博客

1.解析网站并显示

因为要处理网页读取，需要开启线程，并在UI上更新，则要使用handler

注意Handler导入的是os包

下面是MainActivity

private WebView webView;
    private WebView webView;
    private Handler handler=new Handler();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_http_url_connection);
        webView=(WebView)findViewById(R.id.webview);
        
        new HttpThread("http://www.baidu.com",handler,webView).start();
        
    }

子线程类

public class HttpThread extends Thread {
    private String url=null;
    private Handler handler;
    private WebView webView;
    StringBuffer sb;

    public HttpThread(String url,Handler handler,WebView webView){
        this.url=url;
        this.handler=handler;
        this.webView=webView;
    }

    @Override
    public void run() {

        try {
            //获取URL对象
            URL httpUrl=new URL(url);
            //通过URL对象获取连接
            HttpURLConnection conn= (HttpURLConnection) httpUrl.openConnection();
            //设置 连接读取时长
            conn.setReadTimeout(5000);
            //设置以get形式请求
            conn.setRequestMethod("GET");
            //字符串流
            sb=new StringBuffer();
            //获得连接的字节输入流
            InputStream is=conn.getInputStream();
            //将字节输入流转换为字符输入流
            InputStreamReader isr=new InputStreamReader(is);
            //加载到缓存流中,只有缓存流可以直接读一行
            BufferedReader reader=new BufferedReader(isr);
            String str;
            while ((str=reader.readLine())!=null){
                sb.append(str);
            }

            //使用post(),在runable中更新UI
            handler.post(new Runnable() {
                @Override
                public void run() {
                   webView.loadData(sb.toString(),"text/html;charset=utf-8",null);
                }
            });


        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

2.解析图片网址，先保存在外部存储中，在通过bitmap获取到UI中

在MainActivity中开启线程

下面的网址一定要是一个图片网址，即后缀以,jpg或其他图片格式显示

new HttpThread("http://pic.sc.chinaz.com/files/pic/pic9/201512/apic17727.jpg",handler,imageView).start();

子线程类

public class HttpThread extends Thread {
    private String url=null;
    private Handler handler;
    private ImageView imageView;


    public HttpThread(String url,Handler handler,ImageView imageView){
        this.url=url;
        this.handler=handler;
        this.imageView=imageView;
    }

    @Override
    public void run() {
        try {
            URL httpUrl=new URL(url);
            //通过URL对象获取连接
            HttpURLConnection conn= (HttpURLConnection) httpUrl.openConnection();
            //设置 连接读取时长
            conn.setReadTimeout(5000);
            //设置以get形式请求
            conn.setRequestMethod("GET");
            //文档上只是写着设置连接允许输入，不知道是什么意思
            conn.setDoInput(true);
            InputStream in=conn.getInputStream();
            FileOutputStream out=null;
            File downloadFile=null;

            Log.i("info","进入到HttpThread中");
            String fileName=String.valueOf(System.currentTimeMillis());
            //只有在SD卡状态为MEDIA_MOUNTED时,/mmt/sdcard目录才是可读可写的，并且可以创建目录及文件
            if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {

                //获取外部存储路径，外部存储不一定是sd卡，还包括手机自带的内存，内部存储是指data/data/包名下的
                File parent=Environment.getExternalStorageDirectory();
                //在获取的目录下新建文件名为fileName的文件
                downloadFile=new File(parent,fileName);
                //文件输出流
                out=new FileOutputStream(downloadFile);

            }
            byte[] b=new byte[2*1024];
            int len;

            if(out!=null){
                //通过字节流的读取方法，以数组为缓存
                while((len=in.read(b))!=-1){
                    out.write(b,0,len);
                }

            }

            //通过指定sd卡图片文件路径来获取bitmap
            final Bitmap bitmap= BitmapFactory.decodeFile(downloadFile.getAbsolutePath());
            handler.post(new Runnable() {
                @Override
                public void run() {
                    Log.i("info","写入成功");
                    imageView.setImageBitmap(bitmap);
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

上面获取网页图片是先存到外部存储中，然后在将图片从外部存储中取出来，当然可以直接通过网页来获取，下面的代码只是将获取的方式从文件改为了流

URL httpUrl=new URL(url);
            HttpURLConnection connection=(HttpURLConnection)httpUrl.openConnection();
            connection.setReadTimeout(5000);
            connection.setRequestMethod("GET");
            InputStream in=connection.getInputStream();
            //通过获取网上的输入流，来将图片传给Bitmap
            final Bitmap bitmap= BitmapFactory.decodeStream(in);

            //同样通过post更新UI
            handler.post(new Runnable() {
                @Override
                public void run() {
                    imageView.setImageBitmap(bitmap);
                }
            });