思路
android实现录屏功能有两种方案，一种是直接使用android自带的MediaProjectionManager实现录屏功能，第二种是是只录语音，用户的操作通过某种方式进行记录保存，最后通过某种协议进行播放。
两种方案各有各的优缺点，前者实现方式简单，但无法只录制特定区域的画面，并且生成的视频文件一般都比较大。后者实现较为繁琐，音频录制android7.0之前没有暂停方法，只能生成多个文件，然后对音频进行合成。用户的操作需要自己进行保存，播放时还原。播放器需要自定义生成。但后者的好处是可扩展性高，支持特定区域录制，并且生成的音频文件比较小。
需求
录制画板，画板要求可以更改颜色粗细，可以擦除。画板底部可以是白板，图片。图片要求是相机拍摄或者本地图片。可以播放录制内容；需要上传，所以文件要小，所有只能选择第二种方式。
 -[-/a>
整个项目生成的是一个文件夹，文件夹中包含一个MP3文件，一个cw协议文件（存储用户的操作），图片。整个画板是一个recyclerView，item中包含一个涂鸦画板，图片控件。播放时读取cw协议文件，按照时间一个个绘制，协议内容包含画板各个页的内容是空白画板还是图片，时间点，操作（切换图片/画线）。
音频
//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();
}
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/**
* 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();
}
}
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音频播放
mediaPlayer = new MediaPlayer();
mediaPlayer.setDataSource(path);
mediaPlayer.prepare();
mediaPlayer.start();
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recyclerView
是否禁止滑动
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();
}
}
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滑动时只滑动一页类似viewPage
mPagerSnapHelper = new PagerSnapHelper();
mPagerSnapHelper.attachToRecyclerView(recyclerView);
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获得当前是第几页，类似viewPage的pageSelect
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);
}
}
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获得当前选择的item（只能获得可视页面item）
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);
}
});
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根据时间进行播放
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();
}
}
}
}
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