android MediaCodec 录屏时长和大小功能实现完整代码

以下是一个简单的 Android MediaCodec 录屏实现的完整代码示例，可以记录屏幕并保存为 MP4 文件。

public class ScreenRecorder {
    private static final String TAG = "ScreenRecorder";

    private static final String MIME_TYPE = "video/avc";
    private static final int FRAME_RATE = 30; // 帧率
    private static final int I_FRAME_INTERVAL = 1; // I 帧间隔
    private static final int BIT_RATE = 6000000; // 比特率
    private static final int REQUEST_CODE = 1;

    private static int width;
    private static int height;
    private static int dpi;

    private MediaProjection mediaProjection;
    private MediaCodec mediaCodec;
    private MediaMuxer mediaMuxer;
    private Surface surface;
    private VirtualDisplay virtualDisplay;

    private boolean isRecording;

    private String outputFilePath;

    private Context context;

    public ScreenRecorder(Context context) {
        this.context = context;
    }

    public void startRecording(int resultCode, Intent data) {
        if (isRecording) {
            Log.e(TAG, "Already recording");
            return;
        }

        mediaProjection = createMediaProjection(resultCode, data);
        if (mediaProjection == null) {
            Log.e(TAG, "MediaProjection is null");
            return;
        }

        width = context.getResources().getDisplayMetrics().widthPixels;
        height = context.getResources().getDisplayMetrics().heightPixels;
        dpi = context.getResources().getDisplayMetrics().densityDpi;

        mediaCodec = createMediaCodec();
        mediaMuxer = createMediaMuxer();

        mediaCodec.start();
        virtualDisplay = createVirtualDisplay();
        isRecording = true;
    }

    public void stopRecording() {
        if (!isRecording) {
            Log.e(TAG, "Not recording");
            return;
        }

        isRecording = false;

        if (virtualDisplay != null) {
            virtualDisplay.release();
            virtualDisplay = null;
        }

        if (mediaCodec != null) {
            mediaCodec.stop();
            mediaCodec.release();
            mediaCodec = null;
        }

        if (mediaProjection != null) {
            mediaProjection.stop();
            mediaProjection = null;
        }

        if (mediaMuxer != null) {
            mediaMuxer.stop();
            mediaMuxer.release();
            mediaMuxer = null;
        }
    }

    private MediaProjection createMediaProjection(int resultCode, Intent data) {
        return ((MediaProjectionManager) context.getSystemService(Context.MEDIA_PROJECTION_SERVICE))
                .getMediaProjection(resultCode, data);
    }

    private MediaCodec createMediaCodec() {
        MediaFormat format = MediaFormat.createVideoFormat(MIME_TYPE, width, height);
        format.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface);
        format.setInteger(MediaFormat.KEY_BIT_RATE, BIT_RATE);
        format.setInteger(MediaFormat.KEY_FRAME_RATE, FRAME_RATE);
        format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, I_FRAME_INTERVAL);

        MediaCodec codec = null;
        try {
            codec = MediaCodec.createEncoderByType(MIME_TYPE);
            codec.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
            surface = codec.createInputSurface();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return codec;
    }

    private MediaMuxer createMediaMuxer() {
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss", Locale.US);
        String dateTime = dateFormat.format(new Date());
        String fileName = "screen_record_" + dateTime + ".mp4";
        outputFilePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES)
                + File.separator + fileName;

        MediaMuxer muxer = null;
        try {
            muxer = new MediaMuxer(outputFilePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
        } catch (IOException e) {
            e.printStackTrace();
        }

        return muxer;
    }

    private VirtualDisplay createVirtualDisplay() {
        return mediaProjection.createVirtualDisplay(TAG, width, height, dpi,
                DisplayManager.VIRTUAL_DISPLAY_FLAG_PUBLIC, surface, null, null);
    }

    public boolean isRecording() {
        return isRecording;
    }

    public String getOutputFilePath() {
        return outputFilePath;
    }
}

使用该类，你只需要在你的 Activity 中调用 startRecording() 方法来开始录制，调用 stopRecording() 方法来停止录制。录制完成后，你可以通过调用 getOutputFilePath() 方法来获得输出文件的路径。

以下是一个简单的使用示例：

public class MainActivity extends AppCompatActivity {
    private static final int REQUEST_CODE = 1;

    private ScreenRecorder screenRecorder;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        screenRecorder = new ScreenRecorder(this);
        findViewById(R.id.start_button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startRecording();
            }
        });
        findViewById(R.id.stop_button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopRecording();
            }
        });
    }

    private void startRecording() {
        Intent mediaProjectionIntent = ((MediaProjectionManager) getSystemService(Context.MEDIA_PROJECTION_SERVICE))
                .createScreenCaptureIntent();
        startActivityForResult(mediaProjectionIntent, REQUEST_CODE);
    }

    private void stopRecording() {
        screenRecorder.stopRecording();
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE && resultCode == RESULT_OK && data != null) {
            screenRecorder.startRecording(resultCode, data);
        }
    }
}

补充说明：该代码仅仅是一个简单的示例，可能存在许多潜在问题和优化空间。请在实际使用中自行测试和改进。