我有一个带有 OnClickListener() 的文本框。此外，每当我在文本框中键入字母时，它都会使用一些声音文件大声朗读出来。问题是在读出/输入 5-6 个字母后，应用程序意外终止。我无法弄清楚原因。为什么会这样？
代码在这里：
package com.example.newaa;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.support.v4.app.NavUtils;
import android.text.Editable;
import android.text.TextWatcher;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.os.Bundle;
public class Recipient extends Activity{
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.recipient);
EditText a;
a=(EditText)findViewById(R.id.editText3);
a.addTextChangedListener(new TextWatcher(){
@Override
public void afterTextChanged(Editable s) {
//GET TEXT HERE AFTER TYPING DONE BY PERSON
}
@Override
public void beforeTextChanged(CharSequence s,int start,int count,int after){
//GET TEXT HERE BEFORE TYPING START BY PERSON
}
@SuppressLint("ParserError")
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
//GET TYPED CHAR HERE
char ch=s.charAt(s.length()-1);
if(ch=='a')
{
MediaPlayer mPlayer1 = MediaPlayer.create(Recipient.this, R.raw.a);
mPlayer1.start();
}
if(ch=='b')
{
MediaPlayer mPlayer2 = MediaPlayer.create(Recipient.this, R.raw.b);
mPlayer2.start();
}
if(ch=='c')
{
MediaPlayer mPlayer3 = MediaPlayer.create(Recipient.this, R.raw.c);
mPlayer3.start();
}
if(ch=='d')
{
MediaPlayer mPlayer4 = MediaPlayer.create(Recipient.this, R.raw.d);
mPlayer4.start();
}
if(ch=='e')
{
MediaPlayer mPlayer5 = MediaPlayer.create(Recipient.this, R.raw.e);
mPlayer5.start();
}
if(ch=='f')
{
MediaPlayer mPlayer6 = MediaPlayer.create(Recipient.this, R.raw.f);
mPlayer6.start();
}
if(ch=='g')
{
MediaPlayer mPlayer7 = MediaPlayer.create(Recipient.this, R.raw.g);
mPlayer7.start();
}
if(ch=='h')
{
MediaPlayer mPlayer8 = MediaPlayer.create(Recipient.this, R.raw.h);
mPlayer8.start();
}
if(ch=='i')
{
MediaPlayer mPlayer9 = MediaPlayer.create(Recipient.this, R.raw.i);
mPlayer9.start();
}
if(ch=='j')
{
MediaPlayer mPlayer10 = MediaPlayer.create(Recipient.this, R.raw.j);
mPlayer10.start();
}
if(ch=='k')
{
MediaPlayer mPlayer11 = MediaPlayer.create(Recipient.this, R.raw.k);
mPlayer11.start();
}
if(ch=='l')
{
MediaPlayer mPlayer12 = MediaPlayer.create(Recipient.this, R.raw.l);
mPlayer12.start();
}
if(ch=='m')
{
MediaPlayer mPlayer13 = MediaPlayer.create(Recipient.this, R.raw.m);
mPlayer13.start();
}
if(ch=='n')
{
MediaPlayer mPlayer14 = MediaPlayer.create(Recipient.this, R.raw.n);
mPlayer14.start();
}
if(ch=='o')
{
MediaPlayer mPlayer15 = MediaPlayer.create(Recipient.this, R.raw.o);
mPlayer15.start();
}
if(ch=='p')
{
MediaPlayer mPlayer16 = MediaPlayer.create(Recipient.this, R.raw.p);
mPlayer16.start();
}
if(ch=='q')
{
MediaPlayer mPlayer17 = MediaPlayer.create(Recipient.this, R.raw.q);
mPlayer17.start();
}
if(ch=='r')
{
MediaPlayer mPlayer18 = MediaPlayer.create(Recipient.this, R.raw.r);
mPlayer18.start();
}
if(ch=='s')
{
MediaPlayer mPlayer19 = MediaPlayer.create(Recipient.this, R.raw.s);
mPlayer19.start();
}
if(ch=='t')
{
MediaPlayer mPlayer20 = MediaPlayer.create(Recipient.this, R.raw.t);
mPlayer20.start();
}
if(ch=='u')
{
MediaPlayer mPlayer21 = MediaPlayer.create(Recipient.this, R.raw.u);
mPlayer21.start();
}
if(ch=='v')
{
MediaPlayer mPlayer22 = MediaPlayer.create(Recipient.this, R.raw.v);
mPlayer22.start();
}
if(ch=='w')
{
MediaPlayer mPlayer23 = MediaPlayer.create(Recipient.this, R.raw.w);
mPlayer23.start();
}
if(ch=='x')
{
MediaPlayer mPlayer24 = MediaPlayer.create(Recipient.this, R.raw.x);
mPlayer24.start();
}
if(ch=='y')
{
MediaPlayer mPlayer25 = MediaPlayer.create(Recipient.this, R.raw.y);
mPlayer25.start();
}
if(ch=='z')
{
MediaPlayer mPlayer26 = MediaPlayer.create(Recipient.this, R.raw.z);
mPlayer26.start();
}
}
});
}
}
日志在这里：
07-05 08:08:42.153: E/AndroidRuntime(321): Uncaught handler: thread main exiting due to uncaught exception
07-05 08:08:42.183: E/AndroidRuntime(321): java.lang.NullPointerException
07-05 08:08:42.183: E/AndroidRuntime(321): at com.example.newaa.Recipient$1.onTextChanged(Recipient.java:79)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.widget.TextView.sendOnTextChanged(TextView.java:6131)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.widget.TextView.handleTextChanged(TextView.java:6172)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:6316)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.text.SpannableStringBuilder.sendTextChange(SpannableStringBuilder.java:889)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:352)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:269)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:432)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:409)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:28)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.view.inputmethod.BaseInputConnection.replaceText(BaseInputConnection.java:578)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.view.inputmethod.BaseInputConnection.commitText(BaseInputConnection.java:174)
07-05 08:08:42.183: E/AndroidRuntime(321): at com.android.internal.widget.EditableInputConnection.commitText(EditableInputConnection.java:120)
07-05 08:08:42.183: E/AndroidRuntime(321): at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:231)
07-05 08:08:42.183: E/AndroidRuntime(321): at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:57)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.os.Handler.dispatchMessage(Handler.java:99)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.os.Looper.loop(Looper.java:123)
07-05 08:08:42.183: E/AndroidRuntime(321): at android.app.ActivityThread.main(ActivityThread.java:4363)
07-05 08:08:42.183: E/AndroidRuntime(321): at java.lang.reflect.Method.invokeNative(Native Method)
07-05 08:08:42.183: E/AndroidRuntime(321): at java.lang.reflect.Method.invoke(Method.java:521)
07-05 08:08:42.183: E/AndroidRuntime(321): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
07-05 08:08:42.183: E/AndroidRuntime(321): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
07-05 08:08:42.183: E/AndroidRuntime(321): at dalvik.system.NativeStart.main(Native Method)