这是我的main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView android:id="@android:id/list" android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
这是我的清单。
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.jv.connection">
<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="com.jv.dataevent.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
这是我的MainActivity。
package com.jv.dataevent;
import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import com.jv.connection.R;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
public class MainActivity extends ListActivity {
/**
* Called when the activity is first created.
*/
@SuppressWarnings("unchecked")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_main);
setListAdapter(new ArrayAdapter(
this, android.R.layout.simple_list_item_1,
this.populate()));
}
private ArrayList populate() {
ArrayList items = new ArrayList();
try {
URL url = new URL("http://10.0.2.2/food.php");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("POST");
urlConnection.connect();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(
urlConnection.getInputStream()));
String next;
while ((next = bufferedReader.readLine()) != null) {
JSONArray ja = new JSONArray(next);
for (int i = 0; i < ja.length(); i++) {
JSONObject jo = (JSONObject) ja.get(i);
items.add(jo.getString("food_id"));
items.add(jo.getString("food_name"));
}
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return items;
}
}
我想将我的Android应用程序连接到数据库并在列表项中读取它。 当我将它播放到模拟器时，它显示不幸的是，myapp已停止。并显示此错误
01-18 12:20:08.188 27841-27841/com.jv.dataevent E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.jv.dataevent, PID: 27841
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jv.dataevent/com.jv.dataevent.MainActivity}: android.os.NetworkOnMainThreadException
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$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1145)
at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
at libcore.io.IoBridge.connect(IoBridge.java:112)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
at java.net.Socket.connect(Socket.java:843)
at com.android.okhttp.internal.Platform.connectSocket(Platform.java:131)
at com.android.okhttp.Connection.connect(Connection.java:101)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:294)
at com.android.okhttp.internal.http.HttpEngine.sendSocketRequest(HttpEngine.java:255)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:206)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:345)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:89)
at com.jv.dataevent.MainActivity.populate(MainActivity.java:44)
at com.jv.dataevent.MainActivity.onCreate(MainActivity.java:32)
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)
感谢有人在这里帮助我。
答案 0 :(得分：0)
尝试在主线程上执行网络操作时抛出NetworkOnMainThreadException
见：
http://developer.android.com/reference/android/os/NetworkOnMainThreadException.html
为网络操作创建新线程或在服务中运行。
答案 1 :(得分：-1)
您正在尝试访问网络主线程，这是Android 3.0禁止的。
要解决此问题，您需要使用AsyncTask