ImageButton使用GridView使應用程序崩潰

Question

大家好，我試圖在GridView上為Android應用添加一個ImageButton。 在我添加ImageButton之前，該應用程序運行良好。 這是logCat

這是我的XML

<RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<RelativeLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" >
<ImageButton
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/calendar"
 android:src="@drawable/android_calendar"
 android:layout_marginRight="120dp"
 android:layout_alignParentBottom="true"
 android:layout_alignParentLeft="true"
 android:layout_alignParentStart="true" />

</RelativeLayout>

<GridView xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/gridView"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:columnWidth="120dp"
 android:numColumns="auto_fit"
 android:stretchMode="columnWidth">
</GridView>

</RelativeLayout>

這是Java文件。

package com.yourname.photogallery;

import java.util.ArrayList;

import android.annotation.TargetApi;
import android.app.Activity;
import android.app.SearchManager;
import android.app.SearchableInfo;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.SearchView;

public class PhotoGalleryFragment extends VisibleFragment {
private static final String TAG = "PhotoGalleryFragment";
GridView mGridView;
ArrayList<GalleryItem> mItems;
ThumbnailDownloader<ImageView> mThumbnailThread;

private ImageButton calendarButt;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setRetainInstance(true);
    setHasOptionsMenu(true);

    updateItems();

    calendarButt = (ImageButton) mGridView.findViewById(R.id.calendar);
    calendarButt.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        }
    });

    //mThumbnailThread = new ThumbnailDownloader<ImageView>();
    mThumbnailThread = new ThumbnailDownloader<ImageView>(new Handler());
    mThumbnailThread.setListener(new  ThumbnailDownloader.Listener<ImageView>(){
        public void onThumbnailDownloaded(ImageView imageView, Bitmap  thumbnail) {
            if (isVisible()) {
                imageView.setImageBitmap(thumbnail);
            }
            }
        });

    mThumbnailThread.start();
    mThumbnailThread.getLooper();
    Log.i(TAG, "Background thread started");
}
public void updateItems() {
    new FetchItemsTask().execute();
}



@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.fragment_photo_gallery, container, false);


    mGridView = (GridView)v.findViewById(R.id.gridView);

    setupAdapter();

    mGridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> gridView, View view, int pos,
                                long id) {
            GalleryItem item = mItems.get(pos);

            Uri photoPageUri = Uri.parse(item.getPhotoPageUrl());
            Intent i = new Intent(getActivity(), PhotoPageActivity.class);
            i.setData(photoPageUri);

            startActivity(i);
        }
    });

    return v;
}

@Override
public void onDestroyView() {
    super.onDestroyView();
    mThumbnailThread.clearQueue();
}

@Override
@TargetApi(11)
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    super.onCreateOptionsMenu(menu, inflater);
    inflater.inflate(R.menu.fragment_photo_gallery, menu);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
        //pull out the SearchView
        MenuItem searchItem = menu.findItem(R.id.menu_item_search);
        SearchView searchView = (SearchView)searchItem.getActionView();

        //Get the data from out searchable.xml as a Searchable
        SearchManager searchManager = (SearchManager)getActivity()
                .getSystemService(Context.SEARCH_SERVICE);
        ComponentName name = getActivity().getComponentName();
        SearchableInfo searchInfo = searchManager.getSearchableInfo(name);
        searchView.setSearchableInfo(searchInfo);
    }
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.menu_item_search:
        getActivity().onSearchRequested();
        return true;
    case R.id.menu_item_clear:
        PreferenceManager.getDefaultSharedPreferences(getActivity())
        .edit()
        .putString(FlickrFetchr.PREF_SEARCH_QUERY, null)
        .commit();
        updateItems();
        return true;
        case R.id.menu_item_toggle_polling:
        boolean shouldStartAlarm = !PollService.isServiceAlarmOn(getActivity());
        PollService.setServiceAlarm(getActivity(), shouldStartAlarm);

            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
                getActivity().invalidateOptionsMenu();

            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}

@Override
public void onPrepareOptionsMenu(Menu menu) {
    super.onPrepareOptionsMenu(menu);

    MenuItem toggleItem = menu.findItem(R.id.menu_item_toggle_polling);
    if(PollService.isServiceAlarmOn(getActivity())) {
        toggleItem.setTitle(R.string.start_polling);
    }
}

@Override
public void onDestroy() {
    super.onDestroy();
    mThumbnailThread.quit();
    Log.i(TAG, "Background thread destroyed");
}



void setupAdapter() {
    if (getActivity() == null || mGridView == null) return;

    if (mItems !=null) {
        //mGridView.setAdapter(new ArrayAdapter<GalleryItem>(getActivity(), android.R.layout.simple_gallery_item, mItems));
    mGridView.setAdapter(new GalleryItemAdapter(mItems));
    }
    else {
        mGridView.setAdapter(null);
    }
}



private class FetchItemsTask extends AsyncTask<Void, Void, ArrayList<GalleryItem>>{
//private class FetchItemsTask extends AsyncTask<Void, Void, Void> {
    @Override
    protected ArrayList<GalleryItem> doInBackground(Void... params) {
    //protected Void doInBackground(Void... params) {
        /*try {
            String result = new FlickrFetchr().getUrl("http://www.google.com");
            Log.i(TAG, "Fetched contents of URL: " + result);
        }
        catch (IOException ioe) {
            Log.e(TAG, "Failed to fetch URL: ", ioe);
        }*/
        /*new FlickrFetchr().fetchItems();
        return null;*/
        //String query = "android"; //Just for testing
        Activity activity = getActivity();
        if(activity==null) 
            return new ArrayList<GalleryItem>();

        String query = PreferenceManager.getDefaultSharedPreferences(activity)
                .getString(FlickrFetchr.PREF_SEARCH_QUERY, null);
        if(query != null) {
            return new FlickrFetchr().search(query);
        }
        else {
        return new FlickrFetchr().fetchItems();
        }

        }
    @Override
    protected void onPostExecute(ArrayList<GalleryItem> items) {
        mItems = items;
        setupAdapter();
    }
    }
private class GalleryItemAdapter extends ArrayAdapter<GalleryItem> {
    public GalleryItemAdapter (ArrayList<GalleryItem> items) {
        super(getActivity(), 0, items);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = getActivity().getLayoutInflater()
                    .inflate(R.layout.gallery_item, parent, false);
        }
        ImageView imageView = (ImageView)convertView
                .findViewById(R.id.gallery_item_imageView);
                imageView.setImageResource(R.drawable.brian_up_close);
        GalleryItem item = getItem(position);
        mThumbnailThread.queueThumbnail(imageView,  item.getUrl());

                return convertView;
        }
    }
}

我猜想這與gridView.findViewById有關。 如果我摘下gridView並僅使用findViewById，則會收到無法解決的錯誤，並且正在尋找一個int arg。 提前致謝。

Answer 1

calendarButt = (ImageButton) mGridView.findViewById(R.id.calendar)

1. 此時mGridView可能尚未准備好

2. R.id.calendar不是您的gridview的子級。

3. 您應該將布局的v用作日歷圖像按鈕，將其移至onCreateView 。 calendarButt = (ImageButton) v.findViewById(R.id.calendar)