我有一个溢出菜单，选项之一是“删除列表”。当用户按下它时，我想要它，以便用户添加到屏幕上的所有元素消失/消失。
但是，当我运行代码时，不会发生。第一次按“删除列表”时，它将删除一组元素，然后再次按删除列表，则什么也不会消失。
我的逻辑在这里正确吗？
请参见else if (id == R.id.action_delete)
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
Intent startSettingsActivity = new Intent(this, settings.class);
startActivity(startSettingsActivity);
//start the settings activity here.
return true;
}
else if (id == R.id.action_delete) {
//code to delete list here.
final int listSize = mViews.size();
if (listSize > 0) {
for (int i = 0; i < listSize; i++) {
mCheckboxes.get(listSize - 1).setVisibility(View.GONE);
mSpinners.get(listSize - 1).setVisibility(View.GONE);
mViews.get(listSize - 1).setVisibility(View.GONE);
mTextviews.get(listSize - 1).setVisibility(View.GONE);
mEdittexts.get(listSize - 1).setVisibility(View.GONE);
Toast.makeText(getBaseContext(), "List removed.", Toast.LENGTH_SHORT).show();
}
}
return true;
}
return super.onOptionsItemSelected(item);
}
创建xml
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorBackground"
android:minHeight="170dp"
tools:context=".create"
tools:layout_editor_absoluteY="81dp"
>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/scrollView2"
android:layout_width="match_parent"
android:layout_height="438dp"
android:fillViewport="true"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
tools:layout_editor_absoluteY="0dp">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/my_linearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:id="@+id/verticalLayout"
android:layout_below="@id/view2">
</LinearLayout>
</LinearLayout>
</ScrollView>
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="60dp"
android:layout_height="70dp"
android:layout_gravity="bottom|end"
android:layout_marginBottom="16dp"
android:layout_marginEnd="16dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="16dp"
android:layout_marginStart="8dp"
android:src="@android:drawable/ic_input_add"
app:backgroundTint="@color/colorCreate"
app:elevation="6dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:pressedTranslationZ="12dp"
android:tint="@color/colorBackground"/>
<View
android:id="@+id/subheading"
android:layout_width="match_parent"
android:layout_height="83dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="1dp"
android:layout_marginLeft="1dp"
android:layout_marginRight="1dp"
android:layout_marginStart="1dp"
android:layout_marginTop="2dp"
android:background="@color/colorBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0"
/>
<View
android:id="@+id/view"
android:layout_width="320dp"
android:layout_height="1dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="76dp"
android:background="@color/colorText"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<View
android:id="@+id/view2"
android:layout_width="320dp"
android:layout_height="1dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="28dp"
android:background="@color/colorText"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="12dp"
android:fontFamily="@font/droid_sans"
android:text="@string/done_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/textView4"
app:layout_constraintTop_toBottomOf="@+id/view2" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="128dp"
android:layout_marginRight="128dp"
android:layout_marginTop="8dp"
android:fontFamily="@font/droid_sans"
android:text="@string/aisle_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="@+id/view"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@+id/view2"
app:layout_constraintVertical_bias="1.0" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_marginEnd="32dp"
android:layout_marginRight="32dp"
android:layout_marginTop="5dp"
android:fontFamily="@font/droid_sans"
android:text="@string/qty_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="@+id/view"
app:layout_constraintEnd_toStartOf="@+id/textView4"
app:layout_constraintTop_toBottomOf="@+id/view2"
app:layout_constraintVertical_bias="0.7" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:fontFamily="@font/droid_sans"
android:text="@string/item_label"
android:textColor="@color/colorText"
android:textSize="20sp"
app:layout_constraintBottom_toTopOf="@+id/view"
app:layout_constraintEnd_toStartOf="@+id/textView3"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/view2"
app:layout_constraintVertical_bias="1.0" />
<LinearLayout
android:focusable="true"
android:focusableInTouchMode="true"
android:layout_width="0px"
android:layout_height="0px"/>
</android.support.constraint.ConstraintLayout>
答案 0 :(得分：2)
这很简单
为此LinearLayout分配一个ID（您的View项目的父项，如微调框，代码中的复选框，如代码所示）
然后在您的代码中获取布局
Linearlayout ll = findViewById(R.id.yourLinearlayoutID);
然后您需要在按Delete键时呼叫此行
else if (id == R.id.action_delete) {
//code to delete list here.
ll.setVisibilty(View.GONE); // i am supposed that the for loop you added to remove multiple values if not then add them back
Toast.makeText(getBaseContext(), "List removed.", Toast.LENGTH_SHORT).show();
}
}
return true;
}
希望有帮助
答案 1 :(得分：0)
else if (id == R.id.action_delete) {
for(int j=0; j<mCheckboxes.size(); j++){
mCheckboxes.get(j).setVisibility(View.GONE);
}
for(int j=0; j<mSpinners.size(); j++){
mSpinners.get(j).setVisibility(View.GONE);
}
for(int j=0; j<mViews.size(); j++){
mViews.get(j).setVisibility(View.GONE);
}
for(int j=0; j<mTextviews.size(); j++){
mTextviews.get(j).setVisibility(View.GONE);
}
for(int j=0; j<mEdittexts.size(); j++){
mEdittexts.get(j).setVisibility(View.GONE);
}
Toast.makeText(getBaseContext(), "List removed.", Toast.LENGTH_SHORT).show();
}
it will delete all the view from list. there is no need to calculate mViews.size().