[英]Custom List Fragment list item increases every time when i press back button
在我的自定義列表片段中,我正在顯示糖果名稱及其圖像的列表(甜味A,甜味B,甜味C)。 請檢查我的Sweet.java代碼。 當用戶單擊列表項時,它將在“片段”中顯示相應的糖果。 這個概念運行良好。 但是我的問題是,當用戶在查看相應的甜品之后單擊后退按鈕時,列表項顯示兩次。 (即甜A,甜B,甜C,甜A,甜B,甜C)。 (僅前3個項目可點擊)。 再一次,如果我單擊列表項(即甜A),它將轉到甜A。如果我單擊“后退”按鈕,則列表將自身再克隆一次。 它顯示為(甜味A,甜味B,甜味C,甜味A,甜味B,甜味C,甜味A,甜味B,甜味C)。 請幫我。
這是我的Sweet.java代碼
public class Sweet extends ListFragment {
String[] players = {"sweet A", "sweet B", "sweet C"};
int[] images = {R.drawable.veg, R.drawable.veg2, R.drawable.veg};
ArrayList<HashMap<String, String>> data = new ArrayList<HashMap<String, String>>();
SimpleAdapter adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
HashMap<String, String> map = new HashMap<String, String>();
for (int i = 0; i < players.length; i++) {
map = new HashMap<String, String>();
map.put("Player", players[i]);
map.put("Image", Integer.toString(images[i]));
data.add(map);
}
String[] from = {"Player", "Image"};
int[] to = {R.id.nameTxt, R.id.imageView1};
adapter = new SimpleAdapter(getActivity(), data, R.layout.sweet, from, to);
setListAdapter(adapter);
return super.onCreateView(inflater, container, savedInstanceState);
}
@Override
public void onStart() {
super.onStart();
getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> av, View v, int pos,
long id) {
selectItem(pos);
}
});
}
private void selectItem(int pos) {
Fragment newFragment;
FragmentTransaction transaction = getFragmentManager().beginTransaction();
switch (pos) {
case 0:
newFragment = new SweetA();
transaction.replace(R.id.containerID, newFragment);
transaction.addToBackStack(null);
transaction.commit();
break;
case 1:
newFragment = new SweetB();
transaction.replace(R.id.containerID, newFragment);
transaction.addToBackStack(null);
transaction.commit();
break;
}
}
@Override
public String toString() {
return "Home";
}
}
這是我的sweet.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:background="@drawable/customshape"
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="20dp"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
android:src="@drawable/veg" />
<TextView
android:id="@+id/nameTxt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/imageView1"
android:layout_marginTop="10dp"
android:padding="10dp"
android:layout_toRightOf="@+id/imageView1"
android:text="Name"
android:textAppearance="?android:attr/textAppearanceMedium" />
</RelativeLayout>
在片段中一次調用onCreate方法,但是在第一次創建該片段時甚至在從后堆棧加載片段時都調用onCreateView(),因此每當您按回時,都會從后堆棧中拾取片段並符合邏輯數據再次添加。 因此,為了糾正這種情況,您可以將列表設為本地,以防止一次又一次地添加數據。
這也可以解決問題。 感謝您的幫助Neha
newFragment = new SweetA();
transaction.addToBackStack(null);
transaction.hide(this);
transaction.add(R.id.containerID, newFragment);
transaction.commit();
break;
完整的代碼如下
public class Sweet extends ListFragment {
String[] players = {"sweet A", "sweet B", "sweet C"};
int[] images = {R.drawable.veg, R.drawable.veg2, R.drawable.veg};
ArrayList<HashMap<String, String>> data = new ArrayList<HashMap<String, String>>();
SimpleAdapter adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
HashMap<String, String> map = new HashMap<String, String>();
for (int i = 0; i < players.length; i++) {
map = new HashMap<String, String>();
map.put("Player", players[i]);
map.put("Image", Integer.toString(images[i]));
data.add(map);
}
String[] from = {"Player", "Image"};
int[] to = {R.id.nameTxt, R.id.imageView1};
adapter = new SimpleAdapter(getActivity(), data, R.layout.sweet, from, to);
setListAdapter(adapter);
return super.onCreateView(inflater, container, savedInstanceState);
}
@Override
public void onStart() {
super.onStart();
getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> av, View v, int pos,
long id) {
selectItem(pos);
}
});
}
private void selectItem(int pos) {
Fragment newFragment;
FragmentTransaction transaction = getFragmentManager().beginTransaction();
switch (pos) {
case 0:
newFragment = new SweetA();
transaction.addToBackStack(null);
transaction.hide(this);
transaction.add(R.id.containerID, newFragment);
transaction.commit();
break;
}
}
@Override
public String toString() {
return "Home";
}
}
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