttpURLConnection) new URL(path).openConnection();
conn.setConnectTimeout(5000);
conn.setRequestMethod("GET");
if (conn.getResponseCode()==200) {
//处理从web返回的资源数据
return read(conn.getInputStream());
}
return null;
}
/**
* 将流转化成字节数组
* @param in
* @return
* @throws Exception
*/
public static byte[] read(InputStream in) throws Exception{
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int len=0;
while((len=in.read(buf))!=-1){
outputStream.write(buf,0,len);
}
outputStream.close();
return outputStream.toByteArray();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}