如何使用变量查询我的 sqlite 数据库

Question

我想在文本视图中显示我选择的月份。为此，我有一个微调器，当我在微调器中选择一个月时，它应该会找到我在这个特定月份拥有的所有数据。 我不确定如何使用变量过滤查询，或者如何将变量从我的 Start.java 类传递给我的 KilometerSQL.java 类。

由于我没有使用意图转到 Kilometer.java 类，所以我不知道如何传递变量。

这是我的 Start.java 类

@Override
public void onItemSelected(AdapterView<?> parent, View arg1, int arg2,
        long arg3) {
    // TODO Auto-generated method stub
    String month = parent.getSelectedItem().toString(); //This is my month variable

    KilometerSQL spinner = new KilometerSQL(this);
    spinner.open();

    String dataSpinner = KilometerSQL.spinnerData();
    spinner.close();

    logbog.setText(dataSpinner);

}

这是我的 KilometerSQL.java 类

public static String spinnerData() {
    // TODO Auto-generated method stub
    String [] columns = new String []{ KEY_DAY, KEY_MONTH, KEY_YEAR, KEY_KILOMETER, KEY_LOCATIONS};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_MONTH, null, null, null, null);
    String result = "";

    int iDay = c.getColumnIndex(KEY_DAY);
    int iMonth = c.getColumnIndex(KEY_MONTH);
    int iYear = c.getColumnIndex(KEY_YEAR);
    int iKilometer = c.getColumnIndex(KEY_KILOMETER);
    int iLocations = c.getColumnIndex(KEY_LOCATIONS);

    for (c.moveToFirst();!c.isAfterLast();c.moveToNext()){
        result = result + c.getString(iDay) + "-" + c.getString(iMonth) + "-" + c.getString(iYear) + " " + c.getString(iKilometer) + " " + c.getString(iLocations) + "\n";
    }

    return result;
}

我没有任何运气使用其他用户提供的与我类似的答案。

感谢所有帮助。

Answer 1

在您的 Start.java 类中：

Intent i = new Intent(this, KilometerSQL.class);
i.putExtra("KEY",YourData);

在KilometerSQL.java 类中

Bundle extras = getIntent().getExtras();
if(extras !=null) {
    String value = extras.getString("KEY");
}

//Declare ur Textview here and set text to value

编辑 您是否尝试过以上方法，或者您也可以在 start 类中尝试 spinnerData(dataSpinner) 并在 killometerSql 类中更改 String spinnerData(String dataSpinner)

开始上课

public void onItemSelected(AdapterView<?> parent, View arg1, int arg2,
        long arg3) {
    // TODO Auto-generated method stub
    String month = parent.getSelectedItem().toString(); //This is my month variable

    KilometerSQL spinner = new KilometerSQL(this);
    spinner.open();

    String dataSpinner = KilometerSQL.spinnerData();//you said u want to pass from start to killometer ..Whats this line doing though
    spinner.close();

    logbog.setText(dataSpinner);
    spinnerData(month);


}

公里类

 public static String spinnerData(String KEY_MONTH) {
        // TODO Auto-generated method stub
        String [] columns = new String []{ KEY_DAY, KEY_MONTH, KEY_YEAR, KEY_KILOMETER, KEY_LOCATIONS};
        Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_MONTH, null, null, null, null);
        String result = "";

        int iDay = c.getColumnIndex(KEY_DAY);
        int iMonth = c.getColumnIndex(KEY_MONTH);
        int iYear = c.getColumnIndex(KEY_YEAR);
        int iKilometer = c.getColumnIndex(KEY_KILOMETER);
        int iLocations = c.getColumnIndex(KEY_LOCATIONS);

        for (c.moveToFirst();!c.isAfterLast();c.moveToNext()){
            result = result + c.getString(iDay) + "-" + c.getString(iMonth) + "-" + c.getString(iYear) + " " + c.getString(iKilometer) + " " + c.getString(iLocations) + "\n";
        }

        return result;
    }