如何切换 ListView 项目颜色并保存？

Question

我正在开发一个考勤应用程序。该应用程序有ListActivity 由学生列表组成。我想将颜色更改为红色和绿色，表示不存在和存在。问题是如果我的学生名单比屏幕长。当前视图向下或向上的项目会失去颜色。我的方法正确吗？如何保存每个单独列表项的颜色。当然，如果除了使用ListView 之外还有其他最佳方法，我愿意接受建议。

这是包含列表的 ListActivity

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boolean colorRed 来检查颜色，因为我无法将视图颜色与colors xml 的颜色进行比较。

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;
            }
        }
    });

ListView 的CustomAdapter 类

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;
}
}

我已经仔细检查了这是一个独特的问题！放心……

提前致谢

Answer 1

创建监听器接口：

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

这是模型类：

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;
    }
}

创建适配器类：

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;
    }
}

现在 MainActivity 类：

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();
    }
}