java - 将数据从 Android 应用发布到 PHP 页面

Question

我一直在查看其他几篇文章，并尝试组合一种方法将数据从我的 Android 应用程序发布到我们网站上的 php 页面。基本上，这是一个域名检查功能，我希望用户能够在应用程序中输入域名，然后当他们单击“立即检查”时，他们会进入网页并显示结果。我目前并不担心在应用程序中显示结果。

这是我到目前为止的代码:

public class Domain_check extends Activity {

public void onCreate(Bundle savedInstanceState) {
    postData();
}

public void postData() {
    EditText domainText = (EditText) findViewById(R.id.hosting_link);
    if (domainText.length()>0)
    {
        // Create a new HttpClient and Post Header
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("https://www.oursite.com/domainchecker.php");



        try {
            // Add your data
            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
            nameValuePairs.add(new BasicNameValuePair("id",domainText.getText().toString()));
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

            // Execute HTTP Post Request
            httpclient.execute(httppost);

        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        } catch (IOException e) {
            // TODO Auto-generated catch block
        }
    }
    else
    {
        // display message if text fields are empty
        Toast.makeText(getBaseContext(),"Please enter a domain name",Toast.LENGTH_SHORT).show();
    }

} 

目前，当我单击按钮进行检查(运行此 Activity )时，我收到 nullPointerError。

我对 Java 还很陌生，所以这可能是一种更简单的方法!

谢谢

编辑:

错误:

01-18 11:05:39.720: E/AndroidRuntime(353): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.oursite/com.oursite.Domain_check}: java.lang.NullPointerException

修改了代码，代码现在位于绘制输入文本的 View 的 Activity 中，而不是单独的 Activity 中:

public class Hosting extends Activity implements OnClickListener {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.hosting);

   View DomainButton = findViewById(R.id.domain_button);
   DomainButton.setOnClickListener((OnClickListener) this);     
}

public void onClick (View thisView) {
    postData();
}

public void postData() {
    EditText domainText = (EditText) findViewById(R.id.hosting_link);
    if (domainText.length()>0)
    {
        // Create a new HttpClient and Post Header
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("https://www.oursite.com/domainchecker.php");



        try {
            // Add your data
            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
            nameValuePairs.add(new BasicNameValuePair("id",domainText.getText().toString()));
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

            // Execute HTTP Post Request
            httpclient.execute(httppost);

        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        } catch (IOException e) {
            // TODO Auto-generated catch block
        }
    }
    else
    {
        // display message if text fields are empty
        Toast.makeText(getBaseContext(),"Please enter a domain name",Toast.LENGTH_SHORT).show();
    }
}

}

Answer 1

我在您的 Activity 中没有看到 setContentView() 方法。因此，当您尝试获取长度时，domainText 变量为 null