我正在尝试使用tab-swipe在网格视图中显示图像。但是当包含async-task从json URL获取图像时，应用程序甚至无法启动。它只是崩溃和关闭。这是我的代码。
import android.support.v4.app.Fragment;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.GridView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
public class GamesFragment extends Fragment {
public GamesFragment(){}
// Declare Variables
JSONObject jsonobject;
JSONArray jsonarray;
GridView gridview;
GridViewAdapter adapter;
ProgressDialog mProgressDialog;
ArrayList<HashMap<String, String>> arraylist;
ArrayList<HashMap<String, String>> items;
private Button button;
static String CATEGORY = "category";
int setlimit = 6;
int tolimit = 5;
static String IMAGE = "image";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.gridview_main, container, false);
new DownloadJSON().execute();
return rootView;
}
// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Create a progressdialog
mProgressDialog = new ProgressDialog(getActivity());
// Set progressdialog title
mProgressDialog.setTitle("Student Government App");
// Set progressdialog message
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... params) {
// Create an array
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions
.getJSONfromURL
("http://jsonurl.com");
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("wallpaper");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
map.put("category", jsonobject.getString("category"));
map.put("image", jsonobject.getString("image"));
// Set the JSON Objects into the array
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void args) {
gridview = (GridView) getView().findViewById(R.id.gridViewCustom);
// Pass the results into ListViewAdapter.java
adapter = new GridViewAdapter(getActivity(), arraylist);
gridview.setAdapter(adapter);
mProgressDialog.dismiss();
}
}
}
如何防止应用程序崩溃？任何帮助都会很棒。
Logcat:
07-03 15:22:36.692 838-838/info.androidhive.tabsswipe D/ActivityThread﹕ ACT- AM_ON_PAUSE_CALLED ActivityRecord{41353570 token=android.os.BinderProxy@41352cb0 {info.androidhive.tabsswipe/info.androidhive.tabsswipe.MainActivity}}
07-03 15:22:36.707 838-838/info.androidhive.tabsswipe D/ActivityThread﹕ ACT-PAUSE_ACTIVITY_FINISHING handled : 0 / android.os.BinderProxy@41352cb0
07-03 15:22:36.904 838-838/info.androidhive.tabsswipe D/OpenGLRenderer﹕ Flushing caches (mode 0)
07-03 15:22:36.944 838-838/info.androidhive.tabsswipe D/OpenGLRenderer﹕ Flushing caches (mode 0)
07-03 15:22:36.989 838-838/info.androidhive.tabsswipe D/OpenGLRenderer﹕ Flushing caches (mode 0)
07-03 15:22:37.003 838-838/info.androidhive.tabsswipe E/WindowManager﹕ Activity info.androidhive.tabsswipe.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4136f300 that was originally added here
android.view.WindowLeaked: Activity info.androidhive.tabsswipe.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4136f300 that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:418)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:294)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:226)
at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:151)
at android.view.Window$LocalWindowManager.addView(Window.java:547)
at android.app.Dialog.show(Dialog.java:277)
at info.androidhive.tabsswipe.GamesFragment$DownloadJSON.onPreExecute(GamesFragment.java:65)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
at android.os.AsyncTask.execute(AsyncTask.java:534)
at info.androidhive.tabsswipe.GamesFragment.onCreateView(GamesFragment.java:48)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:938)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1115)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1478)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:478)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1068)
at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436)
at android.view.View.measure(View.java:15264)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4918)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15264)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:833)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:574)
at android.view.View.measure(View.java:15264)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4918)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2161)
at android.view.View.measure(View.java:15264)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2131)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1242)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1435)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1127)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4609)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:747)
at android.view.Choreographer.doCallbacks(Choreographer.java:567)
at android.view.Choreographer.doFrame(Choreographer.java:536)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:733)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:153)
at android.app.ActivityThread.main(ActivityThread.java:4987)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
at dalvik.system.NativeStart.main(Native Method)
07-03 15:22:37.004 838-838/info.androidhive.tabsswipe D/OpenGLRenderer﹕ Flushing caches (mode 0)
07-03 15:22:37.004 838-838/info.androidhive.tabsswipe D/ActivityThread﹕ ACT-DESTROY_ACTIVITY handled : 1 / android.os.BinderProxy@41352cb0
07-03 15:22:37.004 838-838/info.androidhive.tabsswipe D/OpenGLRenderer﹕ Flushing caches (mode 1)
答案 0 :(得分：2)
您应该在gridview
onCreateView(...)中初始化new DownloadJSON().execute();
gridview = (GridView) rootview.findViewById(R.id.gridViewCustom);
答案 1 :(得分：0)
像这样改变你的oncreateview
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.gridview_main, container, false);
gridview = (GridView) rootView.findViewById(R.id.gridViewCustom);
new DownloadJSON().execute();
return rootView;
}
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
ProgressDialog progressDialog = null;
@Override
protected void onPreExecute() {
progressDialog = new ProgressDialog(getActivity());
progressDialog.setMessage("Loading , Please wait...");
progressDialog.setIndeterminate(true);
progressDialog.setCancelable(false);
progressDialog.setCanceledOnTouchOutside(false);
progressDialog.show();
super.onPreExecute();
}
以这种方式更改你的onPostExecute
@Override
protected void onPostExecute(Void args) {
mProgressDialog.dismiss();
gridview = (GridView) getView().findViewById(R.id.gridViewCustom);
// Pass the results into ListViewAdapter.java
adapter = new GridViewAdapter(getActivity(), arraylist);
gridview.setAdapter(adapter);
super.onPostExecute(arg);
}
}
答案 2 :(得分：-1)
您在调试模式下打开该应用程序 并在控制台中查看错误（选择警告）并找到错误并清除它