• Android第三次作业


    1.实现功能: 实现点击列表播放音乐,点击按钮播放上一首,下一首及暂停的功能 ;显示播放列表 ;选中歌曲高亮显示

    2.界面截图:

    3.关键代码:

    //获取音乐信息并用hashmap保存
     if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
                ActivityCompat.requestPermissions(MainActivity.this,new String[]{
                        Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
            }
            try {
                Context context = this;
                Cursor cursor = context.getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,  null ,
                        null ,  null , MediaStore.Audio.Media.DEFAULT_SORT_ORDER);
    
                while (cursor.moveToNext()){
                    String musicNmae = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME));
                    String musicPath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA));
                    musicInfo.put(musicNmae,musicPath);
                }
    
            }catch (Exception e){
                Toast.makeText(getApplicationContext(), "获取音乐失败", Toast.LENGTH_SHORT).show();;
            }
    
            Iterator entries = musicInfo.entrySet().iterator();
            while(entries.hasNext()){
                Map.Entry entry = (Map.Entry) entries.next();
                list.add((String)entry.getKey()) ;
            }
    //设置ListView样式并添加监视
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1 , list){
                public View getView(int position, View convertView, ViewGroup parent) {
                    View view = super.getView(position, convertView, parent);
                    TextView text = (TextView) view.findViewById(android.R.id.text1);
                    text.setTextColor(Color.WHITE);
                    return view;
                }
    
            };
            listView = (ListView) findViewById(R.id.list_view);
            listView.setAdapter(adapter);
            listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView parent, View view, int position, long id) {
                    playingMusicPath = (String)musicInfo.get(list.get(position));
                    playingPosition = position;
                    changePlaying(playingPosition);
    
                    try {
                        mediaPlayer.reset();
                        mediaPlayer.setDataSource(playingMusicPath);
                        mediaPlayer.prepare();
                        mediaPlayer.start();
                    } catch (Exception e) {
                    }
                }
    
            });
    //为上一首、暂停、下一首按键添加监视
     play.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (playingMusicPath.isEmpty())
                        Toast.makeText(getApplicationContext(), "请先选择音乐", Toast.LENGTH_SHORT).show();
                    else{
                        if(mediaPlayer.isPlaying()) {
                            mediaPlayer.pause();
                            play.setImageResource(R.drawable.play);
                        } else{
                            mediaPlayer.start();
                            play.setImageResource(R.drawable.pause);
                        }
                    }
                }
            });
    
    
            previous.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if((playingPosition - 1 ) < 0){
                        playingPosition = (list.size() - 1);
                        changePlaying(playingPosition);
                    } else{
                        playingPosition -= 1;
                        changePlaying(playingPosition);
                    }
    
                    play.setImageResource(R.drawable.pause);
                }
            });
    
            next.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(playingPosition  + 1 > (list.size() - 1)){
                        playingPosition = 0;
                        changePlaying(playingPosition);
                    }else{
                        playingPosition += 1;
                        changePlaying(playingPosition);
                    }
    
                    play.setImageResource(R.drawable.pause);
                }
            });

    4.代码链接:https://git.coding.net/XL_1600802098/MusicPlayer.git

    5.APP链接:https://coding.net/s/b83354ac-e185-4a2d-a472-d738e339ae9b

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  • 原文地址:https://www.cnblogs.com/xinglu1600802098/p/10105680.html
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