android实现录屏小功能

//开始录音
  if (mMediaRecorder == null) {
      mMediaRecorder = new MediaRecorder();
    }
    mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.AMR_NB);
    mMediaRecorder.setOutputFile(mRecordFilePath);
    mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);//amr_nb格式头部有6个字节的头信息

    try {
      mMediaRecorder.prepare();
      mMediaRecorder.start();
      isRunning = true;
      AudioUtil.startAudio();
      mHandler.sendEmptyMessageDelayed(MSG_TYPE_COUNT_DOWN, 1000);
    } catch (IOException e) {
      e.printStackTrace();
    }

/**
   * 合成amr_nb编码的音频
   * @param partsPaths
   * @param unitedFilePath
   */
  public static void uniteAMRFile(List<String> partsPaths, String unitedFilePath) {
    try {
      File unitedFile = new File(unitedFilePath);
      FileOutputStream fos = new FileOutputStream(unitedFile);
      RandomAccessFile ra = null;
      for (int i = 0; i < partsPaths.size(); i++) {
        ra = new RandomAccessFile(partsPaths.get(i), "rw");
        if (i != 0) {
          ra.seek(6);
        }
        byte[] buffer = new byte[1024 * 8];
        int len = 0;
        while ((len = ra.read(buffer)) != -1) {
          fos.write(buffer,0,len);
        }
        File file = new File(partsPaths.get(i));
        if(file.exists()){
          file.delete();
        }
      }
      if(ra!=null){
        ra.close();
      }
      fos.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

mediaPlayer = new MediaPlayer();
mediaPlayer.setDataSource(path);
    mediaPlayer.prepare();
   mediaPlayer.start();

public class ForbitLayoutManager extends LinearLayoutManager {
  private boolean canScrollHorizon = true;
  private boolean canScrollVertical = true;
  public ForbitLayoutManager(Context context) {
    super(context);
  }

  public ForbitLayoutManager(Context context, int orientation, boolean reverseLayout) {
    super(context, orientation, reverseLayout);
  }

  public ForbitLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
  }

  public void setCanScrollHorizon(boolean canScrollHorizon) {
    this.canScrollHorizon = canScrollHorizon;
  }

  public void setCanScrollVertical(boolean canScrollVertical) {
    this.canScrollVertical = canScrollVertical;
  }

  @Override
  public boolean canScrollHorizontally() {
    return canScrollHorizon && super.canScrollHorizontally();
  }

  @Override
  public boolean canScrollVertically() {
    return canScrollVertical && super.canScrollVertically();
  }
}

mPagerSnapHelper = new PagerSnapHelper();
mPagerSnapHelper.attachToRecyclerView(recyclerView);

public class RecyclerViewPageChangeListenerHelper extends RecyclerView.OnScrollListener {
  private SnapHelper snapHelper;
  private OnPageChangeListener onPageChangeListener;
  private int oldPosition = -1;//防止同一Position多次触发

  public RecyclerViewPageChangeListenerHelper(SnapHelper snapHelper, OnPageChangeListener onPageChangeListener) {
    this.snapHelper = snapHelper;
    this.onPageChangeListener = onPageChangeListener;
  }

  @Override
  public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    super.onScrolled(recyclerView, dx, dy);
    if (onPageChangeListener != null) {
      onPageChangeListener.onScrolled(recyclerView, dx, dy);
    }
  }

  @Override
  public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
    super.onScrollStateChanged(recyclerView, newState);
    int position = 0;
    RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    //获取当前选中的itemView
    View view = snapHelper.findSnapView(layoutManager);
    if (view != null) {
      //获取itemView的position
      position = layoutManager.getPosition(view);
    }
    if (onPageChangeListener != null) {
      onPageChangeListener.onScrollStateChanged(recyclerView, newState);
      //newState == RecyclerView.SCROLL_STATE_IDLE 当滚动停止时触发防止在滚动过程中不停触发
      if (newState == RecyclerView.SCROLL_STATE_IDLE && oldPosition != position) {
        oldPosition = position;
        onPageChangeListener.onPageSelected(position);
      }
    }
  }

  public interface OnPageChangeListener {
    void onScrollStateChanged(RecyclerView recyclerView, int newState);

    void onScrolled(RecyclerView recyclerView, int dx, int dy);

    void onPageSelected(int position);
  }
}

View view = forbitLayoutManager.findViewByPosition(position);
  //有时会获取到null,是因为页面还没有渲染完成，可以使用
  recyclerView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver
        .OnGlobalLayoutListener() {
      @Override
      public void onGlobalLayout() {
       //会多次调用，执行完逻辑之后取消监听
          recyclerView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
      }
    });

 private void convertCWACT(CW cw, int seconds,boolean isSeek) {
    List<CWACT> cwacts = cw.getACT();
    //如何是播放器跳转，先回到首页，清空所有item中的画板，防止从高时间跳转到低时间出现错误
    if(isSeek){
      position =0;
      forbitLayoutManager.scrollToPosition(position);
      forbitLayoutManager.setStackFromEnd(true);
      for(int i=0;i<recyclerViewList.size();i++){
        View view = recyclerViewList.get(i);
        if(view!=null){
          SimpleDoodleView doodleView = view.findViewById(R.id.doodleView);
          doodleView.clear();
        }
      }
    }
    for (CWACT cwact : cwacts) {
      int time = cwact.getTime();
      if(isSeek?time > seconds:time != seconds){
        continue;
      }
      if ("switch".equals(cwact.getAction())) {//切换页面
        position = cwact.getCwSwitch().getIndex();
        forbitLayoutManager.scrollToPosition(position);
        forbitLayoutManager.setStackFromEnd(true);
      } else if ("line".equals(cwact.getAction())) {//划线
        if(position>recyclerViewList.size()-1){
          continue;
        }
        View view = recyclerViewList.get(position);
        if(view!=null){
          SimpleDoodleView doodleView = view.findViewById(R.id.doodleView);
          doodleView.setDrawPath(cwact.getLine());
        }
      } else if ("clear".equals(cwact.getAction())) {//清屏
        if(position>recyclerViewList.size()-1){
          continue;
        }
        View view = recyclerViewList.get(position);
        if(view!=null){
          SimpleDoodleView doodleView = view.findViewById(R.id.doodleView);
          doodleView.clear();
        }
      }
    }
  }