[英]How can I use For loops to reduce the number of lines in the following code?
我试图用SQLite中的数据填充列表。如何使用For循环来减少以下代码中的行数? 我将不得不将String Arrays fa,fe,fi,fo传递给ListAdapter。
arrayList = new ArrayList<>();
Cursor res = myhelp.getAllData();
if (res.getCount() == 0) {
Toast.makeText(this, "No data", Toast.LENGTH_SHORT).show();
}else {
while (res.moveToNext()) {
arrayList.add(res.getString(0));
fa = arrayList.toArray(new String[0]);
}
}
arrayList1 = new ArrayList<>();
Cursor res1 = myhelp.getAllData();
while (res1.moveToNext()) {
arrayList1.add(res1.getString(1));
fe = arrayList1.toArray(new String[0]);
}
arrayList2 = new ArrayList<>();
Cursor res2 = myhelp.getAllData();
while (res2.moveToNext()) {
arrayList2.add(res2.getString(2));
fi = arrayList2.toArray(new String[0]);
}
arrayList3 = new ArrayList<>();
Cursor res3 = myhelp.getAllData();
while (res3.moveToNext()) {
arrayList3.add(res3.getString(3));
fo = arrayList3.toArray(new String[0]);
}
由于您的源数据始终相同,因此您无需多次重新读取它,并且可以循环一次
arrayList = new ArrayList<>();
arrayList1 = new ArrayList<>();
arrayList2 = new ArrayList<>();
// etc
Cursor res = myhelp.getAllData();
while (res.moveToNext()) {
arrayList.add(res.getString(0));
fa = arrayList.toArray(new String[0]);
arrayList1.add(res.getString(1));
fe = arrayList1.toArray(new String[0]);
arrayList2.add(res.getString(2));
fi = arrayList2.toArray(new String[0]);
// etc
}
注意
不确定fa = arrayList.toArray(new String[0]);
正在做但我认为你可以在循环后做到这一点
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