Question

我一直在学习（尝试：-D）Web Audio API。在下面的代码中我想播放 songs [] 数组中的歌曲列表。
但是我收到了错误......请帮助。提前谢谢你。代码： -

var sources = new Array();
var actx;
var songs = ['src1.mp3'];

function start() {
  console.log("WELCOME!!");
  try{
      actx = new AudioContext();
  }catch(e){
    console.log('WebAudio api is not supported!!');

  }
  var buffer_list =getBuffers(actx,songs);
  //console.log("hello");
  //console.log(buffer_list[1]);
  for (var x = 0;x<(buffer_list.length);x++){
    var i = actx.createBufferSource();
    sources[x] = i  ;
  }
  for (var x = 0;x<(buffer_list.length);x++){
    sources[x].buffer = buffer_list[x];

  }
  for(var x = 0;x<(buffer_list.length);x++){
    sources[x].connect(actx.destination);
  }
}

function getBuffers(actx,songs){
  var buffer_list = new Array();
  for (var x = 0;x<songs.length;x++){
    console.log(songs[x]);
      var request = new XMLHttpRequest();
      request.open('GET',songs[x],true);
      request.responseType = 'arraybuffer';
      //onload function for downloading,After sending request.
      request.onload = function(){
        var audioData = request.response;
        //console.log(audioData);
        if(audioData){
          actx.decodeAudioData(audioData,function(buffer){
            //console.log(buffer);
            console.log(x);
            buffer_list[x] = buffer;
          },
          function(e){
            console.log(e.err);
          });
      }else {
        console.error("problem!!");
      }
  }
  request.send();
}
console.log(buffer_list);
return buffer_list;

}

function play() {
  start();
  sources[0].start(0);
  //sources[1].start(0);
}
function stop(){
  sources[0].stop(0);
  //sources[1].stop(0);
}

当我在web控制台中进行调试时，我可以看到数组 buffer_list [] 的音频缓冲区位于 1 而不是0。我随后判断了值 X 。它来了 1 而不是 0 但为什么？我从 0 1 开始 x ？请帮忙.. 为了测试目的，我开始用歌曲[] 中的一首歌开始..

Answer 1

您可以使用adapter.java和public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> { public List<RecyclerItem> listItems; private Context mContext; public MyAdapter(List<RecyclerItem> listItems, Context mContext) { this.listItems = listItems; this.mContext = mContext; } @Override public ViewHolder onCreateViewHolder(final ViewGroup parent, int viewType) { final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item, parent, false); final ViewHolder holder = new ViewHolder(view); view.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { final int position = holder.getAdapterPosition(); // if (position == 0) { Toast.makeText(mContext, listItems.get(position).getTitle(),Toast.LENGTH_SHORT).show(); /* } if (position == 1) { Toast.makeText(mContext,"Android",Toast.LENGTH_SHORT).show(); } */ } }); return holder; } @Override public void onBindViewHolder(final ViewHolder holder, final int position) { final RecyclerItem itemList = listItems.get(position); holder.txtTitle.setText(itemList.getTitle()); holder.txtDescription.setText(itemList.getDescription()); holder.txtOptionDigit.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Display option menu PopupMenu popupMenu = new PopupMenu(mContext, holder.txtOptionDigit); popupMenu.inflate(R.menu.option_menu); popupMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() { @Override public boolean onMenuItemClick(MenuItem item) { switch (item.getItemId()) { case R.id.mnu_item_save: Toast.makeText(mContext, "Saved " + listItems.get(position).getTitle(), Toast.LENGTH_SHORT).show(); break; case R.id.mnu_item_delete: //Delete item Toast.makeText(mContext, "Deleted " + listItems.get(position).getTitle(), Toast.LENGTH_SHORT).show(); listItems.remove(position); notifyDataSetChanged(); break; default: break; } return false; } }); popupMenu.show(); } }); } @Override public int getItemCount() { return listItems.size(); } public class ViewHolder extends RecyclerView.ViewHolder{ public TextView txtTitle; public TextView txtDescription; public TextView txtOptionDigit; public ViewHolder(View itemView) { super(itemView); txtTitle = (TextView) itemView.findViewById(R.id.txtTitle); txtDescription = (TextView) itemView.findViewById(R.id.txtDescription); txtOptionDigit = (TextView) itemView.findViewById(R.id.txtOptionDigit); } } }等待完成多个异步任务

async/await

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1 个答案: