Android获取网页源码

Question

我想获取用户输入的网页的源代码。当他按下按钮时，他应该会在

TextView

中看到源。这是我的代码：

final Button b = (Button) findViewById(R.id.button1);

        b.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub

                try {
                    URL url = null;
                    url = new URL(myEditText.getText().toString());
                    URLConnection conn = url.openConnection();
                    BufferedReader reader = new BufferedReader(
                            new InputStreamReader(conn.getInputStream()));
                    String line = "";
                    while ((line = reader.readLine()) != null) {
                        myTextView.append(line);

                    }

                } catch (Exception e) {

                    Log.e("ERR",e.getMessage());
                }

            }
        });

当我运行它时，我在

处收到 NullPointerException

BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream())); 

.-->Println 需要一条消息。

我不知道出了什么问题，因为这是来自视频教程。我已经在清单中写了

<uses-permission android:name="android.permission.INTERNET"/>

，所以一切都应该没问题。

Answer 1

试试这个。

url = new URL("http://www.stackoverflow.com");

如果它有效，那么您需要设置验证，例如 isValidUrl() ?

因为用户可能输入了错误的网址。

Answer 2

    if(!TextUtils.isEmpty(myEditText.getText()))
             url = new URL(myEditText.getText().toString());
else
url="";

或者如果您使用的是最新版本，请检查 StrictMode 并将其删除

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);

还要检查 Android 是否有网络可用

Answer 3

我的解决方案是用javascript修改onPageFinished以显示html源代码。

        webview1.setWebViewClient(new WebViewClient() {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {     /* web links should open within app, not the external browser */
            view.loadUrl(url);
            return true;
        }


        @Override
        public void onPageFinished(WebView view, String url) {
            view.loadUrl("javascript:" +

                    "function get_doctype() { var doctype = '<!DOCTYPE ' + document.doctype.name + (document.doctype.publicId?' PUBLIC \"' + document.doctype.publicId + '\"':'') + (document.doctype.systemId?' \"' + document.doctype.systemId + '\"':'') + '>'; return doctype; } \n" +
                    "" +
                    "var a1 = get_doctype() + document.documentElement.outerHTML; " +
                    "    a1 = a1.replaceAll(\"<\", \"&lt;\").replaceAll(\">\", \"&gt;\").replaceAll(\"\\n\", \"<br>\"); " +
                    "" +
                    "var href = window.location.href;" +
                    "" +
                    "page_load = function() {" +
                    "    window.location.href = href;" +
                    "};" +
                    "" +
                    "view_html = function() {" +
                    "$('body').html('<center><button onclick=\"page_load()\">Go To Page</button></center><pre style=\"font-weight:bold;font-size:85%;padding-left:5px;\">'+ a1 + '</pre>');" +
                    "};" +
                    "" +
                    "$('body').append('<span id=\"html_source_code\"></span><br><button style=\"position:absolute;bottom:0px;left:0px;z-index:800;\" onclick=\"view_html();\">View HTML Source Code</button><br>'); " +
                    "" +
                    ""
            );
        }
    });

谢谢您，请投票支持这个答案。