Reputation: 357
Here is my code for measuring height of items inside a listview and setting the list view height based on the total height of it's children.
I do not have any problems when using any other view.
public static void setListViewHeightBasedOnChildren(TwoWayView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
return;
}
int desiredWidth = MeasureSpec.makeMeasureSpec(listView.getWidth(), MeasureSpec.AT_MOST);
int totalHeight = 0;
View listItem = null;
for (int i = 0; i < listAdapter.getCount(); i++) {
listItem = listAdapter.getView(i, listItem, listView);
if (listItem instanceof ViewGroup) {
listItem.setLayoutParams(new ViewGroup.LayoutParams(desiredWidth, ViewGroup.LayoutParams.WRAP_CONTENT));
}
listItem.measure(desiredWidth, MeasureSpec.UNSPECIFIED); // this is where the exception happens
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight + (listView.getItemMargin() * (listAdapter.getCount() - 1)) + listView.getPaddingTop() + listView.getPaddingBottom();
listView.setLayoutParams(params);
listView.requestLayout();
}
Here's the stack trace:
java.lang.NullPointerException
at android.text.StaticLayout.<init>(StaticLayout.java:50)
at android.support.v7.widget.SwitchCompat.makeLayout(SwitchCompat.java:606)
at android.support.v7.widget.SwitchCompat.onMeasure(SwitchCompat.java:526)
at android.view.View.measure(View.java:15395)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4826)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1396)
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1038)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:576)
at android.view.View.measure(View.java:15395)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4826)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1396)
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1038)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:576)
at android.view.View.measure(View.java:15395)
Upvotes: 0
Views: 1022
Reputation: 147
In Method onMeasue of SwtichCompat, if showText is true, it will make layout with textOn and textOff:
@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
if (mShowText) {
if (mOnLayout == null) {
mOnLayout = makeLayout(mTextOn);
}
if (mOffLayout == null) {
mOffLayout = makeLayout(mTextOff);
}
}
...
}
Have a look at method makeLayout:
private Layout makeLayout(CharSequence text) {
final CharSequence transformed = (mSwitchTransformationMethod != null)
? mSwitchTransformationMethod.getTransformation(text, this)
: text;
return new StaticLayout(transformed, mTextPaint,
transformed != null ?
(int) Math.ceil(Layout.getDesiredWidth(transformed, mTextPaint)) : 0,
Layout.Alignment.ALIGN_NORMAL, 1.f, 0, true);
}
If the param text is null, transformed will be null too. Then it will be passed to the constructor of StaticLayout, causing NullPointException.
So, you should set the attributes android:textOn and android:textOff for SwitchCompat, or set app:showText="false":
<android.support.v7.widget.SwitchCompat
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textOn="@string/text_on"
android:textOff="@string/text_off" />
or
<android.support.v7.widget.SwitchCompat
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:showText="false" />
Upvotes: 2
Reputation: 1702
SwitchCompat requires you to specify android:textOn and android:textOff
example, you can change like this
<android.support.v7.widget.SwitchCompat
android:id="@+id/on_off_switch"
android:textOn="On"
android:textOff="Off"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_centerVertical="true"
android:layout_alignParentEnd="true"/>
Upvotes: 0