问题描述
不幸的是，在我的智能手机上，我看到一条消息，提示该应用已停止。
然后我在LogCat中看到了以下错误：
07-19 14:32:48.438: D/ContextHelper(9232): convertTheme. context->name=com.example.texttospeechapp themeResourceId=2131427621
07-19 14:32:48.455: I/PhoneWindow(9232): [generateLayout] setColorNavigationBar => color=0x ff000001
07-19 14:32:48.470: D/PhoneWindowEx(9232): [LMJ][PWEx][generateLayout] setNavigationBarColor2 : colors=0xff000000
07-19 14:32:48.470: I/PhoneWindow(9232): [setNavigationBarColor2] color=0x ff000000
07-19 14:32:48.603: D/AndroidRuntime(9232): Shutting down VM
07-19 14:32:48.603: D/AndroidRuntime(9232): --------- beginning of crash
07-19 14:32:48.605: E/AndroidRuntime(9232): FATAL EXCEPTION: main
07-19 14:32:48.605: E/AndroidRuntime(9232): Process: com.example.texttospeechapp, PID: 9232
07-19 14:32:48.605: E/AndroidRuntime(9232): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.texttospeechapp/com.example.texttospeechapp.MainActivity}: java.lang.ClassCastException: com.example.texttospeechapp.MainActivity cannot be cast to android.speech.tts.TextToSpeech$OnInitListener
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2367)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.ActivityThread.access$800(ActivityThread.java:148)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.os.Handler.dispatchMessage(Handler.java:102)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.os.Looper.loop(Looper.java:135)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.ActivityThread.main(ActivityThread.java:5274)
07-19 14:32:48.605: E/AndroidRuntime(9232): at java.lang.reflect.Method.invoke(Native Method)
07-19 14:32:48.605: E/AndroidRuntime(9232): at java.lang.reflect.Method.invoke(Method.java:372)
07-19 14:32:48.605: E/AndroidRuntime(9232): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909)
07-19 14:32:48.605: E/AndroidRuntime(9232): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
07-19 14:32:48.605: E/AndroidRuntime(9232): Caused by: java.lang.ClassCastException: com.example.texttospeechapp.MainActivity cannot be cast to android.speech.tts.TextToSpeech$OnInitListener
07-19 14:32:48.605: E/AndroidRuntime(9232): at com.example.texttospeechapp.MainActivity.onCreate(MainActivity.java:27)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.Activity.performCreate(Activity.java:5977)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
07-19 14:32:48.605: E/AndroidRuntime(9232): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2258)
07-19 14:32:48.605: E/AndroidRuntime(9232): ... 10 more
07-19 14:32:54.720: I/Process(9232): Sending signal. PID: 9232 SIG: 9
这是我在MainActivity.java中的代码
package com.example.texttospeechapp;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.support.v7.app.ActionBarActivity;
import java.util.Locale;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends ActionBarActivity {
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextToSpeech tts = new TextToSpeech(this,(OnInitListener) this);
tts.setLanguage(Locale.US);
tts.speak("Text to say aloud", TextToSpeech.QUEUE_ADD, null);
}
@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);
}
}
我的代码没有任何错误。 9条警告，但无错误。
解决：这是一个有效的代码：
package com.example.texttospeechapp;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.support.v7.app.ActionBarActivity;
import java.util.Locale;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends ActionBarActivity implements OnInitListener {
private static final int MY_DATA_CHECK_CODE = 0;
TextToSpeech mTts;
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
//tts = new TextToSpeech(this,(OnInitListener) this);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initTTS();
}
@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);
}
private void initTTS() {
Intent checkIntent = new Intent();
checkIntent.setAction(TextToSpeech.Engine.ACTION_CHECK_TTS_DATA);
startActivityForResult(checkIntent, MY_DATA_CHECK_CODE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(requestCode == MY_DATA_CHECK_CODE) {
if(resultCode == TextToSpeech.Engine.CHECK_VOICE_DATA_PASS) {
mTts = new TextToSpeech(this, this);
} else {
Intent installIntent = new Intent();
installIntent.setAction(TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
startActivity(installIntent);
}
}
}
public void onInit(int status) {
if(status == TextToSpeech.SUCCESS) {
int result = mTts.setLanguage(Locale.US);
if(result == TextToSpeech.LANG_AVAILABLE
|| result == TextToSpeech.LANG_COUNTRY_AVAILABLE) {
mTts.speak("Start system", TextToSpeech.QUEUE_FLUSH, null);
}
}
}
}
1楼
==== 问题 ====
您在MainActivity的这一行上收到ClassCastException：
TextToSpeech tts = new TextToSpeech(this,(OnInitListener) this);
那是因为您正在将this （对活动的引用）转换为OnInitListener。
通过应用强制转换，您已经告诉编译器this是OnInitListener的实例。
这就是为什么您没有得到编译错误的原因。
但是，将在运行时检查强制类型转换，当VM确定that 不是该接口的实例时，它将失败。
因此，出现以下LogCat消息：
java.lang.ClassCastException：com.example.texttospeechapp.MainActivity无法转换为android.speech.tts.TextToSpeech $ OnInitListener
==== 解决方案 ====
要解决此问题，您必须在活动中实现该接口，如下所示
public class MainActivity extends ActionBarActivity implements OnInitListener {
然后您将需要在活动中实现一个OnInitListner方法：
public void onInit (int status) {
// This will be called when the text-to-speech engine has been initialized.
}