Question

从android向PHP MySql插入6列，显示这3个错误使用Fragment实现App /代码，此代码在其中一个片段文件上完成。在Manifest中也添加了Internet权限

Log Cat

06-23 00:52:53.830: E/Fail 1(1512):android.os.NetworkOnMainThreadException
06-23 00:52:53.830: E/Fail 2(1512):java.lang.NullPointerException:lock==null
06-23 00:52:53.830: E/Fail 3(1512):java.lang.NullPointerException

Android代码

    submit.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        addque = question.getText().toString();
        addc1 = choice1.getText().toString();
        addc2 = choice2.getText().toString();
        addc3 = choice3.getText().toString();
        addanswer = answer.getText().toString();
        addexplan = Explanation.getText().toString();
        insert();
        //Toast.makeText(getActivity(), "Question posted", Toast.LENGTH_SHORT).show();

    }
});

将函数插入同一文件

    public void insert() {
    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

    nameValuePairs.add(new BasicNameValuePair("addque", addque));
    nameValuePairs.add(new BasicNameValuePair("addc1", addc1));
    nameValuePairs.add(new BasicNameValuePair("addc2", addc2));
    nameValuePairs.add(new BasicNameValuePair("addc3", addc3));
    nameValuePairs.add(new BasicNameValuePair("addanswer", addanswer));
    nameValuePairs.add(new BasicNameValuePair("addexplan", addexplan));

    try {
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new
                HttpPost("http://localhost/insert/insert.php");
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();
        Log.e("pass 1", "connection success ");
    } catch (Exception e) {
        Log.e("Fail 1", e.toString());
        //Toast.makeText(getApplicationContext(), "Invalid IP 
        Address ",Toast.LENGTH_LONG).show();
    }

    try {
        BufferedReader reader = new BufferedReader
                (new InputStreamReader(is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        result = sb.toString();
        Log.e("pass 2", "connection success ");
    } catch (Exception e) {
        Log.e("Fail 2", e.toString());
    }

    try {
        JSONObject json_data = new JSONObject(result);
        code = (json_data.getInt("code"));

        if (code == 1) {
            Toast.makeText(getActivity(), "Inserted Successfully",
                    Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(getActivity(), "Sorry, Try Again",
                    Toast.LENGTH_LONG).show();
        }
    } catch (Exception e) {
        Log.e("Fail 3", e.toString());
    }
}

Android中从Mysql中插入数据的新功能三江源

Answer 1

Android不允许在UI线程上进行任何网络操作，您需要创建单独的线程来执行此操作。您可以使用asynctask，如下所示：

class MyAsyncTask extends AsyncTask<Void,Void,Void> {

    @Override
    protected Void doInBackground(Void... params) {
        insert();
    }
}

Answer 2

您无法在主线程上调用网络操作，您必须创建执行操作的后台线程。

参考

1。 AsyncTask Documentation

2。 AsyncTask Example

Answer 3

您的stacktrace清楚地表明您正在从UI线程调用网络API。您应该使用后台线程或AsyncTask。

Answer 4

对于NetworkOnMainThreadException，你需要在后台线程上移动插入调用，这是由于

您无法在主线程上调用网络操作，您必须创建执行操作的后台线程。

，为此您需要使用AsyncTask

    AsyncTask.execute(new Runnable() {
        @Override
        public void run() {
            insert(); // call insert method in this block
                      // which is background thread, 
                      // prevents network call to run on MainThread                       
        }
    });

并且如果需要在插入方法调用的主线程上运行任何更新，runOnUiThread就像Toast一样，提醒。等

    runOnUiThread(new Runnable() {
        @Override
        public void run() {
            // Toast, Alerts or any operation that needs
            // to interact on UI, call here
        }
    });

如果您正在使用片段调用

 getActivity().runOnUiThread(new Runnable() {
        @Override
        public void run() {
            // Toast, Alerts or any operation that needs
            // to interact on UI, call here
        }
    });

PS：在实施之前，您需要清楚地了解这些主题，因此您必须浏览开发人员文档。

错误：从Android插入MySql中的数据时

4 个答案: