更改方法后全局变量保持不变

Question

我目前面临一个小挑战，我无法在更改全局变量 (fileName) 的方法 (startRecording()) 之外获取对其所做的更改。

现在发生的情况：文件名在被 startRecording() 更改后仍然为空

我想要的是：在 userRecordButton 的 onClick 中获取文件名

这看起来像是一个基本问题，但我无法解决，如果能得到一些快速帮助会很有帮助。先感谢您。

p/s：这只是我认为相关的部分代码，如果您需要完整代码，请通知我。

代码

    public class WordAdapter extends ArrayAdapter<Word> { 
public String mFileName = null;

@Override
    public View getView(int position, View convertView, ViewGroup parent) {

final Button userRecordButton = (Button)listItemView.findViewById(R.id.recordButton);

userRecordButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {      
                    if (!isRecording) {
                        userRecordButton.setText("Ready?");
                        Handler delayRecord = new Handler();
                      //This is where i called the handler
                        setDelayedRecord(delayRecord, userPlayButton, userRecordButton);

            //The issue is here: it shows null when i tried debugging
                        String whatIsMyFileName = mFileName;

                        Handler maximumRecord = new Handler();
                        setMaximumRecord(maximumRecord, userPlayButton, userRecordButton);
                    } else {
                        exeStopRecording(userPlayButton, userRecordButton);
                    }
                }
            }
        });

} //End of getView

    public void setDelayedRecord(Handler handler, final Button userPlayBtnReference, final Button userRecordBtnReference) {
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                try {
                    //James!, this is where I called start recorder.
                    startRecording();
                    userPlayBtnReference.setEnabled(false);
                } catch (IllegalStateException e) {
                    Log.d("Hello", "Problem in start recording", e);
                }
                userRecordBtnReference.setText("Stop");
                Toast.makeText(mContext, "Started Recording", Toast.LENGTH_SHORT).show();
                setPathName(mFileName);
            }
        }, 500);
    }

 private void startRecording() {

        mFile = new File(Environment.getExternalStorageDirectory(), mFolder_main);
        if (!mFile.exists()) {
            mFile.mkdirs();
        }

        formatter = new SimpleDateFormat("yyMMdd'-'HHmmssSSS");
        currentTime_1 = new Date();
        dateString = formatter.format(currentTime_1);
        uniqueName = "Pronunce-" + dateString + ".3gp";
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/" + mFolder_main + "/" + uniqueName;
    //mFileName should no longer be null    

        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(mFileName);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

        try {
            mRecorder.prepare();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }
        isRecording = true;
        mRecorder.start();
    }

}//End of wordAdapter

Answer 1

您有一个全局变量 mFileName，它已设置为 null。然后进入事件处理程序并将一个新的局部变量 whatIsMyFileName 设置为全局变量 null 的值。事件处理程序中的任何时候都不会调用任何会更改局部或全局变量值的方法。