我试图运行这个简单的JSON解析程序，但它向我显示以下错误。我是Android Studio新手。
我不知道该怎么做以及如何解决它，我读了很多答案，但我找不到解决方案。
Process: com.dropouts.jsondemo, PID: 1126
java.lang.RuntimeException: Unabl``e to start activity ComponentInfo{com.dropouts.jsondemo/com.dropouts.jsondemo.MainActivity}: java.lang.SecurityException: ConnectivityService: Neither user 10053 nor current process has android.permission.ACCESS_NETWORK_STATE.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.SecurityException: ConnectivityService: Neither user 10053 nor current process has android.permission.ACCESS_NETWORK_STATE.
at android.os.Parcel.readException(Parcel.java:1472)
at android.os.Parcel.readException(Parcel.java:1426)
at android.net.IConnectivityManager$Stub$Proxy.getActiveNetworkInfo(IConnectivityManager.java:817)
at android.net.ConnectivityManager.getActiveNetworkInfo(ConnectivityManager.java:562)
at com.dropouts.jsondemo.MainActivity.isConnected(MainActivity.java:88)
at com.dropouts.jsondemo.MainActivity.onCreate(MainActivity.java:35)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
这是我的mainactivity.java
MAINACTIVITY.JAVA
package com.dropouts.jsondemo;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.app.Activity;
public class MainActivity extends Activity {
EditText etResponse;
TextView tvIsConnected;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// get reference to the views
etResponse = (EditText) findViewById(R.id.etResponse);
tvIsConnected = (TextView) findViewById(R.id.tvIsConnected);
// check if you are connected or not
if(isConnected()){
tvIsConnected.setBackgroundColor(0xFF00CC00);
tvIsConnected.setText("You are conncted");
}
else{
tvIsConnected.setText("You are NOT conncted");
}
// call AsynTask to perform network operation on separate thread
new HttpAsyncTask().execute("http://hmkcode.appspot.com/rest/controller/get.json");
}
public static String GET(String url){
InputStream inputStream = null;
String result = "";
try {
// create HttpClient
HttpClient httpclient = new DefaultHttpClient();
// make GET request to the given URL
HttpResponse httpResponse = httpclient.execute(new HttpGet(url));
// receive response as inputStream
inputStream = httpResponse.getEntity().getContent();
// convert inputstream to string
if(inputStream != null)
result = convertInputStreamToString(inputStream);
else
result = "Did not work!";
} catch (Exception e) {
Log.d("InputStream", e.getLocalizedMessage());
}
return result;
}
private static String convertInputStreamToString(InputStream inputStream) throws IOException{
BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
String line = "";
String result = "";
while((line = bufferedReader.readLine()) != null)
result += line;
inputStream.close();
return result;
}
public boolean isConnected(){
ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Activity.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected())
return true;
else
return false;
}
private class HttpAsyncTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {
return GET(urls[0]);
}
// onPostExecute displays the results of the AsyncTask.
@Override
protected void onPostExecute(String result) {
Toast.makeText(getBaseContext(), "Received!", Toast.LENGTH_LONG).show();
etResponse.setText(result);
}
}
}
以下是我的manifest.xml文件
的Manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.dropouts.jsondemo">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
是我的activitymain xml文件
activitymain.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/tvIsConnected"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:background="#FF0000"
android:textColor="#FFF"
android:textSize="18dp"
android:layout_marginBottom="5dp"
android:text="is connected? " />
<EditText
android:id="@+id/etResponse"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:ems="10"
android:layout_marginTop="10dp"
android:inputType="textMultiLine" >\
<requestFocus />
</EditText>
</LinearLayout>
答案 0 :(得分：1)
根据堆栈跟踪，您需要请求android.permission.ACCESS_NETWORK_STATE权限。
此链接应说明您的需求： http://developer.android.com/training/permissions/requesting.html
答案 1 :(得分：0)
您应该两次添加权限。
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>