Question

我正在制作一个音乐播放器，我放置了一个随机播放Button。

case R.id.ib3:
    // long s1=System.nanoTime();
    setSuffle(); // its is a function just ignore this
    Collections.shuffle(index);
    newlist(); // its is a function just ignore this
    listView.setAdapter(new Song_Adapter(this,al_new));

我的歌曲已添加到ArrayList中，我将List传递给我的自定义适配器，并将其设置为ListView。

我想用索引来实现列表的随机播放，这样当我点击混洗列表时，应该根据新索引播放歌曲。

来自评论的

编辑：

public void onItemClick(AdapterView<?> parent, View v, int l, long m) {
    Bundle bundle = new Bundle(); 
    bundle.putInt("id",y); 
    Intent i=new Intent(this,Second.class); i.putExtras(bundle);      
    //startActivity(i); 
    // globle.setSong_id(l);
    startService(i); }

Answer 1

您不必为Adapter设置新的ListView。保留对适配器的引用并在其上调用notifyDataSetChanged();。

//above onCreate, declare:
private MyCustomAdapter adapter;


//set the adapter ONCE, the first time you need it: 
adapter = new Song_Adapter(this,al_new);
listView.setAdapter(adapter);

//call this everytime your dataset has changed:
adapter.notifyDataSetChanged();

随机播放一首歌：

int randomIndex = new Random().nextInt(mySongList.size());

Answer 2

首先需要对ArrayList进行随机播放，然后使用 notifyDataSetChanged（）;

private Song_Adapter songAdapter;

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


    case R.id.ib3:
         shuffleMySongs();
    break;

    }

     private void shuffleMySongs(){

      //to shuffle your arraylist
        Collections.shuffle(yourArrayList);

      songAdapter = new Song_Adapter(this, yourArrayList);
      songAdapter.notifyDataSetChanged();
      listView.setAdapter(songAdapter);

    }

在Listview中为音乐播放器带来麻烦

2 个答案: