Android Httprequest无效

Question

我是新手在Android中，我想要一个网页并获得回复。我已经从一个教程编写了这段代码，虽然我写的完全一样，并且我已经在清单文件中给予了访问互联网的权限，它没有工作或没有返回任何东西。这是调用名为MainActivity.java的主要活动     package com.example.limon.myapplication;

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;


public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    TextView tv = (TextView) findViewById(R.id.txt1);

    WebResult web = new WebResult();
    String result = "";
    try {
        result = web.getResult();
    } catch (Exception e) {
        e.printStackTrace();
    }
    tv.setText(result);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

} ＆GT;

这是另一个返回响应的类

package com.example.limon.myapplication;

import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URL;

/**
 * Created by Limon on 3/11/2015.
 */
public class WebResult {

public String getResult() throws  Exception{
    BufferedReader in = null;
    String data = null;

    try{
        HttpClient client = new DefaultHttpClient();
        URI website = new URI("http://www.mybringback.com");
        HttpGet request = new HttpGet();
        request.setURI(website);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer sb = new StringBuffer("");
        String l = "";
        String nl = System.getProperty("line.separator");
        while( (l = in.readLine()) != null ){
            sb.append(l + nl);
        }
        in.close();
        data = sb.toString();
        return data;
    }
    finally {
        if(in != null){
            try{
                in.close();
                return data;
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

}

Answer 1

您是否在Android清单中添加了互联网权限？  <uses-permission android:name="android.permission.INTERNET" />

所有http请求都不能在主线程中使用。 阅读：AsyncTask

Answer 2

转到您的项目并打开AndroidManifest.xml并添加

等代码

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

允许与互联网进行互动

Answer 3

尝试将此属性添加到您的AndroidManifest.xml中，以允许所有HTTP请求：

android：usesCleartextTraffic =“ true”