我正在尝试将mysql生成的json文件解析到我的android应用程序中。屏幕根本不显示任何内容。我可以直接在浏览器中提取json文件并输出数据。我不确定为什么我在应用程序中看不到它。如果有人想看一下，我会在这里添加适用的代码。
logcat的
12-02 23:54:10.444 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 60.317ms
12-02 23:54:10.586 2379-2379/com.brasiltradefx.btfxalerts E/c3+U6b5T6IHUG94DJ22teQVKojk=:: PMSeT4Q8FLTjYUOwNpnShvIlw4E=
12-02 23:54:10.642 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 28.796ms
12-02 23:54:10.843 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 17.736ms
12-02 23:54:11.102 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 56.667ms
12-02 23:54:11.294 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 9.199ms
12-02 23:54:11.595 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 78.174ms
12-02 23:54:11.648 2379-2390/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 32.152ms
12-02 23:54:11.720 2379-2390/com.brasiltradefx.btfxalerts I/art: Background sticky concurrent mark sweep GC freed 16851(1095KB) AllocSpace objects, 8(160KB) LOS objects, 58% free, 1549KB/3MB, paused 72.392ms total 254.775ms
12-02 23:54:11.733 2379-2390/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 12.266ms
12-02 23:54:11.837 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 32.684ms
12-02 23:54:12.008 2379-2379/com.brasiltradefx.btfxalerts D/BTFX Alerts: Creating IAB helper.
12-02 23:54:12.013 2379-2379/com.brasiltradefx.btfxalerts D/BTFX Alerts: Starting setup.
12-02 23:54:12.013 2379-2379/com.brasiltradefx.btfxalerts D/IabHelper: Starting in-app billing setup.
12-02 23:54:12.017 2379-2379/com.brasiltradefx.btfxalerts D/BTFX Alerts: Setup finished.
12-02 23:54:12.017 2379-2379/com.brasiltradefx.btfxalerts E/BTFX Alerts: **** BTFX Alerts Error: Problem setting up in-app billing: IabResult: Billing service unavailable on device. (response: 3:Billing Unavailable)
12-02 23:54:12.017 2379-2379/com.brasiltradefx.btfxalerts D/BTFX Alerts: Showing alert dialog: Error: Problem setting up in-app billing: IabResult: Billing service unavailable on device. (response: 3:Billing Unavailable)
12-02 23:54:12.039 2379-2447/com.brasiltradefx.btfxalerts D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
12-02 23:54:12.306 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 83.896ms
12-02 23:54:12.513 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 16.090ms
12-02 23:54:12.678 2379-2456/com.brasiltradefx.btfxalerts W/GooglePlayServicesUtil: Google Play services out of date. Requires 8298000 but found 8185470
12-02 23:54:12.793 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 28.924ms
12-02 23:54:12.866 2379-2379/com.brasiltradefx.btfxalerts I/Choreographer: Skipped 39 frames! The application may be doing too much work on its main thread.
12-02 23:54:12.984 2379-2447/com.brasiltradefx.btfxalerts I/OpenGLRenderer: Initialized EGL, version 1.4
12-02 23:54:13.322 2379-2447/com.brasiltradefx.btfxalerts W/EGL_emulation: eglSurfaceAttrib not implemented
12-02 23:54:13.322 2379-2447/com.brasiltradefx.btfxalerts W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xad760120, error=EGL_SUCCESS
12-02 23:54:13.452 2379-2447/com.brasiltradefx.btfxalerts W/EGL_emulation: eglSurfaceAttrib not implemented
12-02 23:54:13.452 2379-2447/com.brasiltradefx.btfxalerts W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xb3f9ece0, error=EGL_SUCCESS
12-02 23:54:13.586 2379-2379/com.brasiltradefx.btfxalerts I/Choreographer: Skipped 42 frames! The application may be doing too much work on its main thread.
12-02 23:54:14.275 2379-2379/com.brasiltradefx.btfxalerts I/Choreographer: Skipped 40 frames! The application may be doing too much work on its main thread.
12-02 23:54:20.201 2379-2447/com.brasiltradefx.btfxalerts E/Surface: getSlotFromBufferLocked: unknown buffer: 0xab79e080
12-02 23:54:20.247 2379-2379/com.brasiltradefx.btfxalerts W/InputEventReceiver: Attempted to finish an input event but the input event receiver has already been disposed.
12-02 23:54:22.122 2379-2447/com.brasiltradefx.btfxalerts W/EGL_emulation: eglSurfaceAttrib not implemented
12-02 23:54:22.122 2379-2447/com.brasiltradefx.btfxalerts W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xa11fec60, error=EGL_SUCCESS
12-02 23:54:22.625 2379-2447/com.brasiltradefx.btfxalerts E/Surface: getSlotFromBufferLocked: unknown buffer: 0xab79e0f0
12-02 23:54:26.348 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 21.880ms
12-02 23:54:26.514 2379-2447/com.brasiltradefx.btfxalerts W/EGL_emulation: eglSurfaceAttrib not implemented
12-02 23:54:26.514 2379-2447/com.brasiltradefx.btfxalerts W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xa0afc040, error=EGL_SUCCESS
12-02 23:54:26.556 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 47.918ms
12-02 23:54:27.095 2379-2447/com.brasiltradefx.btfxalerts E/Surface: getSlotFromBufferLocked: unknown buffer: 0xab79e160
12-02 23:54:27.284 2379-2379/com.brasiltradefx.btfxalerts D/Volley: [1] 1.onResponse: AlertMainActivity
12-02 23:54:27.284 2379-2379/com.brasiltradefx.btfxalerts W/System.err: org.json.JSONException: No value for profilePic
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at org.json.JSONObject.get(JSONObject.java:389)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at org.json.JSONObject.getString(JSONObject.java:550)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.brasiltradefx.btfxalerts.AlertMainActivity.parseJsonFeed(AlertMainActivity.java:113)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.brasiltradefx.btfxalerts.AlertMainActivity.access$100(AlertMainActivity.java:31)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.brasiltradefx.btfxalerts.AlertMainActivity$1.onResponse(AlertMainActivity.java:77)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.brasiltradefx.btfxalerts.AlertMainActivity$1.onResponse(AlertMainActivity.java:71)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.android.volley.toolbox.JsonRequest.deliverResponse(JsonRequest.java:65)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
12-02 23:54:27.285 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at android.os.Handler.handleCallback(Handler.java:739)
12-02 23:54:27.286 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95)
12-02 23:54:27.286 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at android.os.Looper.loop(Looper.java:148)
12-02 23:54:27.286 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5417)
12-02 23:54:27.286 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at java.lang.reflect.Method.invoke(Native Method)
12-02 23:54:27.286 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
12-02 23:54:27.286 2379-2379/com.brasiltradefx.btfxalerts W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
12-02 23:55:09.625 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 5.831ms
12-03 00:01:53.397 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 27.544ms
12-03 00:13:46.829 2379-2386/com.brasiltradefx.btfxalerts W/art: Suspending all threads took: 22.750ms
MainActivity - 解析json
package com.brasiltradefx.btfxalerts;
import com.brasiltradefx.btfxalerts.adapter.FeedListAdapter;
import com.brasiltradefx.btfxalerts.app.AppController;
import com.brasiltradefx.btfxalerts.data.FeedItem;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ListView;
import com.android.volley.Cache;
import com.android.volley.Cache.Entry;
import com.android.volley.Request.Method;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonObjectRequest;
/**
* Created by Deryk on 12/2/2015.
*/
public class AlertMainActivity extends Activity {
private static final String TAG = AlertMainActivity.class.getSimpleName();
private ListView listView;
private FeedListAdapter listAdapter;
private List<FeedItem> feedItems;
private String URL_FEED = "http://www.contrariantradefx.info/android/btfxalerts/alert.json";
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_alert_main);
listView = (ListView) findViewById(R.id.list);
feedItems = new ArrayList<FeedItem>();
listAdapter = new FeedListAdapter(this, feedItems);
listView.setAdapter(listAdapter);
// These two lines not needed,
// just to get the look of facebook (changing background color & hiding the icon)
//getActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor("#3b5998")));
//getActionBar().setIcon(
//new ColorDrawable(getResources().getColor(android.R.color.transparent)));
// We first check for cached request
Cache cache = AppController.getInstance().getRequestQueue().getCache();
Entry entry = cache.get(URL_FEED);
if (entry != null) {
// fetch the data from cache
try {
String data = new String(entry.data, "UTF-8");
try {
parseJsonFeed(new JSONObject(data));
} catch (JSONException e) {
e.printStackTrace();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
} else {
// making fresh volley request and getting json
JsonObjectRequest jsonReq = new JsonObjectRequest(Method.GET,
URL_FEED, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
VolleyLog.d(TAG, "Response: " + response.toString());
if (response != null) {
parseJsonFeed(response);
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
}
});
// Adding request to volley request queue
AppController.getInstance().addToRequestQueue(jsonReq);
}
}
/**
* Parsing json reponse and passing the data to feed view list adapter
* */
private void parseJsonFeed(JSONObject response) {
try {
JSONArray feedArray = response.getJSONArray("alert");
for (int i = 0; i < feedArray.length(); i++) {
JSONObject feedObj = (JSONObject) feedArray.get(i);
FeedItem item = new FeedItem();
item.setId(feedObj.getInt("id"));
item.setName(feedObj.getString("name"));
// Image might be null sometimes
String image = feedObj.isNull("image") ? null : feedObj
.getString("image");
item.setImge(image);
item.setStatus(feedObj.getString("status"));
item.setProfilePic(feedObj.getString("profilePic"));
item.setOrder_type(feedObj.getString("order_type"));
item.setPair(feedObj.getString("pair"));
item.setRate(feedObj.getString("rate"));
item.setQuick_target(feedObj.getString("quick_target"));
item.setLong_target(feedObj.getString("long_target"));
item.setStop_loss(feedObj.getString("stop_loss"));
item.setBreak_Even(feedObj.getString("break_even"));
item.setTimeStamp(feedObj.getString("timeStamp"));
// url might be null sometimes
String feedUrl = feedObj.isNull("url") ? null : feedObj
.getString("url");
item.setUrl(feedUrl);
feedItems.add(item);
}
// notify data changes to list adapter
listAdapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
FeedItem类 - 这里我注意到第13行的FeedItem是浅灰色的。它有一个错误，说它没有被使用。
public class FeedItem {
private int id;
private String name, status, image, profilePic, timeStamp, url, order_type, pair, rate, quick_target, long_target, stop_loss, break_even;
public FeedItem() {
}
public FeedItem(int id, String name, String image, String status,
String profilePic, String timeStamp, String url, String order_type, String pair, String rate, String quick_target, String long_target,
String stop_loss, String break_even) {
super();
this.id = id;
this.name = name;
this.image = image;
this.status = status;
this.profilePic = profilePic;
this.timeStamp = timeStamp;
this.url = url;
this.order_type = order_type;
this.pair = pair;
this.rate = rate;
this.quick_target = quick_target;
this.long_target = long_target;
this.stop_loss = stop_loss;
this.break_even = break_even;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getImge() {
return image;
}
public void setImge(String image) {
this.image = image;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getProfilePic() {
return profilePic;
}
public void setProfilePic(String profilePic) {
this.profilePic = profilePic;
}
public String getTimeStamp() {
return timeStamp;
}
public void setTimeStamp(String timeStamp) {
this.timeStamp = timeStamp;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getOrder_type() {
return order_type;
}
public void setOrder_type(String order_type) {
this.order_type = order_type;
}
public String getPair() {
return pair;
}
public void setPair(String pair) {
this.pair = pair;
}
public String getRate() {
return rate;
}
public void setRate(String rate) {
this.rate = rate;
}
public String getQuick_target() {
return quick_target;
}
public void setQuick_target(String quick_target) {
this.quick_target = quick_target;
}
public String getLong_target() {
return long_target;
}
public void setLong_target(String long_target) {
this.long_target = long_target;
}
public String getStop_loss() {
return stop_loss;
}
public void setStop_loss(String stop_loss) {
this.stop_loss = stop_loss;
}
public String getBreak_Even() {
return break_even;
}
public void setBreak_Even(String break_even) { this.break_even = break_even; }
}
FeedListAdapter
public class FeedListAdapter extends BaseAdapter {
private Activity activity;
private LayoutInflater inflater;
private List<FeedItem> feedItems;
ImageLoader imageLoader = AppController.getInstance().getImageLoader();
public FeedListAdapter(Activity activity, List<FeedItem> feedItems) {
this.activity = activity;
this.feedItems = feedItems;
}
@Override
public int getCount() {
return feedItems.size();
}
@Override
public Object getItem(int location) {
return feedItems.get(location);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null)
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
convertView = inflater.inflate(R.layout.feed_item, null);
if (imageLoader == null)
imageLoader = AppController.getInstance().getImageLoader();
TextView name = (TextView) convertView.findViewById(R.id.name);
TextView timestamp = (TextView) convertView
.findViewById(R.id.timestamp);
TextView statusMsg = (TextView) convertView
.findViewById(R.id.txtStatusMsg);
TextView url = (TextView) convertView.findViewById(R.id.txtUrl);
TextView order_type = (TextView) convertView.findViewById(R.id.txtOrderType);
TextView pair = (TextView) convertView.findViewById(R.id.txtPair);
TextView rate = (TextView) convertView.findViewById(R.id.txtRate);
TextView quick_target = (TextView) convertView.findViewById(R.id.txtQuick_Target);
TextView long_target = (TextView) convertView.findViewById(R.id.txtLong_Target);
TextView stop_loss = (TextView) convertView.findViewById(R.id.txtStop_Loss);
TextView break_even = (TextView) convertView.findViewById(R.id.txtBreak_Even);
NetworkImageView profilePic = (NetworkImageView) convertView.findViewById(R.id.profilePic);
FeedImageView feedImageView = (FeedImageView) convertView
.findViewById(R.id.feedImage1);
FeedItem item = feedItems.get(position);
name.setText(item.getName());
order_type.setText(item.getOrder_type());
pair.setText(item.getPair());
rate.setText(item.getRate());
quick_target.setText(item.getQuick_target());
long_target.setText(item.getLong_target());
stop_loss.setText(item.getStop_loss());
break_even.setText(item.getBreak_Even());
// Converting timestamp into x ago format
CharSequence timeAgo = DateUtils.getRelativeTimeSpanString(
Long.parseLong(item.getTimeStamp()),
System.currentTimeMillis(), DateUtils.SECOND_IN_MILLIS);
timestamp.setText(timeAgo);
// Chcek for empty status message
if (!TextUtils.isEmpty(item.getStatus())) {
statusMsg.setText(item.getStatus());
statusMsg.setVisibility(View.VISIBLE);
} else {
// status is empty, remove from view
statusMsg.setVisibility(View.GONE);
}
// Checking for null feed url
if (item.getUrl() != null) {
url.setText(Html.fromHtml("<a href=\"" + item.getUrl() + "\">"
+ item.getUrl() + "</a> "));
// Making url clickable
url.setMovementMethod(LinkMovementMethod.getInstance());
url.setVisibility(View.VISIBLE);
} else {
// url is null, remove from the view
url.setVisibility(View.GONE);
}
// user profile pic
profilePic.setImageUrl(item.getProfilePic(), imageLoader);
// Feed image
if (item.getImge() != null) {
feedImageView.setImageUrl(item.getImge(), imageLoader);
feedImageView.setVisibility(View.VISIBLE);
feedImageView
.setResponseObserver(new FeedImageView.ResponseObserver() {
@Override
public void onError() {
}
@Override
public void onSuccess() {
}
});
} else {
feedImageView.setVisibility(View.GONE);
}
return convertView;
}
}