在CustomListview中使用TTS时出现NullPointerException

我有自定义列表视图，其中包含内容和TTS选项，而使用TTS其抛出空指针exception，Listview也没有显示我的应用程序已停止。错误显示在Logcat中。

Applicationadapter.java

public class ApplicationAdapter extends ArrayAdapter implements TextToSpeech.OnInitListener{ private List items; private LayoutInflater inflator; private MainActivity activity; private ProgressDialog dialog; public TextToSpeech tts; public ImageButton btnaudioprayer; public TextView text1; ArrayAdapter adapter; public ApplicationAdapter(MainActivity context, List items){ super(context, R.layout.activity_row, items); this.items = items; inflator = LayoutInflater.from(getContext()); activity=context; } @Override public int getCount(){ return items.size(); } @Override public View getView(int position, View convertView, ViewGroup parent){ ViewHolder holder = null; tts = new TextToSpeech(activity, ApplicationAdapter.this); //View v = convertView; if ( convertView == null ){ convertView = inflator.inflate(R.layout.activity_row, null); holder = new ViewHolder(); holder.text2 = (TextView) convertView.findViewById(R.id.text2); holder.text1 = (TextView) convertView.findViewById(R.id.text1); holder.count = (TextView) convertView.findViewById(R.id.count); holder.pray = (Button) convertView.findViewById(R.id.pray); holder.chk = (CheckBox) convertView.findViewById(R.id.checkbox); holder.btnSpeak = (ImageButton) convertView.findViewById(R.id.btnaudioprayer); convertView.setTag(holder); }else { holder = (ViewHolder) convertView.getTag(); } holder.chk.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton view, boolean isChecked) { int getPosition = (Integer) view.getTag(); items.get(getPosition).setSelected(view.isChecked()); } }); holder.pray.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { int getPosition= (Integer)v.getTag(); StringBuffer sb1 = new StringBuffer(); sb1.append("ID :"); sb1.append(Html.fromHtml(""+items.get(getPosition).getId())); sb1.append("\n"); activity.praydata(items.get(getPosition).getId()); } }); holder.btnSpeak.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View V) { speakOut(); } }); Application app = items.get(position); holder.chk.setTag(position); holder.pray.setTag(position); holder.text2.setText(Html.fromHtml(app.getTitle())); holder.text1.setText(Html.fromHtml(app.getContent())); holder.count.setText(app.getCount()+""); holder.chk.setChecked(app.isSelected()); return convertView; } static class ViewHolder { public TextView text2; public TextView text1; public TextView count; public CheckBox chk; public Button pray; public ImageButton btnSpeak; private TextToSpeech tts; } @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() { String text = text1.getText().toString(); tts.speak(text, TextToSpeech.QUEUE_FLUSH, null); } 

在这里我也提到了我的logcat错误。 在我的logcat错误中，它显示此行中的错误String text = text1.getText().toString(); 。 它抛出了NullPointerException ，它也显示了log.e文件。 它没有运行speakout()方法。

 07-18 12:17:11.456: E/TTS(2314): This Language is not supported 07-18 12:17:11.456: I/TextToSpeech(2314): Connected to ComponentInfo{com.svox.pico/com.svox.pico.PicoService} 07-18 12:17:11.586: D/AndroidRuntime(2314): Shutting down VM 07-18 12:17:11.586: W/dalvikvm(2314): threadid=1: thread exiting with uncaught exception (group=0x40a70930) 07-18 12:17:11.597: E/AndroidRuntime(2314): FATAL EXCEPTION: main 07-18 12:17:11.597: E/AndroidRuntime(2314): java.lang.NullPointerException 07-18 12:17:11.597: E/AndroidRuntime(2314): at com.example.jsonandroid.ApplicationAdapter.speakOut(ApplicationAdapter.java:182) 07-18 12:17:11.597: E/AndroidRuntime(2314): at com.example.jsonandroid.ApplicationAdapter.onInit(ApplicationAdapter.java:168) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.speech.tts.TextToSpeech.dispatchOnInit(TextToSpeech.java:640) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.speech.tts.TextToSpeech.access$1000(TextToSpeech.java:52) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.speech.tts.TextToSpeech$Connection.onServiceConnected(TextToSpeech.java:1297) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1101) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1118) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.os.Handler.handleCallback(Handler.java:725) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.os.Handler.dispatchMessage(Handler.java:92) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.os.Looper.loop(Looper.java:137) 07-18 12:17:11.597: E/AndroidRuntime(2314): at android.app.ActivityThread.main(ActivityThread.java:5039) 07-18 12:17:11.597: E/AndroidRuntime(2314): at java.lang.reflect.Method.invokeNative(Native Method) 07-18 12:17:11.597: E/AndroidRuntime(2314): at java.lang.reflect.Method.invoke(Method.java:511) 07-18 12:17:11.597: E/AndroidRuntime(2314): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 

在我的自定义列表视图中，我有文本和TTS按钮，同时单击按钮它必须播放内容的音频。

Answer 1

我会删除speakOut();的调用speakOut(); 在onInit(int status)我会修改speakOut(); function如下：

 private void speakOut(String text) { tts.speak(text, TextToSpeech.QUEUE_FLUSH, null); } 

你的onclicklistener我会在这里改为：

  @Override public void onClick(View v) { View parent = (View)v.getParent(); ViewHolder vh = (ViewHolder)parent.getTag(); TextView tv = vh.text1; speakOut(tv.getText().toString()); } 

这对你有用。

Answer 2

您的变量text1未初始化，但已声明，因此执行text1.getText() ，您实际上是尝试从null获取getText() 。

也许你想要的是holder.text1 （来自ViewHolder ）？