工作bootstrapv4样式不正确

Question

我导入bootstrap文件：

public String makeHttpRequestJsonString(String path, int requestType, Map<String, String> params){
    String json = "";
    InputStream responseStream = null;

    try {
        startTime = System.currentTimeMillis();

        StringBuilder postData = new StringBuilder();
        for(Map.Entry<String, String> param : params.entrySet()){
            if(postData.length() != 0) postData.append('&');
            postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
            postData.append('=');
            postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
        }

        byte[] postDataBytes = postData.toString().getBytes("UTF-8");

        URL url = makeURL(path, requestType);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        conn.setUseCaches(false);
        conn.setDoOutput(true);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("Cache-Control", "no-cache");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length));

        DataOutputStream request = new DataOutputStream(conn.getOutputStream());
        request.write(postDataBytes);
        request.flush();
        //Some people have reported issues when closing the the request before reading the 
        request.close();

        //Check the response code of the server -
        Integer replyCode = conn.getResponseCode();
        //System.out.println("Reply Code:  " + replyCode.toString());

        responseStream = new BufferedInputStream(conn.getInputStream());
        BufferedReader responseStreamReader = new BufferedReader(new InputStreamReader(responseStream));

        String line = "";
        StringBuilder stringBuilder = new StringBuilder();

        while ((line = responseStreamReader.readLine()) != null) {
            stringBuilder.append(line).append("\n");
        }
        responseStreamReader.close();

        json = stringBuilder.toString();

    }
    catch (UnsupportedEncodingException e) {
    } catch (IOException e) {
        Log.e(TAG, "makeHttpRequestJsonString --- " + e.getMessage());
    }
    return json;
}

为链接添加html

import 'bootstrap/dist/css/bootstrap.min.css'
import 'bootstrap/dist/js/bootstrap.min.js'

并且有那个

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