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>