长时间单击可从适配器检查列表视图项 [英] Check a list view item from adapter when long clicked
本文介绍了长时间单击可从适配器检查列表视图项的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我为适配器设置的笔记应用程序设置了listview.列表视图组件由一些textviews和一个复选框组成，当长按listview项时，该复选框会弹出删除图标.
当删除图标变为可见时，我会自动从适配器中显示checkboxes，以便用户可以选择他要删除的项目.
I have a listview for a note application set with my adapter. The list view component consists of some textviewsand a checkbox which pops up delete icon when a listviewitem is long clicked.
Am automatically making the checkboxes visible from the adapter when the delete icon becomes visible so that the user could select the items he wants to delete.
问题是我希望长按鼠标一次即可自动检查单个列表项.我该怎么办?我的逻辑不起作用.
The problem is i want a single list item to be automatically checked when long clicked. How do i go about this? My logic does not work.
listcomponent.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_marginTop="6dp"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
android:background="#F5F5F5"
android:layout_width="match_parent"
android:layout_height="match_parent">
<View
android:id="@+id/verticallineview"
android:layout_width="4dp"
android:layout_height="match_parent"
android:background="@color/toast_color"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="1"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
<TextView
android:id="@+id/list_note_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:padding="1dp"
android:textStyle="bold"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="@color/light_black" />
<TextView
android:id="@+id/list_note_date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="1dp"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textColor="@color/colorPrimary"
android:text=""
/>
<TextView
android:id="@+id/list_note_content_preview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="1dp"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text=""
android:textColor="@color/light_black"
/>
</LinearLayout>
<CheckBox
android:id="@+id/checkbox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:layout_marginEnd="5dp"
android:theme="@style/checkBoxStyle"
android:visibility="gone"
android:gravity="center"
android:layout_gravity="center"
android:layout_marginRight="5dp" />
</LinearLayout>
</LinearLayout>
适配器
class NoteListAdapter extends ArrayAdapter<Note>{
private List<Note> objects;
private List<Note> originalList = new ArrayList<>();
boolean isLongPressed;
// boolean isChecked;
boolean[] isChecked;
private boolean isItemsChecked;
NoteListAdapter(Context context, int resource, List<Note> objects) {
super(context, resource, objects);
this.objects = objects;
this.originalList.addAll(objects);
isLongPressed = false;
// isChecked = false;
isChecked = new boolean[objects.size()];
for(int i=0; i<isChecked.length; i++) isChecked[i] = false;
}
@Override
public int getCount() {
return objects.size();
}
@Nullable
@Override
public Note getItem(int position) {
return objects.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_component, parent, false);
}
Note note = getItem(position);
if (note != null) {
TextView title = convertView.findViewById(R.id.list_note_title);
TextView content = convertView.findViewById(R.id.list_note_content_preview);
TextView date = convertView.findViewById(R.id.list_note_date);
// setting checkbox logic on the adapter
CheckBox checkBox = convertView.findViewById(R.id.checkbox);
// now i wanna toggle checked items from a checkbox on my header
if (isItemsChecked) {
checkBox.setChecked(true);
} else {
checkBox.setChecked(false);
}
if (isLongPressed) {
checkBox.setVisibility(View.VISIBLE);
} else {
checkBox.setVisibility(View.GONE);
}
// also handle checks for all list view items
checkBox.setChecked(isChecked[position]);
checkBox.setTag(position);
checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
CheckBox cb = (CheckBox) v;
int checkedPosition = (int)cb.getTag();
isChecked[checkedPosition] = cb.isChecked();
notifyDataSetChanged();
}
});
}
return convertView;
}
void showCheckbox(int clickedPosition) {
isLongPressed = true;
for(int i=0; i<isChecked.length; i++) isChecked[i] = false;
isChecked[clickedPosition] = true;
notifyDataSetChanged(); // Required for update
}
void removeCheckbox() {
isLongPressed = false;
notifyDataSetChanged(); // Required for update
}
void Check() {
isItemsChecked = true;
notifyDataSetChanged(); // Required for update
}
void Uncheck() {
isItemsChecked = false;
notifyDataSetChanged(); // Required for update
}
NoteActivity.java
private void listViewLongClick() {
mListNotes.setLongClickable(true);
mListNotes.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
// universal button controls all checked items
Checkbox universalCheckBox = findViewById(R.id.check_all);
universalCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked){
na.Check();
} else {
na.Uncheck();
}
}
});
mDeleteButton = findViewById(R.id.delete_icon);
na.showCheckbox();
deleteButtonIn();
return true;
}
});
}
推荐答案
尝试以下代码:
适配器:
class NoteListAdapter extends ArrayAdapter<Note>{
private List<Note> objects;
private List<Note> originalList = new ArrayList<>();
boolean isLongPressed;
// boolean isChecked;
boolean[] isChecked;
NoteListAdapter(Context context, int resource, List<Note> objects) {
super(context, resource, objects);
this.objects = objects;
this.originalList.addAll(objects);
isLongPressed = false;
// isChecked = false;
isChecked = new boolean[objects.size()];
for(int i=0; i<isChecked.length; i++) isChecked[i] = false;
}
@Override
public int getCount() {
return objects.size();
}
@Nullable
@Override
public Note getItem(int position) {
return objects.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_component, parent, false);
}
Note note = getItem(position);
if (note != null) {
TextView title = convertView.findViewById(R.id.list_note_title);
TextView content = convertView.findViewById(R.id.list_note_content_preview);
TextView date = convertView.findViewById(R.id.list_note_date);
// setting checkbox logic on the adapter
CheckBox checkBox = convertView.findViewById(R.id.checkbox);
// now i wanna toggle checked items from a checkbox on my header
// if (isItemsChecked) {
// checkBox.setChecked(true);
// } else {
// checkBox.setChecked(false);
// }
if (isLongPressed) {
checkBox.setVisibility(View.VISIBLE);
} else {
checkBox.setVisibility(View.GONE);
}
// also handle checks for all list view items
checkBox.setChecked(isChecked[position]);
checkBox.setTag(position);
checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
CheckBox cb = (CheckBox) v;
int checkedPosition = (int)cb.getTag();
isChecked[checkedPosition] = cb.isChecked();
notifyDataSetChanged();
}
});
}
return convertView;
}
void showCheckbox(int clickedPosition) {
isLongPressed = true;
for(int i=0; i<isChecked.length; i++) isChecked[i] = false;
isChecked[clickedPosition] = true;
notifyDataSetChanged(); // Required for update
}
void removeCheckbox() {
isLongPressed = false;
notifyDataSetChanged(); // Required for update
}
void checkboxAllChange(boolean state) {
isLongPressed = true;
for(int i=0; i<isChecked.length; i++) isChecked[i] = state;
notifyDataSetChanged(); // Required for update
}
// void Check() {
// isChecked = true;
// notifyDataSetChanged(); // Required for update
// }
// void Uncheck() {
// isChecked = false;
// notifyDataSetChanged(); // Required for update
// }
}
活动中:
mListNotes.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
deleteButtonIn();
na.showCheckBox(position);
return true;
}
});
Checkbox universalCheckBox = findViewById(R.id.check_all);
universalCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
na.checkboxAllChange(buttonView.isChecked());
}
});
这篇关于长时间单击可从适配器检查列表视图项的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
