Question

这是我在播放音频文件时遇到的异常问题。在我的混乱的文字游戏应用程序中，我有两个声音文件，即。 clap.mp3和oops.mp3。当用户分别提供正确答案和错误答案时，将播放这些文件。当用户提供正确答案时，播放音频文件clap.mp3并向用户提供下一个谜题。现在当用户提供错误的答案时，它应该播放oops.mp3。但我的应用程序，给出了一个ANR消息，要求我“强制关闭”它。请帮帮我。

代码：

public void checkWord()
{
    if(abcd.equalsIgnoreCase(etGuessedWord.getText().toString()))
    {
        WordLibrary.setMyInt(WordLibrary.getMyInt() + 10);
        tvScore.setText(String.valueOf(WordLibrary.getMyInt()));
        mp = MediaPlayer.create(this, R.raw.clap);
        mp.start();
        new AlertDialog.Builder(JumbledWords.this).setMessage("Awesome!!!") 
        .setPositiveButton("OK", new DialogInterface.OnClickListener() { 

        @Override 
        public void onClick(DialogInterface dialog, int which) { 
        // TODO Auto-generated method stub 
            wordIdx = (wordIdx + 1) % getSize();
            sWord = getScrambledWord(word_list[wordIdx]);
            tvScrambledWord.setText(sWord);
            abcd = word_list[wordIdx];
            ++word_array_length;
            mp.stop();
            etGuessedWord.setText("");

            if(word_array_length >= word_list.length)
            {
                new AlertDialog.Builder(JumbledWords.this).setMessage("Level Complete!!! ")
                .setPositiveButton("OK", new DialogInterface.OnClickListener() { 

                @Override 
                public void onClick(DialogInterface dialog, int which) { 
                // TODO Auto-generated method stub 
                    start = 0;
                    finish();           
                } 
                }).create().show();     
            }


        } 
        }).create().show();



    }
    else
    {
        mp = MediaPlayer.create(this, R.raw.oop);
        mp.start();
        new AlertDialog.Builder(JumbledWords.this).setMessage("Wrong. Try Again")
        .setPositiveButton("OK", new DialogInterface.OnClickListener() { 

        @Override 
        public void onClick(DialogInterface dialog, int which) { 
        // TODO Auto-generated method stub
            mp.stop();
            etGuessedWord.setText("");
        } 
        }).create().show();



    }
}


    etGuessedWord.addTextChangedListener(new TextWatcher(){

        @Override
        public void afterTextChanged(Editable arg0) {
            // TODO Auto-generated method stub
            if(etGuessedWord.getText().toString().length() == abcd.length() )
            {
                checkWord();
            }
        }

        @Override
        public void beforeTextChanged(CharSequence arg0, int arg1,
                int arg2, int arg3) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onTextChanged(CharSequence arg0, int arg1, int arg2,
                int arg3) {
            // TODO Auto-generated method stub

        }

    });

异常消息

java.lang.NullPointerException
at com.myambitionconsultants.JumbledWords.checkWord(JumbledWords.java:447)
at com.myambitionconsultants.JumbledWords$1.afterTextChanged(JumbledWords.java:125)
at android.widget.TextView.sendAfterTextChanged(TextView.java:6281)
at android.widget.TextView$ChangeWatcher.afterTextChanged(TextView.java:6504)
at android.text.SpannableStringBuilder.sendTextHasChanged(SpannableStringBuilder.java:897)
at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:353)
at android.text.SpannableStringBuilder.change(SpannableStringBuilder.java:269)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:432)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:409)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:28)
at android.view.inputmethod.BaseInputConnection.replaceText(BaseInputConnection.java:583)
at android.view.inputmethod.BaseInputConnection.commitText(BaseInputConnection.java:174)
at com.android.internal.widget.EditableInputConnection.commitText(EditableInputConnection.java:120)
at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:247)
at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:73)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:143)
at android.app.ActivityThread.main(ActivityThread.java:4701)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)

Answer 1

Hiiii， Yor正在获取空指针异常意味着您的MediaPlayer可能未初始化。所以你必须先进行初始化。你初始化了吗？比如，mp = new MediaPlayer（）;之后你可以使用

Answer 2

 mp = MediaPlayer.create(this, R.raw.clap);

如果媒体播放器对象创建失败，则返回null。您应该尝试使用不同的数据源，如oops.mp3。这也可能是device related问题。

为什么MediaPlayer对象会发出异常？

2 个答案: