加载网络图片

1.首先写一个布局文件，一个ImangeView用于存放图片的位置，放置一个Button控件。

2.在Strings.xml文件中添加要查看图片的地址。

3.当界面创建好后，需要在MainActivity里面编写与界面交互的的代码。用于实现请求网络地址的网络图片，并将服务器返回的图片展示在界面上。在MainActivity.java中创建一个子线程，通过这个子线程来获取图片。

4.查看成功的结果。

activity_main.xml布局文件中的代码：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    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="cn.edu.bzu.imagebrowser.MainActivity">    <ImageView        android:id="@+id/ivImage"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_gravity="center"        android:layout_weight="1"        />    <EditText        android:id="@+id/etImageUrl"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:ems="10"        android:hint="请输入图片的路径"        android:text="@string/address" />    <Button        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:onClick="viewImage"        android:text="浏览"  /></LinearLayout>

MainActivity.java中的代码：

package cn.edu.bzu.imagebrowser;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.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 EditText etImageUrl;    private ImageView ivImage;    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;                    ivImage.setImageBitmap(bitmap);                    break;                case SHOWFAIL:                    ivImage.setImageResource(R.drawable.button_bg);                    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();        ivImage.setImageResource(R.drawable.button_bg);    }    // 查找的ID    private void initViews() {        etImageUrl=(EditText) findViewById(R.id.etImageUrl);        ivImage=(ImageView) findViewById(R.id.ivImage);    }    // 按钮点击事件    public void viewImage(View view){        final String imageUrl=etImageUrl.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();                        Message message=new Message();                        message.what=SHOWFAIL;                        handler.sendMessage(message);                    }                }            }.start();        }    }}

清单文件中代码：

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="cn.edu.bzu.imagebrowser">    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application>    <uses-permission android:name="android.permission.INTERNET"></uses-permission></manifest>