多媒体——音频——利用MediaRecorder录制音频

梦里梦外; 2024-04-03 09:16 42阅读 0赞

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布局：

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MediaUtil

package com.example.myapplication.util;
    
    import android.annotation.SuppressLint;
    import android.content.Context;
    import android.graphics.Bitmap;
    import android.media.MediaMetadataRetriever;
    import android.net.Uri;
    import android.os.Environment;
    import android.util.Log;
    
    import java.io.File;
    
    @SuppressLint("DefaultLocale")
    public class MediaUtil {
        private final static String TAG = "MediaUtil";
    
        // 格式化播放时长(mm:ss)
        public static String formatDuration(int milliseconds) {
            int seconds = milliseconds / 1000;
            int hour = seconds / 3600;
            int minute = seconds / 60;
            int second = seconds % 60;
            String str;
            if (hour > 0) {
                str = String.format("%02d:%02d:%02d", hour, minute, second);
            } else {
                str = String.format("%02d:%02d", minute, second);
            }
            return str;
        }
    
        // 获得音视频文件的缓存路径
        public static String getRecordFilePath(Context context, String dir_name, String extend_name) {
            String path = "";
            File recordDir = new File(context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS).toString() + "/" + dir_name + "/");
            if (!recordDir.exists()) {
                recordDir.mkdirs();
            }
            try {
                File recordFile = File.createTempFile(DateUtil.getNowDateTime(), extend_name, recordDir);
                path = recordFile.getAbsolutePath();
                Log.d(TAG, "dir_name=" + dir_name + ", extend_name=" + extend_name + ", path=" + path);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return path;
        }
    
        // 获取视频文件中的某帧图片
        public static Bitmap getOneFrame(Context ctx, Uri uri) {
            MediaMetadataRetriever retriever = new MediaMetadataRetriever();
            retriever.setDataSource(ctx, uri);
            // 获得视频的播放时长，大于1秒的取第1秒处的帧图，不足1秒的取第0秒处的帧图
            String duration = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
            Log.d(TAG, "duration="+duration);
            int pos = (Integer.parseInt(duration)/1000)>1 ? 1 : 0;
            // 获取指定时间的帧图，注意getFrameAtTime方法的时间单位是微秒
            return retriever.getFrameAtTime(pos * 1000 * 1000);
        }
    }

item_select.xml

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主代码：

package com.example.myapplication;
    
    import android.media.AudioManager;
    import android.media.MediaPlayer;
    import android.media.MediaRecorder;
    import android.os.Bundle;
    import android.text.TextUtils;
    import android.util.Log;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ArrayAdapter;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.LinearLayout;
    import android.widget.ProgressBar;
    import android.widget.Spinner;
    import android.widget.TextView;
    import android.widget.Toast;
    import com.example.myapplication.util.MediaUtil;
    import androidx.appcompat.app.AppCompatActivity;
    import java.util.Timer;
    import java.util.TimerTask;
    
    public class MainActivity extends AppCompatActivity implements View.OnClickListener, MediaRecorder.OnInfoListener {
        private static final String TAG = "MediaRecorderActivity";
        private Button btn_record;
        private LinearLayout ll_progress;
        private ProgressBar pb_record; // 声明一个进度条对象
        private TextView tv_progress;
        private ImageView iv_audio; // 该图标充当播放按钮
        private MediaRecorder mMediaRecorder = new MediaRecorder(); // 媒体录制器
        private boolean isRecording = false; // 是否正在录制
        private int mAudioEncoder; // 音频编码
        private int mOutputFormat; // 输出格式
        private int mDuration; // 录制时长
        private String mRecordFilePath; // 录制文件的保存路径
        private Timer mTimer = new Timer(); // 计时器
        private int mTimeCount; // 时间计数
        private MediaPlayer mMediaPlayer = new MediaPlayer(); // 媒体播放器
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            btn_record = findViewById(R.id.btn_record);
            ll_progress = findViewById(R.id.ll_progress);
            pb_record = findViewById(R.id.pb_record);
            tv_progress = findViewById(R.id.tv_progress);
            iv_audio = findViewById(R.id.iv_audio);
            btn_record.setOnClickListener(this);
            iv_audio.setOnClickListener(this);
            initEncoderSpinner(); // 初始化音频编码的下拉框
            initFormatSpinner(); // 初始化输出格式的下拉框
            initDurationSpinner(); // 初始化录制时长的下拉框
        }
    
        // 初始化音频编码的下拉框
        private void initEncoderSpinner() {
            ArrayAdapter<String> encoderAdapter = new ArrayAdapter<String>(this,
                    R.layout.item_select, encoderDescArray);
            Spinner sp_encoder = findViewById(R.id.sp_encoder);
            sp_encoder.setPrompt("请选择音频编码"); // 设置下拉框的标题
            sp_encoder.setAdapter(encoderAdapter); // 设置下拉框的数组适配器
            // 给下拉框设置选择监听器，一旦用户选中某一项，就触发监听器的onItemSelected方法
            sp_encoder.setOnItemSelectedListener(new EncoderSelectedListener());
            sp_encoder.setSelection(0); // 设置下拉框默认显示第一项
        }
    
        private String[] encoderDescArray = {
                "默认编码",
                "窄带编码",
                "宽带编码",
                "低复杂度的高级编码",
                "高效率的高级编码",
                "增强型低延时的高级编码"
        };
        private int[] encoderArray = {
                MediaRecorder.AudioEncoder.DEFAULT,
                MediaRecorder.AudioEncoder.AMR_NB,
                MediaRecorder.AudioEncoder.AMR_WB,
                MediaRecorder.AudioEncoder.AAC,
                MediaRecorder.AudioEncoder.HE_AAC,
                MediaRecorder.AudioEncoder.AAC_ELD
        };
    
        class EncoderSelectedListener implements AdapterView.OnItemSelectedListener {
            public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                mAudioEncoder = encoderArray[arg2];
            }
    
            public void onNothingSelected(AdapterView<?> arg0) {}
        }
    
        // 初始化输出格式的下拉框
        private void initFormatSpinner() {
            ArrayAdapter<String> formatAdapter = new ArrayAdapter<String>(this,
                    R.layout.item_select, formatDescArray);
            Spinner sp_format = findViewById(R.id.sp_format);
            sp_format.setPrompt("请选择输出格式"); // 设置下拉框的标题
            sp_format.setAdapter(formatAdapter); // 设置下拉框的数组适配器
            sp_format.setSelection(0); // 设置下拉框默认显示第一项
            // 给下拉框设置选择监听器，一旦用户选中某一项，就触发监听器的onItemSelected方法
            sp_format.setOnItemSelectedListener(new FormatSelectedListener());
        }
    
        private String[] formatDescArray = {
                "默认格式",
                "窄带格式",
                "宽带格式",
                "高级的音频传输流格式"
        };
        private int[] formatArray = {
                MediaRecorder.OutputFormat.DEFAULT,
                MediaRecorder.OutputFormat.AMR_NB,
                MediaRecorder.OutputFormat.AMR_WB,
                MediaRecorder.OutputFormat.AAC_ADTS
        };
        class FormatSelectedListener implements AdapterView.OnItemSelectedListener {
            public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                mOutputFormat = formatArray[arg2];
            }
    
            public void onNothingSelected(AdapterView<?> arg0) {}
        }
    
        // 初始化录制时长的下拉框
        private void initDurationSpinner() {
            ArrayAdapter<String> durationAdapter = new ArrayAdapter<String>(this,
                    R.layout.item_select, durationDescArray);
            Spinner sp_duration = findViewById(R.id.sp_duration);
            sp_duration.setPrompt("请选择录制时长"); // 设置下拉框的标题
            sp_duration.setAdapter(durationAdapter); // 设置下拉框的数组适配器
            sp_duration.setSelection(0); // 设置下拉框默认显示第一项
            // 给下拉框设置选择监听器，一旦用户选中某一项，就触发监听器的onItemSelected方法
            sp_duration.setOnItemSelectedListener(new DurationSelectedListener());
        }
    
        private String[] durationDescArray = {"5秒", "10秒", "20秒", "30秒", "60秒"};
        private int[] durationArray = {5, 10, 20, 30, 60};
        class DurationSelectedListener implements AdapterView.OnItemSelectedListener {
            public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                mDuration = durationArray[arg2];
            }
    
            public void onNothingSelected(AdapterView<?> arg0) {}
        }
    
        @Override
        public void onClick(View v) {
            if (v.getId() == R.id.btn_record) {
                if (!isRecording) { // 未在录音
                    startRecord(); // 开始录音
                } else { // 正在录音
                    stopRecord(); // 停止录音
                }
            } else if (v.getId() == R.id.iv_audio) {
                mMediaPlayer.reset(); // 重置媒体播放器
                mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC); // 设置音频流的类型为音乐
                try {
                    mMediaPlayer.setDataSource(mRecordFilePath); // 设置媒体数据的文件路径
                    mMediaPlayer.prepare(); // 媒体播放器准备就绪
                    mMediaPlayer.start(); // 媒体播放器开始播放
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    
        // 开始录音
        private void startRecord() {
            Log.d(TAG, "startRecord mAudioEncoder="+mAudioEncoder+", mOutputFormat="+mOutputFormat+", mDuration="+mDuration);
            ll_progress.setVisibility(View.VISIBLE);
            isRecording = !isRecording;
            btn_record.setText("停止录制");
            pb_record.setMax(mDuration); // 设置进度条的最大值
            mTimeCount = 0; // 时间计数清零
            mTimer = new Timer(); // 创建一个计时器
            mTimer.schedule(new TimerTask() {
                @Override
                public void run() {
                    pb_record.setProgress(mTimeCount); // 设置进度条的当前进度
                    tv_progress.setText(MediaUtil.formatDuration(mTimeCount*1000));
                    mTimeCount++;
                }
            }, 0, 1000); // 计时器每隔一秒就更新进度条上的录制进度
            // 获取本次录制的媒体文件路径
            mRecordFilePath = MediaUtil.getRecordFilePath(this, "RecordAudio", ".amr");
            // 下面是媒体录制器的处理代码
            mMediaRecorder.reset(); // 重置媒体录制器
            mMediaRecorder.setOnInfoListener(this); // 设置媒体录制器的信息监听器
            mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); // 设置音频源为麦克风
            mMediaRecorder.setOutputFormat(mOutputFormat); // 设置媒体的输出格式。该方法要先于setAudioEncoder调用
            mMediaRecorder.setAudioEncoder(mAudioEncoder); // 设置媒体的音频编码器
            // mMediaRecorder.setAudioSamplingRate(8); // 设置媒体的音频采样率。可选
            // mMediaRecorder.setAudioChannels(2); // 设置媒体的音频声道数。可选
            // mMediaRecorder.setAudioEncodingBitRate(1024); // 设置音频每秒录制的字节数。可选
            mMediaRecorder.setMaxDuration(mDuration * 1000); // 设置媒体的最大录制时长
            // mMediaRecorder.setMaxFileSize(1024*1024*10); // 设置媒体的最大文件大小
            // setMaxFileSize与setMaxDuration设置其一即可
            mMediaRecorder.setOutputFile(mRecordFilePath); // 设置媒体文件的保存路径
            try {
                mMediaRecorder.prepare(); // 媒体录制器准备就绪
                mMediaRecorder.start(); // 媒体录制器开始录制
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        // 停止录音
        private void stopRecord() {
            isRecording = !isRecording;
            btn_record.setText("开始录制");
            mTimer.cancel(); // 取消定时器
            mMediaRecorder.stop(); // 媒体录制器停止录制
        }
    
        @Override
        public void onInfo(MediaRecorder mr, int what, int extra) {
            // 录制达到最大时长，或者达到文件大小限制，都停止录制
            if (what == MediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
                    || what == MediaRecorder.MEDIA_RECORDER_INFO_MAX_FILESIZE_REACHED) {
                stopRecord(); // 停止录音
                iv_audio.setVisibility(View.VISIBLE);
                Toast.makeText(this, "已结束录制，音频文件路径为"+mRecordFilePath, Toast.LENGTH_LONG).show();
            }
        }
    
        @Override
        protected void onStop() {
            super.onStop();
            if (!TextUtils.isEmpty(mRecordFilePath) && isRecording) {
                stopRecord(); // 停止录音
            }
            if (mMediaPlayer.isPlaying()) { // 如果正在播放
                mMediaPlayer.stop(); // 停止播放
            }
        }
    
        @Override
        protected void onDestroy() {
            super.onDestroy();
            mMediaRecorder.release(); // 释放媒体录制器
            mMediaPlayer.release(); // 释放媒体播放器
        }
    }

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