我创建了一个导航抽屉片段，在其中我打开位置以开始不同的活动。我尝试启动的活动（称为p2p_main）扩展了FragmentActivity。
以下是我尝试启动p2p_main活动的片段代码。第二个活动是导入项目的一部分（作为库模块导入），允许设备查找其他设备并通过WiFi直接连接。
当我选择案例1时，从我的导航抽屉片段中，我想启动p2p_main活动。当我点击按钮（应用程序崩溃）时出现以下错误：
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jonny.nav/com.mycompany.p2pwifi.p2p_main}: android.view.InflateException: Binary XML file line #19: Error inflating class fragment
package com.jonny.nav;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.Fragment;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
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.ListView;
import android.widget.Toast;
import com.example.fileexplorer.FileChooser;
import com.mycompany.p2pwifi.p2p_main;
/**
* Fragment used for managing interactions for and presentation of a navigation drawer.
* See the <a href="https://developer.android.com/design/patterns/navigation-drawer.html#Interaction">
* design guidelines</a> for a complete explanation of the behaviors implemented here.
*/
public class NavigationDrawerFragment extends Fragment {
/**
* Remember the position of the selected item.
*/
private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";
/**
* Per the design guidelines, you should show the drawer on launch until the user manually
* expands it. This shared preference tracks this.
*/
private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";
/**
* A pointer to the current callbacks instance (the Activity).
*/
private NavigationDrawerCallbacks mCallbacks;
/**
* Helper component that ties the action bar to the navigation drawer.
*/
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private ListView mDrawerListView;
private View mFragmentContainerView;
private int mCurrentSelectedPosition = 0;
private boolean mFromSavedInstanceState;
private boolean mUserLearnedDrawer;
public NavigationDrawerFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDrawerLayout = null;
// Read in the flag indicating whether or not the user has demonstrated awareness of the
// drawer. See PREF_USER_LEARNED_DRAWER for details.
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
// Select either the default item (0) or the last selected item.
//DEFAULT DEFAULT DEFAULT
//DEFAULT!!!!!
//selectItem(mCurrentSelectedPosition);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Indicate that this fragment would like to influence the set of actions in the action bar.
setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mDrawerListView = (ListView) inflater.inflate(
R.layout.fragment_navigation_drawer, container, false);
mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectItem(position);
}
});
mDrawerListView.setAdapter(new ArrayAdapter<String>(
getActionBar().getThemedContext(),
android.R.layout.simple_list_item_activated_1,
android.R.id.text1,
new String[]{
getString(R.string.title_section1),
getString(R.string.title_section2),
getString(R.string.title_section3),
getString(R.string.title_section4),
}));
mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
return mDrawerListView;
}
public boolean isDrawerOpen() {
return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView);
}
/**
* Users of this fragment must call this method to set up the navigation drawer interactions.
*
* @param fragmentId The android:id of this fragment in its activity's layout.
* @param drawerLayout The DrawerLayout containing this fragment's UI.
*/
public void setUp(int fragmentId, DrawerLayout drawerLayout) {
mFragmentContainerView = getActivity().findViewById(fragmentId);
mDrawerLayout = drawerLayout;
// 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
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the navigation drawer and the action bar app icon.
mDrawerToggle = new ActionBarDrawerToggle(
getActivity(), /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.navigation_drawer_open, /* "open drawer" description for accessibility */
R.string.navigation_drawer_close /* "close drawer" description for accessibility */
) {
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
if (!isAdded()) {
return;
}
getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if (!isAdded()) {
return;
}
if (!mUserLearnedDrawer) {
// The user manually opened the drawer; store this flag to prevent auto-showing
// the navigation drawer automatically in the future.
mUserLearnedDrawer = true;
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(getActivity());
sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply();
}
getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
}
};
// If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer,
// per the navigation drawer design guidelines.
if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
mDrawerLayout.openDrawer(mFragmentContainerView);
}
// Defer code dependent on restoration of previous instance state.
mDrawerLayout.post(new Runnable() {
@Override
public void run() {
mDrawerToggle.syncState();
}
});
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
/*
Determine which activity to start based on selected item.
*/
private void selectItem(int position) {
/* mCurrentSelectedPosition = position;
if (mDrawerListView != null) {
mDrawerListView.setItemChecked(position, true);
}
if (mDrawerLayout != null) {
mDrawerLayout.closeDrawer(mFragmentContainerView);
}
if (mCallbacks != null) {
mCallbacks.onNavigationDrawerItemSelected(position);
}*/
Intent selectedIntent = null;
switch(position){
case 0: //file explorer activity will need to move to Robert's code
{
//Start p2p_main's code here
selectedIntent = new Intent(getActivity(), FileChooser.class);
getActivity().startActivity(selectedIntent);
break;
}
case 1:
{
//start file explorer
selectedIntent = new Intent(getActivity(), p2p_main.class);
startActivity(selectedIntent);
break;
}
case 2:
{
break;
}
case 3:
{
break;
}
default:
break;
}
mDrawerListView.setItemChecked(position,true);
mDrawerLayout.closeDrawer(mDrawerListView);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallbacks = (NavigationDrawerCallbacks) activity;
} catch (ClassCastException e) {
throw new ClassCastException("Activity must implement NavigationDrawerCallbacks.");
}
}
@Override
public void onDetach() {
super.onDetach();
mCallbacks = null;
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Forward the new configuration the drawer toggle component.
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// If the drawer is open, show the global app actions in the action bar. See also
// showGlobalContextActionBar, which controls the top-left area of the action bar.
if (mDrawerLayout != null && isDrawerOpen()) {
inflater.inflate(R.menu.global, menu);
showGlobalContextActionBar();
}
super.onCreateOptionsMenu(menu, inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
if (item.getItemId() == R.id.action_example) {
Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT).show();
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Per the navigation drawer design guidelines, updates the action bar to show the global app
* 'context', rather than just what's in the current screen.
*/
private void showGlobalContextActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setTitle(R.string.app_name);
}
private ActionBar getActionBar() {
return ((ActionBarActivity) getActivity()).getSupportActionBar();
}
/**
* Callbacks interface that all activities using this fragment must implement.
*/
public interface NavigationDrawerCallbacks {
/**
* Called when an item in the navigation drawer is selected.
*/
void onNavigationDrawerItemSelected(int position);
}
}
以下是我要开始的活动的代码。
package com.mycompany.p2pwifi;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.wifi.WpsInfo;
import android.net.wifi.p2p.WifiP2pConfig;
import android.net.wifi.p2p.WifiP2pDevice;
import android.net.wifi.p2p.WifiP2pManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import com.example.fileexplorer.FileChooser;
import java.util.ArrayList;
import java.util.List;
public class p2p_main extends FragmentActivity {
ListView listView;
private final IntentFilter intentFilter = new IntentFilter();
WifiP2pManager.Channel mChannel;
WifiP2pManager mManager;
WiFiDirectBroadcastReceiver mReceiver;
boolean wifiP2pEnabled;
private List peers = new ArrayList();
private ArrayAdapter<String> adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.list);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
intentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
mChannel = mManager.initialize(this, getMainLooper(), null);
mReceiver = new WiFiDirectBroadcastReceiver(mManager, mChannel, this);
peers = mReceiver.get_peers();
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, peers);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
connect(position);
}
});
}
@Override
protected void onResume() {
super.onResume();
registerReceiver(mReceiver, intentFilter);
mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() {
@Override
public void onSuccess() {
Log.d("wifi", "onsuccess");
}
@Override
public void onFailure(int reason) {
Log.d("wifi", "onfailure");
}
});
}
@Override
protected void onPause() {
super.onPause();
unregisterReceiver(mReceiver);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void setIsWifiP2pEnabled(boolean s){
wifiP2pEnabled = s;
}
public boolean isWifiP2pEnabled(){
return wifiP2pEnabled;
}
/*public void discover_peers(View view) {
mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() {
@Override
public void onSuccess() {
Log.d("wifi", "onsuccess");
}
@Override
public void onFailure(int reason) {
Log.d("wifi", "onfailure");
}
});
}*/
public void update_list() {
this.adapter.notifyDataSetChanged();
}
public void connect(int position) {
WifiP2pDevice device = (WifiP2pDevice) peers.get(position);
WifiP2pConfig config = new WifiP2pConfig();
config.deviceAddress = device.deviceAddress;
config.wps.setup = WpsInfo.PBC;
mManager.connect(mChannel, config, new WifiP2pManager.ActionListener() {
@Override
public void onSuccess() {
/*Intent intent = new Intent(this.getActivity(), FileChooser.class);
String
startActivity(intent);*/
}
@Override
public void onFailure(int reason) {
Log.d("connect", "Failed to connect to device.");
}
});
}
public void start_explorer(){
Intent file_explorer = new Intent(getApplicationContext(), FileChooser.class);
startActivity(file_explorer);
}
}
这是主要活动（导航抽屉）的activity_main.xml
<!-- A DrawerLayout is intended to be used as the top-level content view using match_parent for both width and height to consume the full space available. -->
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:id="@+id/drawer_layout"
android:layout_width="match_parent" android:layout_height="match_parent"
tools:context=".MainActivity">
<!-- As the main content view, the view below consumes the entire
space available using match_parent in both dimensions. -->
<FrameLayout android:id="@+id/container" android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- android:layout_gravity="start" tells DrawerLayout to treat
this as a sliding drawer on the left side for left-to-right
languages and on the right side for right-to-left languages.
If you're not building against API 17 or higher, use
android:layout_gravity="left" instead. -->
<!-- The drawer is given a fixed width in dp and extends the full height of
the container. -->
<fragment android:id="@+id/navigation_drawer"
android:layout_width="@dimen/navigation_drawer_width" android:layout_height="match_parent"
android:layout_gravity="start" android:name="com.jonny.nav.NavigationDrawerFragment"
tools:layout="@layout/fragment_navigation_drawer" />
</android.support.v4.widget.DrawerLayout>
这是包含p2p_main
的项目的activity_main.xml<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:orientation="vertical"
tools:context=".p2p_main">
<!--<Button android:layout_height="wrap_content"
android:layout_width="wrap_co1ntent"
android:text="@string/discover_peers"
android:onClick="discover_peers"
android:layout_gravity="left" />-->
<ListView
android:id="@+id/list"
android:layout_height="wrap_content"
android:layout_width="match_parent">
</ListView>
</LinearLayout>