[英]How do I get String values on listview from the ArrayList<String[]>?
[英]Extract String from ArrayList which get the item from listview
我想从String的arraylist中提取字符串,该arraylist由listView中的选定项填充。
数组列表的结果是:
{studentName=XXX,studentID=SF10001}
{studentName=YYYY,studentID=SF10002}
我只想获取SF10001和SF10002的studentID。 下面是我的代码:
SparseBooleanArray checked = list.getCheckedItemPositions();
ArrayList<String> selectedItems = new ArrayList<String>();
for (int i = 0; i < checked.size(); i++) {
// Item position in adapter
int position = checked.keyAt(i);
// Add sport if it is checked i.e.) == TRUE!
if (checked.valueAt(i))
selectedItems.add(adapter.getItem(position));
}
String[] outputStrArr = new String[selectedItems.size()];
for (int i = 0; i < selectedItems.size(); i++) {
outputStrArr[i] = selectedItems.get(i);
}
Intent intent = new Intent(getApplicationContext(),
ResultActivity.class);
// Create a bundle object
Bundle b = new Bundle();
b.putStringArray("selectedItems", outputStrArr);
// Add the bundle to the intent.
intent.putExtras(b);
// start the ResultActivity
startActivity(intent);
}
这就是结果Activity.java
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_result);
Bundle b = getIntent().getExtras();
String[] resultArr = b.getStringArray("selectedItems");
ListView lv = (ListView) findViewById(R.id.outputList);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, resultArr);
lv.setAdapter(adapter);
}
@SoulRayder因此,我创建了一个StudentData类:
public class StudentData implements Serializable {
String studentName;
String studentID;
public String getStudentNameStudentData() {
return studentName;
}
public String getStudentID()
{
return studentID;
}
我像tis一样更改代码:
SparseBooleanArray checked = list.getCheckedItemPositions();
ArrayList<StudentData> selectedItems = new ArrayList<StudentData>();
for (int i = 0; i < checked.size(); i++) {
// Item position in adapter
int position = checked.keyAt(i);
// Add sport if it is checked i.e.) == TRUE!
if (checked.valueAt(i))
selectedItems.add(adapter.getItem(position));
}
String[] outputStrArr = new String[selectedItems.size()];
for (int i = 0; i < selectedItems.size(); i++) {
outputStrArr[i] = selectedItems.get(i).getStudentID();
}
Intent intent = new Intent(getApplicationContext(),
ResultActivity.class);
// Create a bundle object
Bundle b = new Bundle();
b.putStringArray("selectedItems", outputStrArr);
// Add the bundle to the intent.
intent.putExtras(b);
// start the ResultActivity
startActivity(intent);
}
但是这段代码显示了错误:
selectedItems.add(adapter.getItem(position));
ArrayList不能应用于(java.lang.String)。 如何解决问题。 顺便说一句,谢谢您的立即答复:D
解决问题的两种方法:
1) 更简单的方法,但是效率不高 :(如果可以保证所有字符串都使用确切的模板,或者在下面的函数中添加进一步的验证,则可以使用此方法)
public string extractStudentID(string input)
{
string [] parts = input.substring(1,input.length-1).split(",");
return parts[1].split("=")[1];
}
并在您的代码中使用它,如下所示
for (int i = 0; i < checked.size(); i++) {
// Item position in adapter
int position = checked.keyAt(i);
// Add sport if it is checked i.e.) == TRUE!
if (checked.valueAt(i))
selectedItems.add(extractStudentID(adapter.getItem(position)));
}
2)为您的学生数据创建一个班级
class StudentData
{
public string studentName;
public string studentID;
}
使用这些对象的数组列表,而不是字符串数组列表,并相应地在所有其他位置修改代码:
ArrayList<StudentData> selectedItems = new ArrayList<StudentData>();
然后,您可以随时通过以下方式轻松访问学生证
selectedItems.get(index).studentID;
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