我有一个带有按钮的片段，当按下该按钮时，会从微调器和文本框中获取数据，然后启动电子邮件。如果将onClick代码放入片段或片段加载到的主要活动中，我有点困惑。
我尝试将我的onclick方法放入我的片段中并强制关闭，然后我将其移动到我的MainDrawer2活动中并且我关闭了这个力：
02-24 19:28:39.835 27674-27674/com.beerportfolio.beerportfoliopro E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:3673)
at android.view.View.performClick(View.java:4280)
at android.view.View$PerformClick.run(View.java:17984)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:5789)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:843)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at android.view.View$1.onClick(View.java:3668)
at android.view.View.performClick(View.java:4280)
at android.view.View$PerformClick.run(View.java:17984)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:5789)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:843)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.beerportfolio.beerportfoliopro.MainDrawer2.sendFeedback(MainDrawer2.java:216)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at android.view.View$1.onClick(View.java:3668)
at android.view.View.performClick(View.java:4280)
at android.view.View$PerformClick.run(View.java:17984)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:5789)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:843)
at dalvik.system.NativeStart.main(Native Method)
我的联系页面片段：
public class ContactPage extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//set layout here
View v = inflater.inflate(R.layout.activity_contact, container, false);
setHasOptionsMenu(true);
getActivity().setTitle("Contact Page");
//get user information
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
String userName = prefs.getString("userName", null);
String userID = prefs.getString("userID", null);
// Inflate the layout for this fragment
return v;
}
}
ContactPage xml：
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
android:layout_marginTop="4dp"
android:layout_marginBottom="4dp"
android:orientation="vertical"
android:background="@drawable/bg_card">
<!-- Card Contents go here -->
<TextView
android:id="@+id/contactTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:ems="10"
android:text="Contact"
android:textSize="20sp"
android:textStyle = "bold"
android:padding="5dip"
>
</TextView>
</LinearLayout >
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
android:layout_marginTop="4dp"
android:layout_marginBottom="4dp"
android:orientation="vertical"
android:background="@drawable/bg_card">
<!-- Card Contents go here -->
<TextView
android:id="@+id/subjectTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:ems="10"
android:padding="5dip"
android:text="Subject:"
android:textSize="15sp"
android:textStyle="bold" >
</TextView>
<Spinner
android:id="@+id/contactSpinner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:entries="@array/contact_array"
/>
</LinearLayout >
</FrameLayout>
</FrameLayout>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
android:layout_marginTop="4dp"
android:layout_marginBottom="4dp"
android:orientation="vertical"
android:background="@drawable/bg_card">
<!-- Card Contents go here -->
<TextView
android:id="@+id/commentsTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:ems="10"
android:padding="5dip"
android:text="Comments:"
android:textSize="15sp"
android:textStyle="bold" >
</TextView>
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="textMultiLine"
android:minLines="4"
android:maxLines="7"
android:ems="10"
android:id="@+id/editTextContact"
/>
</LinearLayout >
</FrameLayout>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
android:layout_marginTop="4dp"
android:layout_marginBottom="4dp"
android:orientation="vertical"
android:background="@drawable/bg_card">
<!-- Card Contents go here -->
<Button
android:id="@+id/buttonContact"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:padding="5dip"
android:text="Submit Feedback"
android:onClick="sendFeedback"
/>
</LinearLayout >
</FrameLayout>
</LinearLayout>
</ScrollView>
MainDrawer2：
public class MainDrawer2 extends FragmentActivity
{
private static final String EXTRA_NAV_ITEM = "extraNavItem";
private static final String STATE_CURRENT_NAV = "stateCurrentNav";
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private NavDrawerListAdapter mDrawerAdapter;
private ListView mDrawerList;
private CharSequence mTitle;
private CharSequence mDrawerTitle;
private MainNavItem mCurrentNavItem;
public static Intent createLaunchFragmentIntent(Context context, MainNavItem navItem)
{
return new Intent(context, MainDrawer2.class)
.putExtra(EXTRA_NAV_ITEM, navItem.ordinal());
}
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_main);
mTitle = mDrawerTitle = getTitle();
mDrawerLayout = (DrawerLayout)findViewById(R.id.drawer_layout);
mDrawerList = (ListView)findViewById(R.id.drawer);
getActionBar().setDisplayHomeAsUpEnabled(true);
enableHomeButtonIfRequired();
mDrawerAdapter = new NavDrawerListAdapter(getApplicationContext());
mDrawerList.setAdapter(mDrawerAdapter);
mDrawerList.setOnItemClickListener(new ListView.OnItemClickListener()
{
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
displayNavFragment((MainNavItem)parent.getItemAtPosition(position));
}
});
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.drawable.ic_drawer, R.string.app_name, R.string.app_name)
{
public void onDrawerClosed(View view)
{
getActionBar().setTitle(mTitle);
invalidateOptionsMenu();
}
public void onDrawerOpened(View drawerView)
{
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu();
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if(getIntent().hasExtra(EXTRA_NAV_ITEM)){
MainNavItem navItem = MainNavItem.values()
[getIntent().getIntExtra(EXTRA_NAV_ITEM,
MainNavItem.STATISTICS.ordinal())];
displayNavFragment(navItem);
}
else if(savedInstanceState != null){
mCurrentNavItem = MainNavItem.values()
[savedInstanceState.getInt(STATE_CURRENT_NAV)];
setCurrentNavItem(mCurrentNavItem);
}
else{
displayNavFragment(MainNavItem.STATISTICS);
}
}
@TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
private void enableHomeButtonIfRequired()
{
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH){
getActionBar().setHomeButtonEnabled(true);
}
}
@Override
public void setTitle(CharSequence title)
{
mTitle = title;
getActionBar().setTitle(mTitle);
}
@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 toggles
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
protected void onSaveInstanceState(Bundle outState)
{
super.onSaveInstanceState(outState);
outState.putInt(STATE_CURRENT_NAV, mCurrentNavItem.ordinal());
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
/*
@Override
public boolean onPrepareOptionsMenu(Menu menu)
{
// if nav drawer is opened, hide the action items
boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
return super.onPrepareOptionsMenu(menu);
}
*/
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
if(mDrawerToggle.onOptionsItemSelected(item)){
return true;
}
switch(item.getItemId()){
case R.id.menu_search2:
displayNavFragment(MainNavItem.SEARCH);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private void displayNavFragment(MainNavItem navItem)
{
if(navItem == mCurrentNavItem){
return;
}
Fragment fragment = Fragment.instantiate(this,
navItem.getFragClass().getName());
if(fragment != null){
getSupportFragmentManager().beginTransaction()
.replace(R.id.main, fragment)
.commit();
setCurrentNavItem(navItem);
}
}
private void setCurrentNavItem(MainNavItem navItem)
{
int position = navItem.ordinal();
// If navItem is in DrawerAdapter
if(position >= 0 && position < mDrawerAdapter.getCount()){
mDrawerList.setItemChecked(position, true);
}
else{
// navItem not in DrawerAdapter, de-select current item
if(mCurrentNavItem != null){
mDrawerList.setItemChecked(mCurrentNavItem.ordinal(), false);
}
}
mDrawerLayout.closeDrawer(mDrawerList);
setTitle(navItem.getTitleResId());
mCurrentNavItem = navItem;
}
public void sendFeedback(View view){
//get spinner content
Spinner subjectSpinner = (Spinner) view.findViewById(R.id.contactSpinner);
String subjectText = subjectSpinner.getSelectedItem().toString();
//get feedback context
EditText feedback = (EditText)view.findViewById(R.id.editTextContact);
String feedbackToSend = feedback.getText().toString();
//launch gmail
Intent i = new Intent(Intent.ACTION_SEND);
i.setType("message/rfc822");
i.putExtra(Intent.EXTRA_EMAIL , new String[]{"mike@beerportfolio.com"});
i.putExtra(Intent.EXTRA_SUBJECT, subjectText);
i.putExtra(Intent.EXTRA_TEXT , feedbackToSend);
try {
startActivity(Intent.createChooser(i, "Send mail..."));
} catch (android.content.ActivityNotFoundException ex) {
Toast.makeText(this, "There are no email clients installed.", Toast.LENGTH_SHORT).show();
}
}
}
更新
稍微更改了我的代码。这次我尝试在代码中设置一个onCLick监听器，而不是依赖于xml中的onClick。我片段的新代码是：
public class ContactPage extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//set layout here
View v = inflater.inflate(R.layout.activity_contact, container, false);
setHasOptionsMenu(true);
getActivity().setTitle("Contact Page");
//get user information
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
String userName = prefs.getString("userName", null);
String userID = prefs.getString("userID", null);
Button bt = (Button) v.findViewById(R.id.buttonContact);
bt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Spinner subjectSpinner = (Spinner) v.findViewById(R.id.contactSpinner);
String subjectText = subjectSpinner.getSelectedItem().toString();
//get feedback context
EditText feedback = (EditText)v.findViewById(R.id.editTextContact);
String feedbackToSend = feedback.getText().toString();
//launch gmail
Intent i = new Intent(Intent.ACTION_SEND);
i.setType("message/rfc822");
i.putExtra(Intent.EXTRA_EMAIL , new String[]{"mike@beerportfolio.com"});
i.putExtra(Intent.EXTRA_SUBJECT, subjectText);
i.putExtra(Intent.EXTRA_TEXT , feedbackToSend);
try {
startActivity(Intent.createChooser(i, "Send mail..."));
} catch (android.content.ActivityNotFoundException ex) {
Toast.makeText(getActivity(), "There are no email clients installed.", Toast.LENGTH_SHORT).show();
}
}
});
// Inflate the layout for this fragment
return v;
}
}
我仍然在线上发出强制关闭错误：
String subjectText = subjectSpinner.getSelectedItem().toString();
力量关闭：
02-24 20:13:32.078 32759-32759/com.beerportfolio.beerportfoliopro E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at com.beerportfolio.beerportfoliopro.ContactPage$1.onClick(ContactPage.java:47)
at android.view.View.performClick(View.java:4280)
at android.view.View$PerformClick.run(View.java:17984)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:5789)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:843)
at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：1)
//你已经引用查看为v
//这是你的根视图
View v = inflater.inflate(R.layout.activity_contact, container, false);
//并点击按钮，即可传递View v
public void onClick(View v) {
Spinner subjectSpinner = (Spinner) v.findViewById(R.id.contactSpinner);
<强>溶胶：
1) Declare the Spinner outside the onClick()
2) change the `onClick(View btnView)`
答案 1 :(得分：0)
// Why do u assume spinner always have something selected
spinner.setOnItemSelectedListener(this);
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id) {
// This is the point where u assume u have an item selected, not before this
// Here u will not get NPE
}
public void onNothingSelected(AdapterView<?> parent) {
// Another interface callback
}