Question

我有一种尝试创建AudioRecord的方法。不同的手机支持不同的采样率，通道配置和音频格式。因此，该方法尝试为每个方法创建AudioRecord并返回第一个有效的方法。

private AudioRecord getAudioRecord() {
    for (int rate: sampleRates) {
        for (int audioFormat: audioFormats) {
            for (int channelConfig: channelConfigs) {
                String description = rate + "Hz, bits: " + audioFormat
                        + ", channel: " + channelConfig;

                Log.d(TAG, "Trying: " + description);

                int bufferSize = AudioRecord.getMinBufferSize(rate, channelConfig, audioFormat);
                if (bufferSize == AudioRecord.ERROR
                        || bufferSize == AudioRecord.ERROR_BAD_VALUE) {
                    Log.d(TAG, "Failed: This rate/channel config/format is not supported");
                    continue;
                }

                AudioRecord recorder = new AudioRecord(AudioSource.MIC, rate, channelConfig, audioFormat, bufferSize);
                if (recorder.getState() == AudioRecord.STATE_UNINITIALIZED) {
                    Log.d(TAG, "Failed: Recorder is uninitialized");
                    continue;
                }

                Log.d(TAG, "Success: " + description);
                return recorder;
            }
        }
    }

    Log.e(TAG, "Failed all rates. Does the device have a microphone?");
    return null;
}

问题是return recorder永远不会发生！

这是我的logcat输出：

Logcat output

在突出显示的行（8000/3/12）上没有错误，但也没有成功。

如果我在下面的评论中没有使用continue，它仍然不会返回！

private AudioRecord getAudioRecord() {
    for (int rate: sampleRates) {
        for (int audioFormat: audioFormats) {
            for (int channelConfig: channelConfigs) {
                String description = rate + "Hz, bits: " + audioFormat
                        + ", channel: " + channelConfig;

                Log.d(TAG, "Trying (2): " + description);

                int bufferSize = AudioRecord.getMinBufferSize(rate, channelConfig, audioFormat);
                if (bufferSize != AudioRecord.ERROR && bufferSize != AudioRecord.ERROR_BAD_VALUE) {
                    AudioRecord recorder = new AudioRecord(AudioSource.MIC, rate, channelConfig, audioFormat, bufferSize);
                    if (recorder.getState() == AudioRecord.STATE_INITIALIZED) {
                        Log.d(TAG, "Success: " + description);
                        return recorder;
                    } else {
                        Log.d(TAG, "Failed: Recorder is uninitialized");
                    }
                } else {
                    Log.d(TAG, "Failed: This rate/channel config/format is not supported");
                }
            }
        }
    }

    Log.e(TAG, "Failed all rates. Does the device have a microphone?");
    return null;
}

Answer 1

return语句没有问题，你根本就没到达它，因为你的AudioRecord永远不会初始化（大多数例子没有检查它，即使它们可能应该检查）

作为简短的完整性检查，您可能需要检查您的清单文件到verify you have the proper permissions以便首先录制音频，因为对麦克风的访问权限可能是/可能不存在。

Answer 2

将您的函数包装在try / catch块中，您可能会发现某些事情导致异常被抛出。

即使没有其他代码分支，我的“return”语句也不起作用

2 个答案: