防止将重复项添加到自定义适配器和数据库

Question

我一直在寻找解决方案，但只是遇到了 HashSet，但我无法实现它。大多数解释都含糊不清，使我很难理解它并用我的例子来实现它。我想使用 HashSet 或同等有效的解决方案。我没有使用过 HashSet，所以如果有人可以解释如何用我的代码实现并解释它是如何工作的或其他解决方案。如果您需要更多代码或不理解我的问题，我会更新我的答案。

适配器

public class LogSearchAdapter extends ArrayAdapter<LogSearch> {
    private static LogSearchAdapter instance;
    Context mContext;
    public static List<LogSearch> mLogs;

    public LogSearchAdapter(Context context, int textViewResourceId, List<LogSearch> logs) {
        super(context, textViewResourceId);
        mContext = context;
        mLogs = logs;
    }

    public void setLogs(List<LogSearch> logs) {
        mLogs = logs;
    }

    public List<LogSearch> getLogs() {
        return mLogs;
    }

    public void add(LogSearch log) {
        mLogs.add(log);
    }

    public void remove(LogSearch log) {
        LogSearchAdapter.mLogs.remove(log);
    }

    public static LogSearchAdapter getInstance(Context mContext) {
        if (instance == null) {
            instance = new LogSearchAdapter(mContext.getApplicationContext(), 4, mLogs);
        }
        return instance;
    }

    public int getCount() {
        return mLogs.size();
    }

    public LogSearch getItem(int position) {
        return mLogs.get(position);
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        LogSearchRow view = (LogSearchRow) convertView;
        if (view == null) {
            view = new LogSearchRow(mContext);
        }
        LogSearch log = getItem(position);
        view.setLog(log);
        return view;
    }
}

活动

etSearch = (EditText) findViewById(R.id.etSearch);
listSearch = (ListView) findViewById(R.id.listSearch);
logSearchAdapter = new LogSearchAdapter(this, 0, LogSearch.all());
listSearch.setAdapter(logSearchAdapter);


etSearch.setOnEditorActionListener(new TextView.OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        if (actionId == EditorInfo.IME_ACTION_SEARCH) {
            search();
            // Saving items to the Database
            LogSearch LogSearch = new LogSearch();
            LogSearch.setName(etSearch.getText().toString());
            LogSearch.save();
            // Adding the saved item to the Adapter
            logSearchAdapter.add(LogSearch);
            logSearchAdapter.notifyDataSetChanged();
            //  listSearch.setVisibility(View.GONE);
            return true;
        }
        return false;
    }
});

工作解决方案感谢 Pramod Yadav

etSearch = (EditText) findViewById(R.id.etSearch);
listSearch = (ListView) findViewById(R.id.listSearch);
Set<String> set=new HashSet<String>();
logSearchAdapter = new LogSearchAdapter(this, 0, LogSearch.all());
listSearch.setAdapter(logSearchAdapter);


etSearch.setOnEditorActionListener(new TextView.OnEditorActionListener() {
    @Override
    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
        if (actionId == EditorInfo.IME_ACTION_SEARCH) {
            // search();
            // Adding the names from the adapter to to the Set
            for (int i = 0; i < logSearchAdapter.getCount(); i++) {
                LogSearch ls = logSearchAdapter.getItem(i);
                set.add(ls.getName());
            }
            if (set.add(etSearch.getText().toString())) {
                // Saving items to the Database
                LogSearch LogSearch = new LogSearch();
                LogSearch.setName(etSearch.getText().toString());
                LogSearch.save();
                // Adding the saved item to the Adapter
                logSearchAdapter.add(LogSearch);
                logSearchAdapter.notifyDataSetChanged();
            } else {
                //do whatever you want to do for duplicate values
            }
            // listSearch.setVisibility(View.GONE);
            return true;
        }
        return false;
    }
});

Answer 1

您可以做的是创建一个哈希图并跟踪没有重复值

etSearch = (EditText) findViewById(R.id.etSearch);
listSearch = (ListView) findViewById(R.id.listSearch);
Set<String> set=new HashSet<String>();
logSearchAdapter = new LogSearchAdapter(this, 0, LogSearch.all());
listSearch.setAdapter(logSearchAdapter);


etSearch.setOnEditorActionListener(new TextView.OnEditorActionListener() {
@Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
    if (actionId == EditorInfo.IME_ACTION_SEARCH) {
        search();
        // Saving items to the Database
        if(set.add(etSearch.getText().toString()))
       {
        LogSearch LogSearch = new LogSearch();
        LogSearch.setName(etSearch.getText().toString());
        LogSearch.save();
        // Adding the saved item to the Adapter
        logSearchAdapter.add(LogSearch);
        logSearchAdapter.notifyDataSetChanged();
     }
      else
       {
           //do whatever you want to do for duplicate values
         }
        //  listSearch.setVisibility(View.GONE);
        return true;
    }
    return false;
}
 });

因为您将永远将值存储在哈希集中，就好像哈希集不包含该值一样，那么 set.add() 方法将返回 true，并且该值将被添加到哈希集中，并且如果该值已经存在于哈希集中然后它会返回false，希望它能澄清事情