从网络获取图片示例

本示例使用于4.0一下的Android系统

1、编写activity_main.xml文件

<LinearLayout 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:orientation="vertical"
    tools:context=".MainActivity" >

    <ImageView
        android:id="@+id/iv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1000" />

    <EditText
        android:id="@+id/et"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:text="http://g.hiphotos.baidu.com/image/w%3D2048/sign=94bc5b60a50f4bfb8cd0995437777af0/86d6277f9e2f07083e861effe824b899a801f249.jpg" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="click"
        android:text="commit" />

</LinearLayout>

2、编写MainActivity.java文件

package com.example.picturelook;

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

import org.apache.http.HttpConnection;

import android.os.Bundle;
import android.R.integer;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private ImageView iView;
    private EditText editText;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        iView=(ImageView)findViewById(R.id.iv);
        editText=(EditText)findViewById(R.id.et);
    }
    public void click(View view)
    {
        String path=editText.getText().toString().trim();
        if (TextUtils.isEmpty(path)) {
            Toast.makeText(this, "图片路径不能为空", 0).show();
        }else {
            try {
                //创建uRL链接
                URL url=new URL(path);
                //根据url发送Http请求
                HttpURLConnection conn=(HttpURLConnection) url.openConnection();
                //设置请求方式/请求属性/读取超时时间/连接超时时间
                conn.setRequestMethod("GET");
                conn.setRequestProperty("User-Agent", "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)");
                conn.setReadTimeout(3000);
                conn.setConnectTimeout(5000);
                
                //得到请求响应码
                int code=conn.getResponseCode();
                if (code==200) {
                    //获得图片输入流
                    InputStream inputStream=conn.getInputStream();
                    //将输入流转换成bitmap对象
                    Bitmap bitmap=BitmapFactory.decodeStream(inputStream);
                    iView.setImageBitmap(bitmap);
                    }else {
                    Toast.makeText(this, "图片请求失败", 0).show();
                }
                
                
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                Toast.makeText(this, "图片显示失败", 0).show();
            }
        }
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}

3、添加权限

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.picturelook"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.picturelook.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>

</manifest>

demo下载

 

以下是适配安装4.0及以上系统的代码

package com.example.picturelook;

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


import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private ImageView iView;
    private EditText editText;
    
    @SuppressLint("HandlerLeak")
    private Handler handler=new Handler(){
        public void handleMessage(Message msg) {
            if (msg.what==1) {
                Bitmap bitmap=(Bitmap) msg.obj;
                iView.setImageBitmap(bitmap);
            }
        };
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        iView=(ImageView)findViewById(R.id.iv);
        editText=(EditText)findViewById(R.id.et);
    }
    public void click(View view)
    {
        final String path=editText.getText().toString().trim();
        new Thread(new Runnable() {
            
            @Override
            public void run() {
                // TODO Auto-generated method stub
                if (TextUtils.isEmpty(path)) {
                    Toast.makeText(MainActivity.this, "图片路径不能为空", 0).show();
                }else {
                    try {
                        //创建uRL链接
                        URL url=new URL(path);
                        //根据url发送Http请求
                        HttpURLConnection conn=(HttpURLConnection) url.openConnection();
                        //设置请求方式/请求属性/读取超时时间/连接超时时间
                        conn.setRequestMethod("GET");
                        conn.setRequestProperty("User-Agent", "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)");
                        conn.setReadTimeout(3000);
                        conn.setConnectTimeout(5000);
                        
                        //得到请求响应码
                        int code=conn.getResponseCode();
                        if (code==200) {
                            //获得图片输入流
                            InputStream inputStream=conn.getInputStream();
                            //将输入流转换成bitmap对象
                            Bitmap bitmap=BitmapFactory.decodeStream(inputStream);
                            Message msg=new Message();
                            msg.what=1;
                            msg.obj=bitmap;
                            handler.sendMessage(msg);
                            }else {
                            Toast.makeText(MainActivity.this, "图片请求失败", 0).show();
                        }
                        
                        
                    } catch (Exception e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                        Toast.makeText(MainActivity.this, "图片显示失败", 0).show();
                    }
                }
            }
        }).start();
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}