jamendo之主界面分析(1)【列表部分】

来源：互联网发布：网络上cp是什么意思编辑：程序博客网时间：2024/04/30 05:30

主要的对象有：

PurpleEntry(这个类是定义每行列表的属性)，

//首页上列表的图片资源
private Integer mDrawable;
//显示的标题
private String mText;
//显示标题的资源ID
private Integer mTextId;
//监听器
private PurpleListener mListener;

ArrayListAdapter(继承自BaseAdapter)里面定义了一个ArrayList类型的list来存放数据，

PurpleAdapter(这个类是继承自ArrayListAdapter)用来匹配视图，

SeparatedListAdapter(这个类是用来存放各个purpleAdapter，并绑定界面的adapter，继承自BaseAdapter)，

下面分析详细过程：

代码中先new出了两个ArrayListAdapter对象来存放不同分组的PurpleEntry(其实就是列表的两个组，BrowseJamendo和MyLibrary)，

mBrowseJamendoPurpleAdapter = new PurpleAdapter(this);
mMyLibraryPurpleAdapter = new PurpleAdapter(this);

然后他用两个ArrayList对象来放入各个Purple对象，（每一个ArrayList对象对应一个PurpleAdapter对象）
ArrayList<PurpleEntry> browseListEntry = new ArrayList<PurpleEntry>();
  ArrayList<PurpleEntry> libraryListEntry = new ArrayList<PurpleEntry>();
browseListEntry.add(new PurpleEntry(R.drawable.list_search, R.string.search, new PurpleListener(){
   @Override
   public void performAction() {
    // TODO Auto-generated method stub
    Toast.makeText(MainActivity.this, "启动Search模块", Toast.LENGTH_LONG).show();
    //SearchActivity.launch(MainActivity.this);
   }
  }));
  browseListEntry.add(new PurpleEntry(R.drawable.list_radio,R.string.radio,new PurpleListener(){
   @Override
   public void performAction() {
    // TODO Auto-generated method stub
    Toast.makeText(MainActivity.this, "启动Radio模块", Toast.LENGTH_LONG).show();
   }
  }));
  browseListEntry.add(new PurpleEntry(R.drawable.list_top,R.string.most_listened,new PurpleListener(){
   @Override
   public void performAction() {
    // TODO Auto-generated method stub
    Toast.makeText(MainActivity.this, "启动Most-Listened模块", Toast.LENGTH_LONG).show();
   }
  }));
  libraryListEntry.add(new PurpleEntry(R.drawable.list_playlist, R.string.playlists, new PurpleListener(){
   @Override
   public void performAction() {
    // TODO Auto-generated method stub
    Toast.makeText(MainActivity.this, "启动PlayList模块", Toast.LENGTH_LONG).show();
   }
  }));
  if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
   libraryListEntry.add(new PurpleEntry(R.drawable.list_download,R.string.download, new PurpleListener(){
    @Override
    public void performAction() {
     // TODO Auto-generated method stub
     Toast.makeText(MainActivity.this, "启动downLoad模块", Toast.LENGTH_LONG).show();
    }
   }));
  }
adapter和Arraylist对象一一对应
mBrowseJamendoPurpleAdapter.setMlist(browseListEntry);
mMyLibraryPurpleAdapter.setMlist(libraryListEntry);

把各个PurpleAdapter存放至SeparatedListAdapter对象中：
SeparatedListAdapter separatedAdapter = new SeparatedListAdapter(this);
separatedAdapter.addSection(getString(R.string.browse_jamendo), mBrowseJamendoPurpleAdapter);
separatedAdapter.addSection(getString(R.string.my_library), mMyLibraryPurpleAdapter);

那么这里PurpleAdapter具体是怎么操作的呢？
在PurpleAdapter里面有两个变量：
private Map<String,Adapter> sections = new LinkedHashMap<String,Adapter>();
public final ArrayAdapter<String> headers;
headers：用来存放分组的标题(也就是BrowseJamendo和MyLibrary），
sections：用来存放各个组对应下的adapter对象。
在getview的时候当position等于0的时候就得到标题的视图，然后就得到改标题下的每一行视图。
(当第一的标题BrowseJamendo，position=0，执行的是标题视图，size在第一的标题的时候始终是4，当position=4的时候，
就会执行 position -= size;sectionnum++;把position变成0，sectionnum加1，然后进行下一个标题。
for(Object section : this.sections.keySet()) {
   Adapter adapter = sections.get(section);
   int size = adapter.getCount() + 1;
   // check if position inside this section
   if(position == 0) return headers.getView(sectionnum, convertView, parent);
   if(position < size) return adapter.getView(position - 1, convertView, parent);
   // otherwise jump into next section
   position -= size;
   sectionnum++;
  }

绑定dapter和监听器
mHomeListView.setAdapter(separatedAdapter);
mHomeListView.setOnItemClickListener(mHomeItemClickListener);

监听器：
private OnItemClickListener mHomeItemClickListener = new OnItemClickListener(){
  @Override
  public void onItemClick(AdapterView<?> adapterView, View view, int index,
    long time) {
//相应个歌监听器事件
PurpleListener listener = ((PurpleEntry)adapterView.getAdapter().getItem(index)).getmListener();
   if(listener != null){
    listener.performAction();
   }
  }
};

至此列表部分分析完成。