Android中的录音机

在Android平台上，我们可以使用录音机来录制音频。录音机是一种非常常见的功能，通常用于开发语音记录、音频拨号、语音识别等应用程序。本文将介绍如何在Android应用程序中使用录音机。

1. 添加权限

在使用录音机之前，我们需要在AndroidManifest.xml文件中添加相应的权限。这样才能够获取到录音机的硬件资源并进行录音操作。

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

2. 检查权限

在Android 6.0及以上版本中，需要动态申请权限。我们在应用程序启动时需要检查是否已经获得了录音所需的权限。

private static final int REQUEST_RECORD_AUDIO_PERMISSION = 200;
private boolean permissionToRecordAccepted = false;
private String[] permissions = {Manifest.permission.RECORD_AUDIO, Manifest.permission.WRITE_EXTERNAL_STORAGE};

private void checkPermissions() {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED
            || ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, permissions, REQUEST_RECORD_AUDIO_PERMISSION);
    } else {
        permissionToRecordAccepted = true;
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    switch (requestCode) {
        case REQUEST_RECORD_AUDIO_PERMISSION:
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                permissionToRecordAccepted = true;
            }
            break;
    }
    if (!permissionToRecordAccepted) {
        // 权限未被授予，处理相应逻辑
    }
}

3. 录音操作

使用录音机进行录音的步骤如下：

3.1 准备录音

private MediaRecorder mediaRecorder;
private String recordFilePath;

private void prepareRecording() {
    // 创建录音机实例
    mediaRecorder = new MediaRecorder();

    // 设置音源为麦克风
    mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);

    // 设置输出格式为3gp
    mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);

    // 设置音频编码器为AMR_NB
    mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

    // 设置录音保存路径
    recordFilePath = getExternalCacheDir().getAbsolutePath() + "/record.3gp";
    mediaRecorder.setOutputFile(recordFilePath);

    try {
        // 准备录音
        mediaRecorder.prepare();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

3.2 开始录音

private void startRecording() {
    if (mediaRecorder != null) {
        // 开始录音
        mediaRecorder.start();
    }
}

3.3 停止录音

private void stopRecording() {
    if (mediaRecorder != null) {
        // 停止录音
        mediaRecorder.stop();
        // 释放录音机资源
        mediaRecorder.release();
        mediaRecorder = null;
    }
}

示例代码

下面是一个简单的示例，展示了如何使用录音机进行录音：

public class MainActivity extends AppCompatActivity {

    private static final int REQUEST_RECORD_AUDIO_PERMISSION = 200;
    private boolean permissionToRecordAccepted = false;
    private String[] permissions = {Manifest.permission.RECORD_AUDIO, Manifest.permission.WRITE_EXTERNAL_STORAGE};
  
    private MediaRecorder mediaRecorder;
    private String recordFilePath;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        checkPermissions();
  
        Button startButton = findViewById(R.id.start_button);
        startButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                prepareRecording();
                startRecording();
            }
        });
  
        Button stopButton = findViewById(R.id.stop_button);
        stopButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopRecording();
            }
        });
    }
  
    private void checkPermissions() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED
                || ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, permissions, REQUEST_RECORD_AUDIO_PERMISSION);
        } else {
            permissionToRecordAccepted = true;
        }
    }
  
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case REQUEST_RECORD_AUDIO_PERMISSION:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    permissionToRecordAccepted = true;
                }
                break;
        }
        if (!permissionToRecordAccepted) {
            // 权限未被授予，处理相应逻辑
        }
    }
  
    private void prepareRecording() {
        mediaRecorder = new MediaRecorder();
        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        recordFilePath = getExternalCacheDir().getAbsolutePath() + "/record.3gp";
        mediaRecorder.setOutputFile(recordFilePath);
        try {
            mediaRecorder.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
  
    private void startRecording() {
        if (mediaRecorder != null) {
            mediaRecorder.start();
            Toast.makeText(this, "开始录音", Toast.LENGTH_SHORT).show();
        }
    }
  
    private void stopRecording() {
        if (mediaRecorder != null) {
            mediaRecorder.stop();
            mediaRecorder.release();
            mediaRecorder = null;
            Toast.makeText(this, "录音结束", Toast.LENGTH_SHORT).show();
        }
    }
}

这是一个简单的Android录音机示例，展示了如何使用录音机进行录音操作。通过检查和申请相应权限，准备录音，开始录音和停止录音，我们可以很容易地在Android应用程序中实现录音功能。

以上就是Android中录音机的介绍及使用示例。希望对你有所帮助！