自动录制音频

Question

import java.io.File;
import java.io.IOException;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class AudioRecordingActivity extends Activity {
    private static final String AUDIO_RECORDER_FILE_EXT_3GP = ".3gp";
    private static final String AUDIO_RECORDER_FILE_EXT_MP4 = ".mp4";
private static final String AUDIO_RECORDER_FOLDER = "AudioRecorder";

private MediaRecorder recorder = null;
private int currentFormat = 0;
private int output_formats[] = { MediaRecorder.OutputFormat.MPEG_4 };
private String file_exts[] = { AUDIO_RECORDER_FILE_EXT_MP4};

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

    setButtonHandlers();
    enableButtons(false);
    //setFormatButtonCaption();
}

private void setButtonHandlers() {
    ((Button) findViewById(R.id.btnStart)).setOnClickListener(btnClick);
    ((Button) findViewById(R.id.btnStop)).setOnClickListener(btnClick);
    //((Button) findViewById(R.id.btnFormat)).setOnClickListener(btnClick);
}

private void enableButton(int id, boolean isEnable) {
    ((Button) findViewById(id)).setEnabled(isEnable);
}

private void enableButtons(boolean isRecording) {
    enableButton(R.id.btnStart, !isRecording);
    //enableButton(R.id.btnFormat, !isRecording);
    enableButton(R.id.btnStop, isRecording);
}

/*private void setFormatButtonCaption() {
    ((Button) findViewById(R.id.btnFormat))
            .setText(getString(R.string.audio_format) + " ("
                    + file_exts[currentFormat] + ")");
}*/

private String getFilename() {
    String filepath = Environment.getExternalStorageDirectory().getPath();
    File file = new File(filepath, AUDIO_RECORDER_FOLDER);

    if (!file.exists()) {
        file.mkdirs();
    }

    return (file.getAbsolutePath() + "/" + System.currentTimeMillis() + file_exts[currentFormat]);
}

private void startRecording() {
    recorder = new MediaRecorder();

    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    recorder.setOutputFormat(output_formats[currentFormat]);
    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    recorder.setOutputFile(getFilename());

    recorder.setOnErrorListener(errorListener);
    recorder.setOnInfoListener(infoListener);

    try {
        recorder.prepare();
        recorder.start();
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

private void stopRecording() {
    if (null != recorder) {
        recorder.stop();
        recorder.reset();
        recorder.release();

        recorder = null;
    }
}

private void displayFormatDialog() {
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    String formats[] = { "MPEG 4", "3GPP" };

    builder.setTitle(getString(R.string.choose_format_title))
            .setSingleChoiceItems(formats, currentFormat,
                    new DialogInterface.OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog,
                                int which) {
                            currentFormat = which;
                            //setFormatButtonCaption();

                            dialog.dismiss();
                        }
                    }).show();
}

private MediaRecorder.OnErrorListener errorListener = new MediaRecorder.OnErrorListener() {
    @Override
    public void onError(MediaRecorder mr, int what, int extra) {
        Toast.makeText(AudioRecordingActivity.this,
                "Error: " + what + ", " + extra, Toast.LENGTH_SHORT).show();
    }
};

private MediaRecorder.OnInfoListener infoListener = new MediaRecorder.OnInfoListener() {
    @Override
    public void onInfo(MediaRecorder mr, int what, int extra) {
        Toast.makeText(AudioRecordingActivity.this,
                "Warning: " + what + ", " + extra, Toast.LENGTH_SHORT)
                .show();
    }
};

private View.OnClickListener btnClick = new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.btnStart: {
            Toast.makeText(AudioRecordingActivity.this, "Start Recording",
                    Toast.LENGTH_SHORT).show();

            enableButtons(true);
            startRecording();

            break;
        }
        case R.id.btnStop: {
            Toast.makeText(AudioRecordingActivity.this, "Stop Recording",
                    Toast.LENGTH_SHORT).show();
            enableButtons(false);
            stopRecording();

            break;
        }
        /*case R.id.btnFormat: {
            displayFormatDialog();

            break;
        }*/
        }
    }
};
}

以上代码记录音频并在点击按钮时将其存储在SD卡中以开始和停止录制。

我想制作一个录音机应用程序，在启动应用程序时自动开始录制音频约30秒。是否可以这样做？如果是，那怎么样？

Answer 1

您可以在应用的onCreate或onResume方法中发出延迟任务，该方法将在30秒后开始录制。

如果要限制录制时间，请在录制开始后发出延迟任务。

之前询问有关延迟任务的问题：How to call a method after a delay in Android

您还可以在此处查看更多信息：Handler vs AsyncTask