请看一下我的源代码，我的应用程序在添加导航菜单后崩溃了。你能否告诉我在Google上搜索的所有内容有什么问题，但是无法解决这个问题？谢谢。
我的MainActivity看起来像：
package com.example.rssreader;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.SearchManager;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.support.v7.app.ActionBar;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private android.support.v4.app.ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mPlanetTitles;
RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
ReadRss readRss = new ReadRss(this, recyclerView);
readRss.execute();
mTitle = mDrawerTitle = getTitle();
mPlanetTitles = getResources().getStringArray(R.array.contents);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
// set a custom shadow that overlays the main content when the drawer opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
// set up the drawer's list view with items and click listener
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mPlanetTitles));
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new android.support.v4.app.ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
getWindow().setNavigationBarColor(getResources().getColor(R.color.colorPrimary));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.layout.main, menu);
return super.onCreateOptionsMenu(menu);
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content view
boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
// ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action buttons
switch(item.getItemId()) {
case R.id.action_websearch:
// create intent to perform web search for this planet
Intent intent = new Intent(Intent.ACTION_WEB_SEARCH);
// catch event that there's no activity to handle intent
if (intent.resolveActivity(getPackageManager()) != null) {
startActivity(intent);
} else {
Toast.makeText(this, R.string.app_not_available, Toast.LENGTH_LONG).show();
}
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/* The click listner for ListView in the navigation drawer */
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
}
private void selectItem(int position) {
// update the main content by replacing fragments
Fragment fragment = new PlanetFragment();
Bundle args = new Bundle();
args.putInt(PlanetFragment.ARG_CONTENT_NUMBER, position);
fragment.setArguments(args);
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();
// update selected item and title, then close the drawer
mDrawerList.setItemChecked(position, true);
setTitle(mPlanetTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
/**
* When using the ActionBarDrawerToggle, you must call it during
* onPostCreate() and onConfigurationChanged()...
*/
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Pass any configuration change to the drawer toggls
mDrawerToggle.onConfigurationChanged(newConfig);
}
/**
* Fragment that appears in the "content_frame", shows a planet
*/
public static class PlanetFragment extends Fragment {
public static final String ARG_CONTENT_NUMBER = "planet_number";
public PlanetFragment() {
// Empty constructor required for fragment subclasses
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_content, container, false);
int i = getArguments().getInt(ARG_CONTENT_NUMBER);
String planet = getResources().getStringArray(R.array.contents)[i];
int imageId = getResources().getIdentifier(planet.toLowerCase(Locale.getDefault()),
"drawable", getActivity().getPackageName());
((ImageView) rootView.findViewById(R.id.image)).setImageResource(imageId);
getActivity().setTitle(planet);
return rootView;
}
}
}
我的Activity_main.xml如下所示：
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ListView
android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#ccc"/>
</android.support.v4.widget.DrawerLayout>
Drawer_list_item.xml如下所示：
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/text1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceListItemSmall"
android:gravity="center_vertical"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:textColor="#113d5e"
android:background="?android:attr/activatedBackgroundIndicator"
android:minHeight="?android:attr/listPreferredItemHeightSmall"/>
Fragment_content.xml如下所示：
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000"
android:gravity="center"
android:padding="32dp" />
Main.xml看起来像：
<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000"
android:gravity="center"
android:padding="32dp" />
谢谢
答案 0 :(得分：0)
我能够通过为导航抽屉创建一个单独的类来解决该问题。但是，我正面临着RssFeeds的另一个问题。
公共类ReadRss扩展了AsyncTask和recyclerView.setLayoutManager（新的LinearLayoutManager（context）是应用程序在运行调试时崩溃时指向错误的位置。
这是ReadRss.java：
package tk.mattercast.myapplication;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
public class ReadRss extends AsyncTask<Void, Void, Void> {
Context context;
String address = "http://www.oecd.org/corruption/index.xml";
ProgressDialog progressDialog;
ArrayList<FeedItem>feedItems;
RecyclerView recyclerView;
URL url;
public ReadRss(Context context,RecyclerView recyclerView) {
this.recyclerView=recyclerView;
this.context = context;
progressDialog = new ProgressDialog(context);
progressDialog.setMessage("Fetching Data...");
}
@Override
protected void onPreExecute() {
progressDialog.show();
super.onPreExecute();
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
progressDialog.dismiss();
MyAdapter adapter=new MyAdapter(context,feedItems);
recyclerView.setLayoutManager(new LinearLayoutManager(context) {
@Override
public RecyclerView.LayoutParams generateDefaultLayoutParams() {
return null;
}
});
recyclerView.addItemDecoration(new VerticalSpace(50));
recyclerView.setAdapter(adapter);
}
@Override
protected Void doInBackground(Void... params) {
ProcessXml(Getdata());
return null;
}
private void ProcessXml(Document data) {
if (data != null) {
feedItems=new ArrayList<>();
Element root = data.getDocumentElement();
Node channel = root.getChildNodes().item(1);
NodeList items = channel.getChildNodes();
for (int i = 0; i < items.getLength(); i++) {
Node cureentchild = items.item(i);
if (cureentchild.getNodeName().equalsIgnoreCase("item")) {
FeedItem item=new FeedItem();
NodeList itemchilds = cureentchild.getChildNodes();
for (int j = 0; j < itemchilds.getLength(); j++) {
Node cureent = itemchilds.item(j);
if (cureent.getNodeName().equalsIgnoreCase("title")){
item.setTitle(cureent.getTextContent());
}else if (cureent.getNodeName().equalsIgnoreCase("description")){
item.setDescription(cureent.getTextContent());
}else if (cureent.getNodeName().equalsIgnoreCase("pubDate")){
item.setPubDate(cureent.getTextContent());
}else if (cureent.getNodeName().equalsIgnoreCase("link")){
item.setLink(cureent.getTextContent());
}
}
feedItems.add(item);
}
}
}
}
public Document Getdata() {
try {
url = new URL(address);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
InputStream inputStream = connection.getInputStream();
DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document xmlDoc = builder.parse(inputStream);
return xmlDoc;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
}