如何切換ListView項目顏色並保存？

Question

我正在參加考勤應用。該應用程序有ListActivity由學生列表組成。我想改變顏色爲紅色和綠色表示缺席和呈現。問題是如果我有很長的學生名單而不是屏幕。當前視圖中向下或向上的項目會丟失顏色。我的方法是否正確？如何保存每個單獨列表項目的顏色。當然，如果除了使用ListView之外還有其他最好的方法，我願意接受建議。

下面是一個包含列表

public class ListActivity extends Activity implements Serializable{ 
private String userName; 
private TextView nameTextView; 
private ListView nameList; 
private CustomAdapter adapter; 
private boolean colorRed; 
private Class myClass; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_list); 

    myClass = new Class(); 
    colorRed = false; 
//   Open the students list from file if exists 
    openFromFile(); 

    nameList = (ListView) findViewById(R.id.nameListView); 
    nameTextView = (TextView) findViewById(R.id.nameTextView); 
    Bundle extras = getIntent().getExtras(); 
    if (extras != null) { 
     userName = extras.getString("NAME"); 
     nameTextView.setText("Hi! " + userName); 
    } 

    adapter = new CustomAdapter(this, myClass.getStudentNames()); 
    nameList.setAdapter(adapter); 
    TextView tv = (TextView) findViewById(R.id.sNametv); 
    nameList.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) { 

      if (colorRed == true) { 
       view.setBackgroundColor(ContextCompat.getColor(getBaseContext(), R.color.colorPresent)); 
       colorRed = false; 
      } else { 
       view.setBackgroundColor(ContextCompat.getColor(getBaseContext(), R.color.colorAbsent)); 
       colorRed = true; 
      } 

//    ALso could use this 
//    adapterView.getChildAt(position).setBackgroundColor(Color.RED); 

     } 
    }); 
} 

我使用的是boolean colorRed檢查顏色，我無法看到的顏色與顏色從colors xml比較ListActivity。

nameList.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) { 
      if (colorRed == true) { 
       view.setBackgroundColor(ContextCompat.getColor(getBaseContext(), R.color.colorPresent)); 
       colorRed = false; 
      } else { 
        view.setBackgroundColor(ContextCompat.getColor(getBaseContext(), R.color.colorAbsent)); 
       colorRed = true; 
      } 
     } 
    }); 

CustomAdapter班的ListView

public class CustomAdapter extends ArrayAdapter<String> { 

public CustomAdapter(Context context, ArrayList<String> names) { 
    super(context, R.layout.custom_layout, names); 

} 

@NonNull 
@Override 
public View getView(int position, View convertView, ViewGroup parent) { 

    LayoutInflater inflater = LayoutInflater.from(getContext()); 
    View customView = inflater.inflate(R.layout.custom_layout, parent, false); 
    String singleName = getItem(position); 
    TextView tv = (TextView) customView.findViewById(R.id.sNametv); 
    tv.setText(singleName); 

    return customView; 
} 
} 

我仔細檢查過這是一個獨特的問題！放心......

預先感謝您

Answer 1

創建監聽器接口：

public interface ListListener { 
    void clickListItem(int position); 
} 

這裏是模型類：

public class Route { 
    String studentName; 
    boolean colorRed; 

    public Route(String studentName, boolean colorRed) { 
     this.studentName=studentName; 
     this.colorRed=colorRed; 
    } 

    public String getStudentName() { 
     return studentName; 
    } 

    public void setStudentName(String studentName) { 
     this.studentName = studentName; 
    } 

    public boolean isColorRed() { 
     return colorRed; 
    } 

    public void setColorRed(boolean colorRed) { 
     this.colorRed = colorRed; 
    } 
} 

創建適配器類：

public class AAdapter extends BaseAdapter implements View.OnClickListener { 

    Context context; 
    private List<Route> routes; 
    Holder holder; 
    private static LayoutInflater inflater=null; 
    ListListener listListener; 

    public AAdapter(Context context, List<Route> names,ListListener listListener) { 
     this.routes=names; 
     this.context=context; 
     this.listListener=listListener; 
     inflater = (LayoutInflater)context. 
       getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    } 

    @Override 
    public void onClick(View view) { 
     listListener.clickListItem((Integer)view.getTag()); 
    } 

    private class Holder 
    { 
     TextView tv; 
    } 

    @Override 
    public Route getItem(int position) { 
     return routes.get(position); 
    } 

    @Override 
    public long getItemId(int position) { 
     return position; 
    } 

    @Override 
    public int getCount() { 
     return routes.size(); 
    } 

    @NonNull 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 

     if (convertView==null){ 
      holder=new Holder(); 

      convertView=inflater.inflate(R.layout.custom_layout,null); 

      holder.tv=(TextView)convertView.findViewById(R.id.textView); 
      holder.tv.setOnClickListener(this); 
      convertView.setTag(holder); 

     }else { 
      holder=(Holder)convertView.getTag(); 
     } 

     holder.tv.setText(routes.get(position).getStudentName()); 
     holder.tv.setTag(position); 

     if (!routes.get(position).colorRed){ 
      holder.tv.setBackgroundColor(Color.GREEN); 
     }else { 
      holder.tv.setBackgroundColor(Color.RED); 
     } 
     return convertView; 
    } 
} 

現在MainActivity類：

public class MainActivity extends AppCompatActivity implements ListListener{ 

    AAdapter adapter; 
    ListView lv; 
    List<Route> myNames; 
    ListListener listListener=MainActivity.this; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     lv=(ListView)findViewById(R.id.listnames); 


     myNames=new ArrayList<>(); 

     /* DEMO DATA U NEED TO FETCH YOUR DATA */ 
     myNames.add(new Route("FIRST",false)); 
     myNames.add(new Route("Second",false)); 
     myNames.add(new Route("Third",false)); 
     myNames.add(new Route("Fourth",false)); 
     myNames.add(new Route("Fifth",false)); 

     myNames.add(new Route("FIRST",false)); 
     myNames.add(new Route("Second",false)); 
     myNames.add(new Route("Third",false)); 
     myNames.add(new Route("Fourth",false)); 
     myNames.add(new Route("Fifth",false)); 

     myNames.add(new Route("FIRST",false)); 
     myNames.add(new Route("Second",false)); 
     myNames.add(new Route("Third",false)); 
     myNames.add(new Route("Fourth",false)); 
     myNames.add(new Route("Fifth",false)); 

     myNames.add(new Route("FIRST",false)); 
     myNames.add(new Route("Second",false)); 
     myNames.add(new Route("Third",false)); 
     myNames.add(new Route("Fourth",false)); 
     myNames.add(new Route("Fifth",false)); 


     adapter = new AAdapter(this, myNames,listListener); 
     lv.setAdapter(adapter); 
     adapter.notifyDataSetChanged(); 
    } 

    @Override 
    public void clickListItem(int position) { 
     if(myNames.get(position).colorRed){ 
      myNames.get(position).colorRed=false; 
     }else { 
      myNames.get(position).colorRed=true; 
     } 
     adapter.notifyDataSetChanged(); 
    } 
}