I made my custom component just putting few TextViews together. Now I want to be able to init my custom control directly from code, passing text sizes independently for each of of TV's
My attributes definition:
<resources>
<declare-styleable name="BasicGauge">
<attr name="valueTextSize" format="dimension" />
<attr name="titleTextSize" format="dimension" />
<attr name="unitsTextSize" format="dimension" />
</declare-styleable>
</resources>
Sample initialization of component:
<pl.com.digita.BikeComputerUi.customviews.BasicGauge
android:id="@+id/basicGauge1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:padding="10dp"
valueTextSize="40sp">
</pl.com.digita.BikeComputerUi.customviews.BasicGauge>
How I try to read those attributes in component's constructor:
final int N = typedArray.getIndexCount();
for (int i = 0; i < N; i++) {
int attribute = typedArray.getIndex(i);
switch (attribute) {
case R.styleable.BasicGauge_valueTextSize:
valueTextSize = typedArray.getString(attribute);
break;
case R.styleable.BasicGauge_titleTextSize:
titleTextSize = typedArray.getString(attribute);
break;
case R.styleable.BasicGauge_unitsTextSize:
unitsTextSize = typedArray.getString(attribute);
break;
}
typedArray.recycle();
}
Problem: After creation all of my values are still null. 40sp is exactly my desired value.
A few things to say :
After that, it's not a very good idea to get a string, android offers more powerfull solution to deal with dimensions :
int unitsTextSize = typedArray.getDimensionPixelSize(R.styleable.BasicGauge_unitsTextSize, textSize);
then there are some subtleties :
paint.setTextSize(unitTextSize):
textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, unitTextSize);
The difference comes from what is called "raw pixels" (unscaled according to density, just raw) and "scaled pixels" (the opposite).
For a little more context to the accepted answer:
attrs.xml
Set the custom attribute with the dimension
format.
<resources>
<declare-styleable name="CustomView">
<attr name="valueTextSize" format="dimension" />
<attr name="titleTextSize" format="dimension" />
<attr name="unitsTextSize" format="dimension" />
</declare-styleable>
</resources>
activity.xml
Reference your attributes with xmlns:app=...
and set them in your xml with app:...
.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.example.myproject.CustomView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:valueTextSize="40sp"
app:titleTextSize="20sp"
app:unitsTextSize="24sp" />
</RelativeLayout>
CustomView.java
Obtain the values from the TypedArray using getDimensionPixelSize
. Within your custom view just work with pixels. See this answer if you need to convert to a different dimension.
public class CustomView extends View {
private float mValueTextSize; // pixels
private float mTitleTextSize; // pixels
private float mUnitsTextSize; // pixels
public CustomView(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.getTheme().obtainStyledAttributes(
attrs, R.styleable.CustomView, 0, 0);
try {
mValueTextSize = a.getDimensionPixelSize(R.styleable.CustomView_valueTextSize, 0);
mTitleTextSize = a.getDimensionPixelSize(R.styleable.CustomView_titleTextSize, 0);
mUnitsTextSize = a.getDimensionPixelSize(R.styleable.CustomView_unitsTextSize, 0);
} finally {
a.recycle();
}
}
// ...
}
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