java - 通过选择模式在 ListView 中添加条目

Question

我有一个包含电影的 ListView 。该列表在 strings.xml 中声明。用户可以将电影添加到此 ListView ，可以编辑条目并可以删除条目。

我正在实现一种新的“插入”方法，该方法允许用户突出显示(即使用箭头、使用鼠标轨迹球)每个条目，并在所选条目的正下方插入一个新电影。我的问题是，当我从插入 Activity 设置结果时，我的代码中出现 arrayindexoutofbounds 错误:

我的 OnActivityResult 案例之一:

  case INSERT_MOVIE:
            Lab8_082588FetchDetails insertMovie = new Lab8_082588FetchDetails();
            ListView list = getListView();
            list.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
            NumberFormat formatterInsert = new DecimalFormat("###,###,###");

            insertMovie.setTitle(data
                    .getStringExtra(Lab8_082588Insert.TITLE_STRING));
            insertMovie.setGross("$"
                    + formatterInsert.format(Double.parseDouble(data
                            .getStringExtra(Lab8_082588Insert.GROSS_STRING))));
            insertMovie.setDate(data
                    .getStringExtra(Lab8_082588Insert.DATE_STRING));
            results.add(insertMovie);
            adapter.notifyDataSetChanged();

我的OnOptionsItemSelected:

      @Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection using item.getItemId()
    switch (item.getItemId()) {
    case R.id.add:
        add();
        break;
    case R.id.insert:
        insert(item);
        break;
    }
    return true;
}

private void insert(MenuItem item) {
    // TODO Auto-generated method stub
    AdapterContextMenuInfo info = (AdapterContextMenuInfo) item
            .getMenuInfo();
    Intent insertData = new Intent(Lab8_082588.this,
            Lab8_082588Insert.class);
    insertData.putExtra(Lab8_082588.CURRENT_ROW, info.position); //nullPointerException
    startActivityForResult(insertData, Lab8_082588.INSERT_MOVIE);
}

我的插入类:

    public class Lab8_082588Insert extends Activity {

public static final String TITLE_STRING = "TITLE_STRING";
public static final String GROSS_STRING = "GROSS_STRING";
public static final String DATE_STRING = "DATE_STRING";
public static final String PASSED_ROW = "PASSED_ROW";

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.addeditinsert);
    Intent rowNumber = getIntent();
    results.add(data.getIntExtra(Lab8_082588Insert.PASSED_ROW, 0) + 1, insertMovie);
            adapter.notifyDataSetChanged();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu3, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection using item.getItemId()
    switch (item.getItemId()) {
    case R.id.insert2:
        next();
        break;
    }
    return true;
}

private void next() {
    // TODO Auto-generated method stub
    EditText movieTitle = (EditText) findViewById(R.id.etTitle);
    EditText movieGross = (EditText) findViewById(R.id.etGross);
    EditText movieDate = (EditText) findViewById(R.id.etDate);

    String title = movieTitle.getText().toString();
    String gross = movieGross.getText().toString();
    String date = movieDate.getText().toString();

    if ((title.length() > 0) && (gross.length() > 0)
            && (date.length() == 4)) {

        Intent data = getIntent();
        int rowNumber = getIntent().getIntExtra(Lab8_082588.CURRENT_ROW, 0);
        data.putExtra(Lab8_082588Insert.TITLE_STRING, title);
        data.putExtra(Lab8_082588Insert.GROSS_STRING, gross);
        data.putExtra(Lab8_082588Insert.DATE_STRING, date);
        data.putExtra(Lab8_082588Insert.PASSED_ROW, rowNumber);
        setResult(RESULT_OK, data);
        finish();
    }
}

Answer 1

我不完全理解您的代码，但为什么您使用 getCheckedItemPosition() 方法的重新运行作为新插入项目的索引？

如果您只想将它​​们插入到用户选择的行之后，则只需将用户单击的项目的位置传递给insertData，我在您之前的问题中看到您知道如何执行此操作)并将其传递给收集插入数据的 Activity 。在插入 Activity 中，然后沿着用户插入的数据，返回行的位置(将其增加一，以便您可以在下一个位置插入)并将其用作 onActivityResult 中列表添加的索引>.

你没听懂我说的话。在 insert 方法中:

private void insert(MenuItem item) {
    AdapterContextMenuInfo info = (AdapterContextMenuInfo) item
            .getMenuInfo();
    Intent insertData = new Intent(Lab8_082588.this,
            Lab8_082588Insert.class);
    insertData.put("CURRENT_ROW", info.position);// there is no need for extra data, you're going to insert it anyway
    startActivityForResult(insertData, Lab8_082588.INSERT_MOVIE);
}

然后在插入 Activity 中只需获取该行号并在返回结果时将其添加到 Intent 中:

//
super.onCreate(savedInstanceState);
setContentView(R.layout.addeditinsert);
rowNumber = getIntent().getExtra("CURRENT_ROW");

然后将其传递给完成Intent:

    hobby.putExtra(TITLE_STRING, title);
    hobby.putExtra(GROSS_STRING, gross);
    hobby.putExtra(DATE_STRING, date);
    hobby.putExtra("PASSED_ROW", rowNumber);
    setResult(RESULT_OK, hobby);
    finish();

在onActivityResult中:

results.add(data.getIntExtra("PASSED_ROW") + 1, insertMovie);