Question

package com.nitrr.nrnotifier;

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;


import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.utils.URLEncodedUtils;
 import org.apache.http.impl.client.DefaultHttpClient;
 import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

 import android.app.Activity;
 import android.content.Intent;
 import android.net.ParseException;
 import android.net.Uri;
 import android.os.Bundle;
 import android.util.Log;
 import android.webkit.MimeTypeMap;
 import android.widget.Toast;

public class Act3 extends Activity
{
 static InputStream is = null;
 String result = null;
  public void onCreate(Bundle savedInstanceState)
  {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.third);
        String id=getIntent().getExtras().getString("pid");
        try
        {
             List<NameValuePair> params = new ArrayList<NameValuePair>();
             params.add(new BasicNameValuePair("id", id));
            DefaultHttpClient httpClient = new DefaultHttpClient();
            String paramString = URLEncodedUtils.format(params, "utf-8");
            String url="http://10.0.2.2/ndesc.php";
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
        }
        catch(Exception se){
            Log.e("log_tag", "Error in http connection"+se.toString());
        }

        //convert response to string
        try{

        BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
              StringBuilder sb = new StringBuilder();
            sb.append(reader.readLine() + "\n");
            String line="0";

            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }

            is.close();
            result = sb.toString();
           System.out.println(result);

        }catch(Exception e){
            Log.e("log_tag", "Error converting result "+e.toString());
        }




        try{
            JSONArray jArray = new JSONArray(result);
            JSONObject json_data = null;

            for(int i = 0; i < jArray.length(); i++){
                    json_data = jArray.getJSONObject(i);
                   String filepath=json_data.getString("ndesc");
                   Uri fileUri = Uri.fromFile(new File(filepath));

                   Uri new_uri = Uri.parse("file://"
                           + fileUri.getPath());

                   Intent intent = new Intent(Intent.ACTION_VIEW,
                           new_uri);

                   MimeTypeMap myMime = MimeTypeMap.getSingleton();
                   String fileExt = filepath.substring(filepath
                           .lastIndexOf(".") + 1);
                   String mimeType = myMime
                           .getMimeTypeFromExtension(fileExt);
                   intent.setDataAndType(new_uri, mimeType);

                   startActivity(intent);



            }

            }catch(JSONException e2)
            {  e2.printStackTrace();
                Toast.makeText(getBaseContext(), "No User Found", Toast.LENGTH_LONG).show();
            }catch (ParseException e1){
                e1.printStackTrace();
            } 
 }


}

这是我的代码，我从服务器数据库I文件类型变量存储获取的文件路径，然后处理它。但是我无法得到我预期的输出，即文件本身......代码抛出异常我得到了

没有android.content.ActivityNotFoundException：找不到任何活动处理Intent {act = android.intent.action.VIEW dat = file：/// http：/127.0.0.1/45_Hindi Theme 1＆amp; 2（第IX类）.pdf typ = application / pdf}

请帮我解决这个问题。

Answer 1

此错误很简单，您的设备没有任何响应意图的应用程序。

您应该处理异常并告诉用户他在设备上有任何PDF阅读器。

Answer 2

你需要将该代码移动到AsyncTask类中，因为你不能在主线程上调用互联网连接。

所以将所有这些代码移到某个函数中，比如getPdf（）;

并粘贴此

        new AsyncTask<Void, Void, Void>(){


        @Override
        protected Void doInBackground(Void... params) {
            getPdf();
            return null;
        }
    }.execute();

并且您还需要AndroidManifest.xml文件中的互联网权限

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

ActivityNotFoundException：找不到处理Intent的Activity {act = android.intent.action.VIEW

2 个答案: