效果图：

 

 

1.由于需要从网络下载，所以需要获得Android系统应用读取网络的权限<uses-permission android:name="android.permission.INTERNET"/>

2.为了解决连接网络太费时间的问题，所以使用子线程来加载图片。

 

正文：

activity:

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

xmlns:tools="http://schemas.android.com/tools"

android:id="@+id/LinearLayout1"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

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" >

<ImageView

android:id="@+id/ivimg"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_gravity="center"

android:layout_weight="1" />

<EditText

android:id="@+id/eturl"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:ems="10"

android:text="http://pic70.nipic.com/file/20150617/21266988_113316974000_2.jpg" />

<Button

android:id="@+id/btn"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:onClick="btn"

android:layout_gravity="center"

android:text="点击" />

</LinearLayout>

MainActivity：

package com.example.image;

import java.io.IOException;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.net.MalformedURLException;

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.View;

import android.widget.EditText;

import android.widget.ImageView;

import android.widget.Toast;

@SuppressLint("HandlerLeak")

public class MainActivity extends Activity {

private EditText eturl;

private ImageView ivimg;

public static final int SHOWIMAGE=1;

public static final int SHOWFAIL=0;

// Handler 处理事件

private Handler handler=new Handler(){

public void handleMessage(android.os.Message msg) {

switch (msg.what) {

case SHOWIMAGE:

Bitmap bitmap=(Bitmap) msg.obj;

ivimg.setImageBitmap(bitmap);

break;

case SHOWFAIL:

ivimg.setImageResource(R.drawable.keai);

Toast.makeText(MainActivity.this, "显示图片失败", Toast.LENGTH_LONG).show();

break;

default:

break;

}

};

};

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

initViews();

ivimg.setImageResource(R.drawable.keai);

}

// 查找的ID

private void initViews() {

eturl=(EditText) findViewById(R.id.eturl);

ivimg=(ImageView) findViewById(R.id.ivimg);

}

// 按钮点击事件

public void btn(View view){

final String imageUrl=eturl.getText().toString();

if(TextUtils.isEmpty(imageUrl)){

Toast.makeText(this, "图片路径不能为空", Toast.LENGTH_LONG).show();

}else{

new Thread(){

public void run() {

try {

URL url=new URL(imageUrl);

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

httpURLConnection.setRequestMethod("GET");

httpURLConnection.setConnectTimeout(5000);

int responseCode=httpURLConnection.getResponseCode();

if(responseCode==200){

InputStream inputStream=httpURLConnection.getInputStream();

Bitmap bitmap=BitmapFactory.decodeStream(inputStream);

Message message=new Message();

message.what=SHOWIMAGE;

message.obj=bitmap;

//ivImage.setImageBitmap(bitmap);

handler.sendMessage(message);

}else{

Message message=new Message();

message.what=SHOWFAIL;

handler.sendMessage(message);

}

} catch (MalformedURLException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}.start();

}

}

}