我在 Android 中收到 nullPointerException。我正在通过通知实现文字转语音功能
I am getting nullPointerException in Android. I am implementing texttospeech functionality with the notification
package com.example.trynot;
import java.io.IOException;
import java.util.Calendar;
import java.util.Locale;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.mail.Address;
import javax.mail.BodyPart;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.NoSuchProviderException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Flags.Flag;
import javax.mail.search.FlagTerm;
import com.example.trynot.MainActivity;
import com.example.trynot.R;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningServiceInfo;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.sax.StartElementListener;
import android.speech.tts.TextToSpeech;
import android.support.v4.app.NotificationCompat;
import android.support.v4.app.NotificationCompat.Builder;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import android.speech.tts.TextToSpeech;
public class MainActivity extends Activity {
public static Context c,b;
public static Intent serviceIntent;
private static int myNotificationId;
public static class ReadMailSample extends AsyncTask<String,String,Void> implements TextToSpeech.OnInitListener{
Message message;
private TextToSpeech tts;
static String command, phoneNumber, type, priority, name, time_stamp, imei, opt1, opt2, opt3, fromSubString;
Properties properties = null;
private Session session = null;
private Store store = null;
private Folder inbox = null;
String userName="avarote1994@gmail.com" ; // PROVIDE RECEPIENT EMAIL ID
String password="amul11111994" ; // PROVIDE RECEPIENT PASSWORD
static SQLiteDatabase db;
boolean flag=false;
Context acn;
//private Bundle savedInstanceState;
protected Void doInBackground(String...params){ // SEPARATE THREAD TO RUN IN THE BACKGROUND
try{
readMails();
}
catch(Exception e){
Logger logger = Logger.getAnonymousLogger();
logger.log(Level.INFO, "an exception was thrown", e);
}
return null;
}
ReadMailSample(SQLiteDatabase db){
this.db = db;
}
ReadMailSample(){
}
ReadMailSample(Context cn){
acn=cn;
}
@Override
protected void onProgressUpdate(String... values) {
try {
System.out.println("---------------------adasd-----------" + time_stamp);
speakOut();
showNotification();
}
catch(Exception e){
e.printStackTrace();
}
}
public void onDestroy() {
// Don't forget to shutdown tts!
if (tts != null) {
tts.stop();
tts.shutdown();
}
//super.onDestroy();
}
@Override
public void onInit(int status) {
if (status == TextToSpeech.SUCCESS) {
int result = tts.setLanguage(Locale.US);
if (result == TextToSpeech.LANG_MISSING_DATA
|| result == TextToSpeech.LANG_NOT_SUPPORTED) {
Log.e("TTS", "This Language is not supported");
} else {
speakOut();
}
} else {
Log.e("TTS", "Initilization Failed!");
}
}
private void speakOut() {
tts.speak(command, TextToSpeech.QUEUE_FLUSH, null);
}
public void showNotification() {
PendingIntent notificationIntent = preparePendingIntent();
Notification notification = createBasicNotification(notificationIntent);
displayNotification(notification);
}
@SuppressLint("InlinedApi")
private PendingIntent preparePendingIntent() {
Intent intent=new Intent(c,MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
PendingIntent pendingIntent = PendingIntent.getActivity(
c,
0,
intent,
PendingIntent.FLAG_UPDATE_CURRENT);
return pendingIntent;
}
private Notification createBasicNotification(PendingIntent notificationIntent) {
NotificationCompat.Builder builder = new Builder(c);
long[] vibrationPattern = {0, 200, 800, 200, 600, 200, 400, 200, 200, 200, 100, 200, 50, 200, 50, 200, 50, 200, 50, 200};
Notification notification = builder
.setSmallIcon(R.drawable.ic_launcher)
.setContentTitle("Medication Reminder")
.setContentText(command)
.setAutoCancel(true)
.setContentIntent(notificationIntent)
.setWhen(Calendar.getInstance().getTimeInMillis() + 1000*60+60)
.setVibrate(vibrationPattern)
.build();
return notification;
}
private void displayNotification(Notification notification) {
NotificationManager notificationManager = (NotificationManager)c.getSystemService(Context.NOTIFICATION_SERVICE);
myNotificationId=(int) System.currentTimeMillis();
notificationManager.notify(myNotificationId , notification);
speakOut();
}
public void readMails() throws IOException{
System.out.println("READMAIL hi");
properties = new Properties();
// SETTING UP AN IMAP SERVER TO ACCESS THE RECEPIENT'S EMAIL
properties.setProperty("mail.host", "imap.gmail.com");
properties.setProperty("mail.port", "995");
properties.setProperty("mail.transport.protocol", "imaps");
while(true){// CONTINUOUSLY MONITOR INCOMING MAIL'S
//String cq = "select * from Login4";
//Cursor c = db.rawQuery(cq, null);
// c.moveToFirst();
//final String userName = c.getString(0);
//final String password = c.getString(1);
//String cloud = "avarote1994@gmail.com";
// AUTHENTICATE AND GET AN INSTANCE OF THE SESSION FROM THE SERVER
session = Session.getInstance(properties,new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(userName, password);
}
});
try {
store = session.getStore("imaps");
store.connect();
inbox = store.getFolder("INBOX"); // ACCESS THE INBOX OF THE RECEPIENT'S EMAIL ID
inbox.open(Folder.READ_WRITE); // OPEN THE INBOX IN READ-WRITE MODE
Message messages[] = inbox.search(new FlagTerm(new Flags(Flag.SEEN), false)); //SEARCH INBOX FOR ANY UNREAD MAILS
System.out.println("Number of mails = " + messages.length);
for (int i = 0; i < messages.length; i++) { // PROCESS ALL THE UNREAD MAILS
message = messages[i];
Address[] from = message.getFrom();
String from1 = from[0].toString();
System.out.println(from1);
if(from1.contains("<")){
int start = from1.indexOf("<");
int end = from1.indexOf(">");
fromSubString = from1.substring(start+1,end); // RETRIEVE THE SENDER'S EMAIL ID
} else{
fromSubString = from1;
}
System.out.println(fromSubString);
//if(fromSubString.equals(cloud)){ // CHECK WHETHER THE MAIL IS FROM THE CLOUD
String[] subject = message.getSubject().split(","); // SPLIT THE SUBJECT
System.out.println("hi");
type = subject[0]; // STORE THE DETAILS IN RESPECTIVE VARIABLES
phoneNumber =subject[1];
name = subject[2];
System.out.println(type);
System.out.println(phoneNumber);
System.out.println(name);
//String body=message.getContentType().toString();
// System.out.print(body);
processMessageBody(message);
System.out.println("--------------------------------");
// }
}
inbox.close(true);
store.close();
}
catch (NoSuchProviderException e) {
e.printStackTrace();
}
catch (MessagingException e) {
e.printStackTrace();
}
}
}
public void processMessageBody(Message message) {
try {
Object content = message.getContent();
String msg=content.toString();
System.out.println(msg);
if (content instanceof Multipart) { // IF MAIL HAS MULTIPART MESSAGE
Multipart multiPart = (Multipart) content;
procesMultiPart(multiPart);
}
else{
System.out.println("Content = "+content);
processSinglepart(content.toString());
}
}
catch (IOException e) {
e.printStackTrace();
}
catch (MessagingException e) {
e.printStackTrace();
}
}
public void processSinglepart(String content){
String[] body = content.split(","); // SPLIT THE CONTENTS OF THE BODY
System.out.println('1');
time_stamp = body[0]; // STORE THE DETAILS IN RESPECTIVE VARIABLES
command = body[3];
System.out.println(time_stamp);
//tts.speak(time_stamp, TextToSpeech.QUEUE_FLUSH, null);
publishProgress(command);
}
public void procesMultiPart(Multipart content) {
System.out.println("amulya");
try {
BodyPart bodyPart = content.getBodyPart(0); // RETRIEVE THE CONTENTS FROM THE BODY
Object o;
o = bodyPart.getContent();
if (o instanceof String) {
System.out.println("Content Multipart= "+o.toString());
processSinglepart(o.toString());
}
}
catch (IOException e) {
e.printStackTrace();
}
catch (MessagingException e) {
e.printStackTrace();
}
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
c = this.getApplicationContext();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (!isMyServiceRunning()){
serviceIntent = new Intent(getApplicationContext(),MyService.class);
c.startService(serviceIntent);
}
final SQLiteDatabase db = openOrCreateDatabase("GDV_DB_NEW_0711", Context.MODE_PRIVATE, null);
db.execSQL("CREATE TABLE IF NOT EXISTS Login4(mailid VARCHAR,password VARCHAR);");
db.execSQL("CREATE TABLE IF NOT EXISTS CLIENT_DATA(type VARCHAR,time_stamp VARCHAR,priority VARCHAR,result VARCHAR,opt1 VARCHAR,opt2 VARCHAR,opt3 VARCHAR);");
ReadMailSample rd=new ReadMailSample(getApplicationContext());
System.out.println("hello");
rd.execute();
System.out.println("------xvsdfsdfsd---------aefaefa-----------------");
}
private boolean isMyServiceRunning() {
ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
if (MyService.class.getName().equals(service.service.getClassName())) {
return true;
}
}
return false;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
有一个后台线程doInBackground()线程运行读取邮件，然后读取的邮件正文应与语音一起通知。现通知实施。但是当我包含 TextToSpeech 代码时，出现错误。
日志如下所示：
02-05 11:13:40.273: W/System.err(959): java.lang.NullPointerException
02-05 11:13:40.273: W/System.err(959): at com.example.trynot.MainActivity$ReadMailSample.speakOut(MainActivity.java:143)
02-05 11:13:40.273: W/System.err(959): at com.example.trynot.MainActivity$ReadMailSample.onProgressUpdate(MainActivity.java:99)
02-05 11:13:40.283: W/System.err(959): at com.example.trynot.MainActivity$ReadMailSample.onProgressUpdate(MainActivity.java:1)
02-05 11:13:40.283: W/System.err(959): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:648)
02-05 11:13:40.283: W/System.err(959): at android.os.Handler.dispatchMessage(Handler.java:102)
02-05 11:13:40.283: W/System.err(959): at android.os.Looper.loop(Looper.java:136)
02-05 11:13:40.283: W/System.err(959): at android.app.ActivityThread.main(ActivityThread.java:5001)
02-05 11:13:40.283: W/System.err(959): at java.lang.reflect.Method.invokeNative(Native Method)
02-05 11:13:40.293: W/System.err(959): at java.lang.reflect.Method.invoke(Method.java:515)
02-05 11:13:40.293: W/System.err(959): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
02-05 11:13:40.323: W/System.err(959): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
02-05 11:13:40.323: W/System.err(959): at dalvik.system.NativeStart.main(Native Method)
02-05 11:13:43.083: I/ActivityManager(364): Delay finish: com.android.providers.calendar/.CalendarProviderBroadcastReceiver
02-05 11:13:43.163: I/ActivityManager(364): Resuming delayed broadcast
02-05 11:13:44.873: I/System.out(959): Number of mails = 0
02-05 11:13:45.853: D/dalvikvm(510): GC_FOR_ALLOC freed 529K, 17% free 3306K/3944K, paused 150ms, total 157ms
02-05 11:13:49.073: I/System.out(959): Number of mails = 0
02-05 11:13:51.203: I/MediaFocusControl(364): AudioFocus abandonAudioFocus() from android.media.AudioManager@b2d85530com.android.music.MediaPlaybackService@b2d843b0
02-05 11:13:53.273: I/System.out(959): Number of mails = 0
02-05 11:13:54.583: D/dalvikvm(959): GC_FOR_ALLOC freed 450K, 16% free 3158K/3728K, paused 88ms, total 88ms
02-05 11:13:57.883: I/System.out(959): Number of mails = 0
你的TextToSpeech(tts)是null，你忘了实例化它。
覆盖 AsyncTask 的 onPreExecute() 方法，然后添加 tts = new TextToSpeech(Context, ReadMailSample.this); 以实例化 TextToSpeech:
@Override
protected void onPreExecute() {
super.onPreExecute();
tts = new TextToSpeech(Context, ReadMailSample.this); // i think your Context is "acn", make sure its not null when onPreExecute() is called
}
PS:
没有理由导入TextToSpeech两次！ (import android.speech.tts.TextToSpeech;)
package com.example.trynot;
import java.io.IOException;
import java.util.Calendar;
import java.util.Locale;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.mail.Address;
import javax.mail.BodyPart;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.NoSuchProviderException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Flags.Flag;
import javax.mail.search.FlagTerm;
import com.example.trynot.MainActivity;
import com.example.trynot.R;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.ActivityManager;
import android.app.ActivityManager.RunningServiceInfo;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.sax.StartElementListener;
import android.speech.tts.TextToSpeech;
import android.support.v4.app.NotificationCompat;
import android.support.v4.app.NotificationCompat.Builder;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import android.speech.tts.TextToSpeech;
public class MainActivity extends Activity {
public static Context c,b;
public static Intent serviceIntent;
private static int myNotificationId;
public static class ReadMailSample extends AsyncTask<String,String,Void> implements TextToSpeech.OnInitListener{
Message message;
private TextToSpeech tts;
static String command, phoneNumber, type, priority, name, time_stamp, imei, opt1, opt2, opt3, fromSubString;
Properties properties = null;
private Session session = null;
private Store store = null;
private Folder inbox = null;
String userName="avarote1994@gmail.com" ; // PROVIDE RECEPIENT EMAIL ID
String password="amul11111994" ; // PROVIDE RECEPIENT PASSWORD
static SQLiteDatabase db;
boolean flag=false;
Context acn;
//private Bundle savedInstanceState;
protected Void doInBackground(String...params){ // SEPARATE THREAD TO RUN IN THE BACKGROUND
try{
readMails();
}
catch(Exception e){
Logger logger = Logger.getAnonymousLogger();
logger.log(Level.INFO, "an exception was thrown", e);
}
return null;
}
ReadMailSample(SQLiteDatabase db){
this.db = db;
}
ReadMailSample(){
}
ReadMailSample(Context cn){
acn=cn;
}
@Override
protected void onProgressUpdate(String... values) {
try {
System.out.println("---------------------adasd-----------" + time_stamp);
speakOut();
showNotification();
}
catch(Exception e){
e.printStackTrace();
}
}
public void onDestroy() {
// Don't forget to shutdown tts!
if (tts != null) {
tts.stop();
tts.shutdown();
}
//super.onDestroy();
}
@Override
public void onInit(int status) {
if (status == TextToSpeech.SUCCESS) {
int result = tts.setLanguage(Locale.US);
if (result == TextToSpeech.LANG_MISSING_DATA
|| result == TextToSpeech.LANG_NOT_SUPPORTED) {
Log.e("TTS", "This Language is not supported");
} else {
speakOut();
}
} else {
Log.e("TTS", "Initilization Failed!");
}
}
private void speakOut() {
tts.speak(command, TextToSpeech.QUEUE_FLUSH, null);
}
public void showNotification() {
PendingIntent notificationIntent = preparePendingIntent();
Notification notification = createBasicNotification(notificationIntent);
displayNotification(notification);
}
@SuppressLint("InlinedApi")
private PendingIntent preparePendingIntent() {
Intent intent=new Intent(c,MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
PendingIntent pendingIntent = PendingIntent.getActivity(
c,
0,
intent,
PendingIntent.FLAG_UPDATE_CURRENT);
return pendingIntent;
}
private Notification createBasicNotification(PendingIntent notificationIntent) {
NotificationCompat.Builder builder = new Builder(c);
long[] vibrationPattern = {0, 200, 800, 200, 600, 200, 400, 200, 200, 200, 100, 200, 50, 200, 50, 200, 50, 200, 50, 200};
Notification notification = builder
.setSmallIcon(R.drawable.ic_launcher)
.setContentTitle("Medication Reminder")
.setContentText(command)
.setAutoCancel(true)
.setContentIntent(notificationIntent)
.setWhen(Calendar.getInstance().getTimeInMillis() + 1000*60+60)
.setVibrate(vibrationPattern)
.build();
return notification;
}
private void displayNotification(Notification notification) {
NotificationManager notificationManager = (NotificationManager)c.getSystemService(Context.NOTIFICATION_SERVICE);
myNotificationId=(int) System.currentTimeMillis();
notificationManager.notify(myNotificationId , notification);
speakOut();
}
public void readMails() throws IOException{
System.out.println("READMAIL hi");
properties = new Properties();
// SETTING UP AN IMAP SERVER TO ACCESS THE RECEPIENT'S EMAIL
properties.setProperty("mail.host", "imap.gmail.com");
properties.setProperty("mail.port", "995");
properties.setProperty("mail.transport.protocol", "imaps");
while(true){// CONTINUOUSLY MONITOR INCOMING MAIL'S
//String cq = "select * from Login4";
//Cursor c = db.rawQuery(cq, null);
// c.moveToFirst();
//final String userName = c.getString(0);
//final String password = c.getString(1);
//String cloud = "avarote1994@gmail.com";
// AUTHENTICATE AND GET AN INSTANCE OF THE SESSION FROM THE SERVER
session = Session.getInstance(properties,new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(userName, password);
}
});
try {
store = session.getStore("imaps");
store.connect();
inbox = store.getFolder("INBOX"); // ACCESS THE INBOX OF THE RECEPIENT'S EMAIL ID
inbox.open(Folder.READ_WRITE); // OPEN THE INBOX IN READ-WRITE MODE
Message messages[] = inbox.search(new FlagTerm(new Flags(Flag.SEEN), false)); //SEARCH INBOX FOR ANY UNREAD MAILS
System.out.println("Number of mails = " + messages.length);
for (int i = 0; i < messages.length; i++) { // PROCESS ALL THE UNREAD MAILS
message = messages[i];
Address[] from = message.getFrom();
String from1 = from[0].toString();
System.out.println(from1);
if(from1.contains("<")){
int start = from1.indexOf("<");
int end = from1.indexOf(">");
fromSubString = from1.substring(start+1,end); // RETRIEVE THE SENDER'S EMAIL ID
} else{
fromSubString = from1;
}
System.out.println(fromSubString);
//if(fromSubString.equals(cloud)){ // CHECK WHETHER THE MAIL IS FROM THE CLOUD
String[] subject = message.getSubject().split(","); // SPLIT THE SUBJECT
System.out.println("hi");
type = subject[0]; // STORE THE DETAILS IN RESPECTIVE VARIABLES
phoneNumber =subject[1];
name = subject[2];
System.out.println(type);
System.out.println(phoneNumber);
System.out.println(name);
//String body=message.getContentType().toString();
// System.out.print(body);
processMessageBody(message);
System.out.println("--------------------------------");
// }
}
inbox.close(true);
store.close();
}
catch (NoSuchProviderException e) {
e.printStackTrace();
}
catch (MessagingException e) {
e.printStackTrace();
}
}
}
public void processMessageBody(Message message) {
try {
Object content = message.getContent();
String msg=content.toString();
System.out.println(msg);
if (content instanceof Multipart) { // IF MAIL HAS MULTIPART MESSAGE
Multipart multiPart = (Multipart) content;
procesMultiPart(multiPart);
}
else{
System.out.println("Content = "+content);
processSinglepart(content.toString());
}
}
catch (IOException e) {
e.printStackTrace();
}
catch (MessagingException e) {
e.printStackTrace();
}
}
public void processSinglepart(String content){
String[] body = content.split(","); // SPLIT THE CONTENTS OF THE BODY
System.out.println('1');
time_stamp = body[0]; // STORE THE DETAILS IN RESPECTIVE VARIABLES
command = body[3];
System.out.println(time_stamp);
//tts.speak(time_stamp, TextToSpeech.QUEUE_FLUSH, null);
publishProgress(command);
}
public void procesMultiPart(Multipart content) {
System.out.println("amulya");
try {
BodyPart bodyPart = content.getBodyPart(0); // RETRIEVE THE CONTENTS FROM THE BODY
Object o;
o = bodyPart.getContent();
if (o instanceof String) {
System.out.println("Content Multipart= "+o.toString());
processSinglepart(o.toString());
}
}
catch (IOException e) {
e.printStackTrace();
}
catch (MessagingException e) {
e.printStackTrace();
}
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
c = this.getApplicationContext();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (!isMyServiceRunning()){
serviceIntent = new Intent(getApplicationContext(),MyService.class);
c.startService(serviceIntent);
}
final SQLiteDatabase db = openOrCreateDatabase("GDV_DB_NEW_0711", Context.MODE_PRIVATE, null);
db.execSQL("CREATE TABLE IF NOT EXISTS Login4(mailid VARCHAR,password VARCHAR);");
db.execSQL("CREATE TABLE IF NOT EXISTS CLIENT_DATA(type VARCHAR,time_stamp VARCHAR,priority VARCHAR,result VARCHAR,opt1 VARCHAR,opt2 VARCHAR,opt3 VARCHAR);");
ReadMailSample rd=new ReadMailSample(getApplicationContext());
System.out.println("hello");
rd.execute();
System.out.println("------xvsdfsdfsd---------aefaefa-----------------");
}
private boolean isMyServiceRunning() {
ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
if (MyService.class.getName().equals(service.service.getClassName())) {
return true;
}
}
return false;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
有一个后台线程doInBackground()线程运行读取邮件，然后读取的邮件正文应与语音一起通知。现通知实施。但是当我包含 TextToSpeech 代码时，出现错误。
日志如下所示：
02-05 11:13:40.273: W/System.err(959): java.lang.NullPointerException
02-05 11:13:40.273: W/System.err(959): at com.example.trynot.MainActivity$ReadMailSample.speakOut(MainActivity.java:143)
02-05 11:13:40.273: W/System.err(959): at com.example.trynot.MainActivity$ReadMailSample.onProgressUpdate(MainActivity.java:99)
02-05 11:13:40.283: W/System.err(959): at com.example.trynot.MainActivity$ReadMailSample.onProgressUpdate(MainActivity.java:1)
02-05 11:13:40.283: W/System.err(959): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:648)
02-05 11:13:40.283: W/System.err(959): at android.os.Handler.dispatchMessage(Handler.java:102)
02-05 11:13:40.283: W/System.err(959): at android.os.Looper.loop(Looper.java:136)
02-05 11:13:40.283: W/System.err(959): at android.app.ActivityThread.main(ActivityThread.java:5001)
02-05 11:13:40.283: W/System.err(959): at java.lang.reflect.Method.invokeNative(Native Method)
02-05 11:13:40.293: W/System.err(959): at java.lang.reflect.Method.invoke(Method.java:515)
02-05 11:13:40.293: W/System.err(959): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
02-05 11:13:40.323: W/System.err(959): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
02-05 11:13:40.323: W/System.err(959): at dalvik.system.NativeStart.main(Native Method)
02-05 11:13:43.083: I/ActivityManager(364): Delay finish: com.android.providers.calendar/.CalendarProviderBroadcastReceiver
02-05 11:13:43.163: I/ActivityManager(364): Resuming delayed broadcast
02-05 11:13:44.873: I/System.out(959): Number of mails = 0
02-05 11:13:45.853: D/dalvikvm(510): GC_FOR_ALLOC freed 529K, 17% free 3306K/3944K, paused 150ms, total 157ms
02-05 11:13:49.073: I/System.out(959): Number of mails = 0
02-05 11:13:51.203: I/MediaFocusControl(364): AudioFocus abandonAudioFocus() from android.media.AudioManager@b2d85530com.android.music.MediaPlaybackService@b2d843b0
02-05 11:13:53.273: I/System.out(959): Number of mails = 0
02-05 11:13:54.583: D/dalvikvm(959): GC_FOR_ALLOC freed 450K, 16% free 3158K/3728K, paused 88ms, total 88ms
02-05 11:13:57.883: I/System.out(959): Number of mails = 0
你的TextToSpeech(tts)是null，你忘了实例化它。
覆盖 AsyncTask 的 onPreExecute() 方法，然后添加 tts = new TextToSpeech(Context, ReadMailSample.this); 以实例化 TextToSpeech:
@Override
protected void onPreExecute() {
super.onPreExecute();
tts = new TextToSpeech(Context, ReadMailSample.this); // i think your Context is "acn", make sure its not null when onPreExecute() is called
}
PS:
没有理由导入TextToSpeech两次！ (import android.speech.tts.TextToSpeech;)