Android----网络图片游览器

1.1任务描述

     输入网络图片的地址，点击浏览按钮可以显示网络中的图片。

1.2 任务实现

1. 训练目标

1) 掌握HttpURLConnection的基本用法

2) HttpClient的基本用法

2、运行项目为：

实现代码如下：

在activity_main.xml

<?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"    tools:context="cn.edu.bzu.imageview.MainActivity">    <ImageView        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:id="@+id/iv"        android:layout_weight="1000"        />    <EditText        android:id="@+id/et_path"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:hint="请输入图片的路径"        android:text="http://pic.58pic.com/58pic/16/62/63/97m58PICyWM_1024.jpg"        android:singleLine="true" />    <Button        android:text="浏览"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:onClick="click"/></LinearLayout>

在MainActivity中

package cn.edu.bzu.imageview;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.text.TextUtils;import android.view.View;import android.widget.EditText;import android.widget.ImageView;import android.widget.Toast;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;public class MainActivity extends Activity {    protected static final int CHANGE_UI = 1;    protected static final int ERROR = 2;    private EditText et_path;    private ImageView iv;    private Handler handler = new Handler() {        public void handleMessage(Message msg) {            if (msg.what == CHANGE_UI) {                Bitmap bitmap = (Bitmap) msg.obj;                iv.setImageBitmap(bitmap);            } else if (msg.what == ERROR) {                Toast.makeText(MainActivity.this, "显示图片错误",Toast.LENGTH_SHORT).show();            }        }        ;    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        et_path = (EditText) findViewById(R.id.et_path);        iv = (ImageView) findViewById(R.id.iv);    }    public void click(View view) {        final String path = et_path.getText().toString().trim();        if (TextUtils.isEmpty(path)) {            Toast.makeText(this, "图片路径不能为空", Toast.LENGTH_SHORT).show();        } else {//子线程请求网络，android4.0以后访问网络不能放在主线程中            new Thread() {                private HttpURLConnection conn;                private Bitmap bitmap;                public void run() {//连接服务器get请求，获取图片                    //创建URL对象                    try {                        URL url = new URL(path);                        conn = (HttpURLConnection) url.openConnection();//根据url发送http的请求                        conn.setRequestMethod("GET");//设置请求的方式                        conn.setConnectTimeout(5000);//设置超时时间                        conn.setRequestProperty("User-Agent", "Mozilla/4.0(compatible;MSIE 6.0;Windows NT 5.1;" + "SV1;.NET4.0C;.NET4.0E;.NET CLR 2.0.50727;" + ".NET CLR 3.0.4506.2152;.NET CLR 3.5.30729;Shuame)");//设置浏览器的版本                        int code = conn.getResponseCode();//得到服务器返回的响应码                        if (code == 200) {//请求成功后返回码是200                            InputStream is = conn.getInputStream();                            bitmap = BitmapFactory.decodeStream(is);                            Message msg = new Message();                            msg.what = CHANGE_UI;                            msg.obj = bitmap;                            handler.sendMessage(msg);                        } else {                            Message msg = new Message();                            msg.what = ERROR;                            handler.sendMessage(msg);                        }                    } catch (java.io.IOException e) {                        e.printStackTrace();                        Message msg = new Message();                        msg.what = ERROR;                        handler.sendMessage(msg);                    }                }            }.start();        }  }

package cn.edu.bzu.imageview;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.text.TextUtils;import android.view.View;import android.widget.EditText;import android.widget.ImageView;import android.widget.Toast;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;public class MainActivity extends Activity {    protected static final int CHANGE_UI = 1;    protected static final int ERROR = 2;    private EditText et_path;    private ImageView iv;    private Handler handler = new Handler() {        public void handleMessage(Message msg) {            if (msg.what == CHANGE_UI) {                Bitmap bitmap = (Bitmap) msg.obj;                iv.setImageBitmap(bitmap);            } else if (msg.what == ERROR) {                Toast.makeText(MainActivity.this, "显示图片错误",Toast.LENGTH_SHORT).show();            }        }        ;    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        et_path = (EditText) findViewById(R.id.et_path);        iv = (ImageView) findViewById(R.id.iv);    }    public void click(View view) {        final String path = et_path.getText().toString().trim();        if (TextUtils.isEmpty(path)) {            Toast.makeText(this, "图片路径不能为空", Toast.LENGTH_SHORT).show();        } else {
//子线程请求网络，android4.0以后访问网络不能放在主线程中            new Thread() {                private HttpURLConnection conn;                private Bitmap bitmap;                public void run() {//连接服务器get请求，获取图片                    //创建URL对象                    try {                        URL url = new URL(path);                        conn = (HttpURLConnection) url.openConnection();//根据url发送http的请求                        conn.setRequestMethod("GET");//设置请求的方式                        conn.setConnectTimeout(5000);//设置超时时间                        conn.setRequestProperty("User-Agent", "Mozilla/4.0(compatible;MSIE 6.0;Windows NT 5.1;" + "SV1;.NET4.0C;.NET4.0E;.NET CLR 2.0.50727;" + ".NET CLR 3.0.4506.2152;.NET CLR 3.5.30729;Shuame)");//设置浏览器的版本                        int code = conn.getResponseCode();//得到服务器返回的响应码                        if (code == 200) {//请求成功后返回码是200                            InputStream is = conn.getInputStream();                            bitmap = BitmapFactory.decodeStream(is);                            Message msg = new Message();                            msg.what = CHANGE_UI;                            msg.obj = bitmap;                            handler.sendMessage(msg);                        } else {                            Message msg = new Message();                            msg.what = ERROR;                            handler.sendMessage(msg);                        }                    } catch (java.io.IOException e) {                        e.printStackTrace();                        Message msg = new Message();                        msg.what = ERROR;                        handler.sendMessage(msg);                    }                }            }.start();        }  }
最后就是填权限，网络浏览器需要请求网络，需要在清单文件中添加权限
<uses-permission android:name="android.permission.INTERNET"</user-permission>