我使用Google Directions API来获取位置之间的时间，我试图将URL中的数据转换为JSON对象，以便我可以解析它以获取所需的数据。网址是：
我使用意图转到此网址。
String url = "http://maps.googleapis.com/maps/api/directions/json?origin=Chicago,IL&destination=Los+Angeles,CA&waypoints=Joplin,MO|Oklahoma+City,OK&sensor=false"
Intent intent = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse(url));
startActivity(intent);
这会在浏览器中显示json数据，我想把它放到一个json对象中，这样我就可以得到我需要的任何数据：
JSONObject durationObject = null;
durationObject = jsonObject.getJSONObject("duration");
我已经在网上看了这个，但我尝试的所有内容都会崩溃或无法正常工作。 下面是我尝试但不起作用的一些代码。由于if语句的执行，所以最终都没有写入String结果。
InputStream is = null;
String result = "";
JSONObject jsonObject = null;
try {
HttpClient httpclient = new DefaultHttpClient(); // for port 80 requests!
HttpPost httppost = new HttpPost(url);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
// Read response to string
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"utf-8"),1024);
StringBuilder sb = new StringBuilder();
String line = "";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
if (result.isEmpty()) {
result = "nothing";
Toast msg = Toast.makeText(getBaseContext(), result, Toast.LENGTH_LONG);
msg.show();
}
// Convert string to object
jsonObject = new JSONObject(result);
这是logcat输出：
04-16 18:38:42.965: W/dalvikvm(9331): threadid=1: thread exiting with uncaught exception (group=0x40c371f8)
04-16 18:38:42.975: E/AndroidRuntime(9331): FATAL EXCEPTION: main
04-16 18:38:42.975: E/AndroidRuntime(9331): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test/com.example.test.MainActivity}: android.os.NetworkOnMainThreadException
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1968)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1993)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.ActivityThread.access$600(ActivityThread.java:127)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1159)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.os.Handler.dispatchMessage(Handler.java:99)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.os.Looper.loop(Looper.java:137)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.ActivityThread.main(ActivityThread.java:4507)
04-16 18:38:42.975: E/AndroidRuntime(9331): at java.lang.reflect.Method.invokeNative(Native Method)
04-16 18:38:42.975: E/AndroidRuntime(9331): at java.lang.reflect.Method.invoke(Method.java:511)
04-16 18:38:42.975: E/AndroidRuntime(9331): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
04-16 18:38:42.975: E/AndroidRuntime(9331): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
04-16 18:38:42.975: E/AndroidRuntime(9331): at dalvik.system.NativeStart.main(Native Method)
04-16 18:38:42.975: E/AndroidRuntime(9331): Caused by: android.os.NetworkOnMainThreadException
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
04-16 18:38:42.975: E/AndroidRuntime(9331): at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
04-16 18:38:42.975: E/AndroidRuntime(9331): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
04-16 18:38:42.975: E/AndroidRuntime(9331): at java.net.InetAddress.getAllByName(InetAddress.java:220)
04-16 18:38:42.975: E/AndroidRuntime(9331): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
04-16 18:38:42.975: E/AndroidRuntime(9331): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
04-16 18:38:42.975: E/AndroidRuntime(9331): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
04-16 18:38:42.975: E/AndroidRuntime(9331): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
04-16 18:38:42.975: E/AndroidRuntime(9331): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
04-16 18:38:42.975: E/AndroidRuntime(9331): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
04-16 18:38:42.975: E/AndroidRuntime(9331): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
04-16 18:38:42.975: E/AndroidRuntime(9331): at com.example.test.MainActivity.onCreate(MainActivity.java:93)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.Activity.performCreate(Activity.java:4465)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1052)
04-16 18:38:42.975: E/AndroidRuntime(9331): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1932)
04-16 18:38:42.975: E/AndroidRuntime(9331): ... 11 more
我正在研究它，它似乎与启用严格模式有关。如何解决这个问题的任何帮助都会很棒。
答案 0 :(得分：0)
这是我正在使用的工作代码
private DefaultHttpClient httpclient = new DefaultHttpClient();
public JSONObject getObjectInfo(String requestURL) throws Exception {
JSONObject responseObject = null;
Log.d(getClass().getSimpleName(), "HttpClient: getObjectInfo: "
+ requestURL);
HttpGet httpget = new HttpGet(requestURL);
HttpResponse response;
try {
response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
Log.d(getClass().getSimpleName(), "HttpClient: getObjectInfo: "
+ "respondreceived");
if (entity != null) {
InputStream instream = entity.getContent();
Log.d("httpclient",
"HttpClient: getObjectInfo: converting to string");
String jsonObjectString = Conversion
.convertStreamToString(instream);
try {
responseObject = new JSONObject(jsonObjectString);
} catch (JSONException e) {
e.printStackTrace();
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (IllegalStateException e1) {
e1.printStackTrace();
} finally {
}
return responseObject;
}
将流转换为字符串的方法：
public static String convertStreamToString(java.io.InputStream is) {
try {
return new java.util.Scanner(is).useDelimiter("\\A").next();
} catch (java.util.NoSuchElementException e) {
return "";
}
}
说，我建议使用Jakson库从收到的json对象创建一个类。 here是如何使用Jakson库的示例。
答案 1 :(得分：0)
这里发生的事情很常见，您正试图在应用程序的主线程上执行一些长时间运行的操作。
这意味着，主线程负责更新UI，以实现流畅的体验，如果android检测到你正在做一些长时间运行的操作，它会阻塞，它会强制关闭应用程序，让你知道这很糟糕。
有许多替代解决方案，例如AsynTask或IntentService。
IntentService是一种在您向其发送意图时运行的服务：
public class NetworkHandler extends IntentService {
@Override
protected void onHandleIntent(Intent intent) {
//Do what Saeid Farivar is saying here
}
}
要激活IntentService，只需执行以下操作：
Intent intent = new Intent(mContext, NetworkHandler.class);
startService(intent);