Question

我正在创建一个涉及短信的Android应用程序，其中一个功能是输入时会读出每个字母。我正在使用 TextToSpeech 。

我让它在测试项目中工作但是当它集成到我自己的时候我会收到未知异常。

任何人都可以看到可能导致这种情况的原因并提出补救措施吗？我创建了一个名为speech的类，它在另一个类中实例化，并且有一个调用说出来的方法（类似于下面的第二个例子。）也可以解释为什么我需要在第一个例子上扩展Activity？同样有问题的一行表示“新TextToSpeech未定义”。

片段在哪里无效。错误在tts = new TextToSpeech(this, this);

public class Speech extends Activity implements TextToSpeech.OnInitListener {

    private TextToSpeech tts;
    private String toRead;

    public Speech(String toRead){

        this.toRead = toRead;
        tts = new TextToSpeech(this, this);
    }

以下是其工作原理的代码

public class MainActivity extends Activity implements
        TextToSpeech.OnInitListener {
    /** Called when the activity is first created. */

    private TextToSpeech tts;
    private Button btnSpeak;
    private EditText txtText;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tts = new TextToSpeech(this, this);

        btnSpeak = (Button) findViewById(R.id.btnSendSMS);

        txtText = (EditText) findViewById(R.id.txtMessage);

        // button on click event
        btnSpeak.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {
                speakOut();
            }

        });
    }

    @Override
    public void onDestroy() {
        // Don't forget to shutdown tts!
        if (tts != null) {
            tts.stop();
            tts.shutdown();
        }
        super.onDestroy();
    }

    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 {
                btnSpeak.setEnabled(true);
                speakOut();
            }

        } else {
            Log.e("TTS", "Initilization Failed!");
        }

    }

    private void speakOut() {

        String text = txtText.getText().toString();

        tts.speak(text, TextToSpeech.QUEUE_FLUSH, null);
    }
}

Logcat信息

02-13 20:00:54.974: D/AndroidRuntime(11127): Shutting down VM
02-13 20:00:54.974: W/dalvikvm(11127): threadid=1: thread exiting with uncaught exception (group=0x411cd300)
02-13 20:00:54.979: E/AndroidRuntime(11127): FATAL EXCEPTION: main
02-13 20:00:54.979: E/AndroidRuntime(11127): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{org.BT/org.BT.Text_entry}: java.lang.NullPointerException
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2024)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.app.ActivityThread.access$600(ActivityThread.java:140)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.os.Handler.dispatchMessage(Handler.java:99)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.os.Looper.loop(Looper.java:137)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.app.ActivityThread.main(ActivityThread.java:4898)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at java.lang.reflect.Method.invokeNative(Native Method)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at java.lang.reflect.Method.invoke(Method.java:511)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at dalvik.system.NativeStart.main(Native Method)
02-13 20:00:54.979: E/AndroidRuntime(11127): Caused by: java.lang.NullPointerException
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.content.ContextWrapper.getContentResolver(ContextWrapper.java:91)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.speech.tts.TtsEngines.getDefaultEngine(TtsEngines.java:75)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.speech.tts.TextToSpeech.getDefaultEngine(TextToSpeech.java:1235)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.speech.tts.TextToSpeech.initTts(TextToSpeech.java:595)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.speech.tts.TextToSpeech.<init>(TextToSpeech.java:553)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.speech.tts.TextToSpeech.<init>(TextToSpeech.java:527)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.speech.tts.TextToSpeech.<init>(TextToSpeech.java:512)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at org.BT.Speech.<init>(Speech.java:17)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at org.BT.Text_entry.<init>(Text_entry.java:48)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at java.lang.Class.newInstanceImpl(Native Method)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at java.lang.Class.newInstance(Class.java:1319)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.app.Instrumentation.newActivity(Instrumentation.java:1057)
02-13 20:00:54.979: E/AndroidRuntime(11127):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2015)
02-13 20:00:54.979: E/AndroidRuntime(11127):    ... 11 more

-----------------------------------------编辑----- -------------------------------------------------- 进一步的研究表明，这可能是因为我在Android上下文之外尝试Android框架？这可能是真的 - 因为我使用的是课而不是活动？如果是这样我怎么能绕过这个？

Answer 1

这在我看来是TextToSpeech（TTS）的标准示例，可以在互联网上找到它，它应该没有任何问题。（但是，这并不意味着此代码示例没有任何设计问题。）

也许您使用的Android版本太旧或者手机上的TTS设置不正确？你有没有在手机上查看TTS的设置？（通常情况下，如果您的手机上没有正确设置TTS，这段代码应该调用正确的安装页面来执行此操作，但我记得有一条消息说这部分有时会炸毁。）

使用txtText初始化后，您还应检查findViewById()是否为空。

Answer 2

我就是这样做的。

public class TextToSpeechActivity extends Activity implements TextToSpeech.OnInitListener
{
private TextToSpeech mTts;
// This code can be any value you want, its just a checksum.
private static final int MY_DATA_CHECK_CODE = 1234;

/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

// Fire off an intent to check if a TTS engine is installed
Intent checkIntent = new Intent();
checkIntent.setAction(TextToSpeech.Engine.ACTION_CHECK_TTS_DATA);
startActivityForResult(checkIntent, MY_DATA_CHECK_CODE);

}

public void speakClicked(View v)
{
// grab the contents of the text box.
EditText editText = (EditText) findViewById(R.id.inputText);

mTts.speak(editText.getText().toString(),TextToSpeech.QUEUE_FLUSH, null);
}

public void onInit(int i)
{

}
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
if (requestCode == MY_DATA_CHECK_CODE)
{
if (resultCode == TextToSpeech.Engine.CHECK_VOICE_DATA_PASS)
{
// success, create the TTS instance
mTts = new TextToSpeech(this, this);
}
else
{
// missing data, install it
Intent installIntent = new Intent();
installIntent.setAction(
TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
startActivity(installIntent);
}
}
}

@Override
public void onDestroy()
{
if (mTts != null)
{
mTts.stop();
mTts.shutdown();
}
super.onDestroy();
}
}

TextToSpeech抛出一个未知的异常

2 个答案: