Question

嗨我有String []数组，包含重复数据。我想将这个数组重写为新的String [] array2，没有重复。

Cursor c;
    c= myDbHelper.getReadableDatabase().rawQuery("SELECT * FROM BusPlan", null);

    c.moveToFirst();
    int columnCnt = c.getCount();           
    String[] stringArray = new String[columnCnt]; //deklaracja tablicy stringArray
    String[] stringArray2 = new String[columnCnt];

    for(int i = 0; i < columnCnt ; i++){         
        String variable= new String();
        variable=c.getString(c.getColumnIndex("Bushaltestelle"));
        stringArray2[i] = c.getString(c.getColumnIndex("Bushaltestelle")); 
        c.moveToNext();                             
        for (int j=0;j< columnCnt;j++){
            if(!variable.equals(stringArray2[j].toString())){
                stringArray[j]= c.getString(c.getColumnIndex("Bushaltestelle"));
            }
        }

    }

我做错了什么？如何使它工作？

我使用Hashset解决了问题，但我对此并不满意。

Spinner spinner= (Spinner) findViewById(R.id.spinner);
    Cursor c;
    c= myDbHelper.getReadableDatabase().rawQuery("SELECT * FROM BusPlan", null);
    c.moveToFirst();
    int columnCnt = c.getCount();
    String[] stringArray = new String[columnCnt]; //deklaracja tablicy stringArray
    String[] stringArray2 = new String[columnCnt];
    for(int i = 0; i < columnCnt ; i++){
        stringArray[i] = c.getString(c.getColumnIndex("Bushaltestelle"));
        c.moveToNext();}
    stringArray2 = new HashSet<String>(Arrays.asList(stringArray)).toArray(new String[0]);
    ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(Bodo.this, android.R.layout.simple_spinner_item,stringArray2); //selected item will look like a spinner set from XML
    spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(spinnerArrayAdapter);
    TextView tv = (TextView) findViewById(R.id.textView);
    tv.setText(stringArray[16]);

如果有人知道如何使用数组工作，我会很高兴收到信息

Answer 1

在你的for（int j循环中，你覆盖所有不等于新数据的数据。试试这个：

Cursor c;
c= myDbHelper.getReadableDatabase().rawQuery("SELECT * FROM BusPlan", null);

c.moveToFirst();
int columnCnt = c.getCount();           
String[] stringArray = new String[columnCnt]; //deklaracja tablicy stringArray
String[] stringArray2 = new String[columnCnt];

for(int i = 0; i < columnCnt ; i++){         
    String variable = c.getString(c.getColumnIndex("Bushaltestelle"));
    stringArray[i] = variable; 
    c.moveToNext();
    if (variable == null)
        continue;
    for (int j=0;j< columnCnt;j++){
        if (stringArray2[j] != null && variable.equals(stringArray2[j].toString())) {
            break; // duplicate so ignore
        }
        if (stringArray2[j] == null) {
            stringArray2[j]= variable; // new empty slot, all already added data has already been passed by the loop
            break;
        }
    }

}

为什么我想要重写String []并重复到String []而没有重复时会出现错误

1 个答案: