我有一个我正在构建的应用程序，它使用操作栏搜索将搜索词发送到在线api，后者发送回json结果。
到目前为止，我已经进行了搜索工作，并对json解析器进行了编码以查看结果。我还没有在列表视图中显示结果。
当我尝试使用api请求和json解析器进行搜索时，我会收到一个强制关闭。
Log Cat：
06-04 20:23:15.542: D/libEGL(31832): loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so
06-04 20:23:15.558: D/libEGL(31832): loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so
06-04 20:23:15.566: D/libEGL(31832): loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
06-04 20:23:15.667: D/OpenGLRenderer(31832): Enabling debug mode 0
06-04 20:23:20.386: E/SpannableStringBuilder(31832): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
06-04 20:23:20.386: E/SpannableStringBuilder(31832): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
06-04 20:23:20.472: E/SpannableStringBuilder(31832): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
06-04 20:23:20.472: E/SpannableStringBuilder(31832): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
06-04 20:23:27.120: D/AndroidRuntime(31832): Shutting down VM
06-04 20:23:27.120: W/dalvikvm(31832): threadid=1: thread exiting with uncaught exception (group=0x4121c930)
06-04 20:23:27.144: E/AndroidRuntime(31832): FATAL EXCEPTION: main
06-04 20:23:27.144: E/AndroidRuntime(31832): android.os.NetworkOnMainThreadException
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
06-04 20:23:27.144: E/AndroidRuntime(31832): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
06-04 20:23:27.144: E/AndroidRuntime(31832): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
06-04 20:23:27.144: E/AndroidRuntime(31832): at java.net.InetAddress.getAllByName(InetAddress.java:214)
06-04 20:23:27.144: E/AndroidRuntime(31832): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
06-04 20:23:27.144: E/AndroidRuntime(31832): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
06-04 20:23:27.144: E/AndroidRuntime(31832): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
06-04 20:23:27.144: E/AndroidRuntime(31832): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
06-04 20:23:27.144: E/AndroidRuntime(31832): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
06-04 20:23:27.144: E/AndroidRuntime(31832): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
06-04 20:23:27.144: E/AndroidRuntime(31832): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
06-04 20:23:27.144: E/AndroidRuntime(31832): at com.example.beerportfoliopro.JSONParser.getJSONFromUrl(JSONParser.java:38)
06-04 20:23:27.144: E/AndroidRuntime(31832): at com.example.beerportfoliopro.MainActivity.onQueryTextSubmit(MainActivity.java:53)
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.widget.SearchView.onSubmitQuery(SearchView.java:1161)
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.widget.SearchView.access$900(SearchView.java:92)
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.widget.SearchView$8.onEditorAction(SearchView.java:1139)
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.widget.TextView.onEditorAction(TextView.java:4117)
06-04 20:23:27.144: E/AndroidRuntime(31832): at com.android.internal.widget.EditableInputConnection.performEditorAction(EditableInputConnection.java:138)
06-04 20:23:27.144: E/AndroidRuntime(31832): at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:297)
06-04 20:23:27.144: E/AndroidRuntime(31832): at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:77)
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.os.Handler.dispatchMessage(Handler.java:99)
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.os.Looper.loop(Looper.java:137)
06-04 20:23:27.144: E/AndroidRuntime(31832): at android.app.ActivityThread.main(ActivityThread.java:5226)
06-04 20:23:27.144: E/AndroidRuntime(31832): at java.lang.reflect.Method.invokeNative(Native Method)
06-04 20:23:27.144: E/AndroidRuntime(31832): at java.lang.reflect.Method.invoke(Method.java:511)
06-04 20:23:27.144: E/AndroidRuntime(31832): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
06-04 20:23:27.144: E/AndroidRuntime(31832): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
06-04 20:23:27.144: E/AndroidRuntime(31832): at dalvik.system.NativeStart.main(Native Method)
API请求和JSON解析
url = url + query;
Toast.makeText(this, url, Toast.LENGTH_SHORT).show();
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
// Getting Array of beers
try {
JSONArray beers = json.getJSONArray("data");
// looping through All beers
for(int i = 0; i < beers.length(); i++){
JSONObject c = beers.getJSONObject(i);
//get beer information
String beerID = c.getString("id");
String beerName = c.getString("name");
String beerDescription = c.getString("description");
String beerABV = c.getString("abv");
String beerIBU = c.getString("ibu");
}
}
catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
JSONParser.java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
答案 0 :(得分：2)
你应该检查printStack
android.os.NetworkOnMainThreadException
您的问题是，从Exception的名称看起来很明显，您不应该从UI Thread发出网络请求。
在android文档中查看AsyncTask。
答案 1 :(得分：2)
执行至少在另一个线程上发出请求的代码。最简单的方法是使用AsyncTask。
final String jsonUrl = url + query;
Toast.makeText(this, jsonUrl, Toast.LENGTH_SHORT).show();
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... voids) {
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
// Getting Array of beers
try {
JSONArray beers = json.getJSONArray("data");
// looping through All beers
for(int i = 0; i < beers.length(); i++){
JSONObject c = beers.getJSONObject(i);
//get beer information
String beerID = c.getString("id");
String beerName = c.getString("name");
String beerDescription = c.getString("description");
String beerABV = c.getString("abv");
String beerIBU = c.getString("ibu");
}
}
catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}.execute();
答案 2 :(得分：0)
看起来像是StrictMode异常。您不应该在UI线程上执行任何类型的网络操作（任何操作都来自活动上下文，除非明确地放在另一个线程上），因此您需要使用Android-y之类的方法来执行此操作这，AsyncTask。
http://developer.android.com/training/articles/perf-anr.html
http://developer.android.com/reference/android/os/AsyncTask.html