自定义TextView-在构造函数之前调用的setText() [英] Custom TextView - setText() called before constructor
问题描述
我的 CustomTextView 出现问题.我试图从我的 这是我的代码(细分为相关部分):layout-xml
文件中获取一个自定义值,并在我的setText()
方法中使用它.不幸的是, setText()方法在构造方法之前被调用,因此,我无法在此方法中使用自定义值.>
CustomTextView.class
public class CustomTextView extends TextView {
private float mHeight;
private final String TAG = "CustomTextView";
private static final Spannable.Factory spannableFactory = Spannable.Factory.getInstance();
public CustomTextView(Context context, AttributeSet attrs) {
super(context, attrs);
Log.d(TAG, "in CustomTextView constructor");
TypedArray values = context.obtainStyledAttributes(attrs, R.styleable.CustomTextView);
this.mHeight = values.getDimension(R.styleable.CustomTextView_cHeight, 20);
}
@Override
public void setText(CharSequence text, BufferType type) {
Log.d(TAG, "in setText function");
Spannable s = getCustomSpannableString(getContext(), text);
super.setText(s, BufferType.SPANNABLE);
}
private static Spannable getCustomSpannableString(Context context, CharSequence text) {
Spannable spannable = spannableFactory.newSpannable(text);
doSomeFancyStuff(context, spannable);
return spannable;
}
private static void doSomeFancyStuff(Context context, Spannable spannable) {
/*Here I'm trying to access the mHeight attribute.
Unfortunately it's 0 though I set it to 24 in my layout
and it's correctly set in the constructor*/
}
}
styles.xml
<declare-styleable name="CustomTextView">
<attr name="cHeight" format="dimension"/>
</declare-styleable>
layout.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:ctvi="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.mypackage.views.CustomTextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/my_fancy_string"
android:textSize="16sp"
ctvi:cHeight="24dp" />
</LinearLayout>
作为证明-这是LogCat的输出:
30912-30912/com.mypackage.views D/CustomTextView﹕ in setText function
30912-30912/com.mypackage.views D/CustomTextView﹕ in CustomTextView constructor
因此您可以看到setText()
方法在构造函数之前被调用.有点奇怪,我不知道要在setText方法中使用自定义属性(cHeight
),需要更改什么.
在此先感谢您的帮助!
是TextView
super()
构造函数,它根据属性值调用setText()
.
如果在设置文本值时确实需要访问自定义属性,请对文本也使用自定义属性.
I've got a problem with my CustomTextView. I'm trying to get a custom value from my layout-xml
file and use this in my setText()
method. Unfortunately the setText() method gets called before the constructor and because of this I can't use the custom value in this method.
Here's my code (broken down to the relevant parts):
CustomTextView.class
public class CustomTextView extends TextView {
private float mHeight;
private final String TAG = "CustomTextView";
private static final Spannable.Factory spannableFactory = Spannable.Factory.getInstance();
public CustomTextView(Context context, AttributeSet attrs) {
super(context, attrs);
Log.d(TAG, "in CustomTextView constructor");
TypedArray values = context.obtainStyledAttributes(attrs, R.styleable.CustomTextView);
this.mHeight = values.getDimension(R.styleable.CustomTextView_cHeight, 20);
}
@Override
public void setText(CharSequence text, BufferType type) {
Log.d(TAG, "in setText function");
Spannable s = getCustomSpannableString(getContext(), text);
super.setText(s, BufferType.SPANNABLE);
}
private static Spannable getCustomSpannableString(Context context, CharSequence text) {
Spannable spannable = spannableFactory.newSpannable(text);
doSomeFancyStuff(context, spannable);
return spannable;
}
private static void doSomeFancyStuff(Context context, Spannable spannable) {
/*Here I'm trying to access the mHeight attribute.
Unfortunately it's 0 though I set it to 24 in my layout
and it's correctly set in the constructor*/
}
}
styles.xml
<declare-styleable name="CustomTextView">
<attr name="cHeight" format="dimension"/>
</declare-styleable>
layout.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:ctvi="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.mypackage.views.CustomTextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/my_fancy_string"
android:textSize="16sp"
ctvi:cHeight="24dp" />
</LinearLayout>
And just as a proof - here's the LogCat output:
30912-30912/com.mypackage.views D/CustomTextView﹕ in setText function
30912-30912/com.mypackage.views D/CustomTextView﹕ in CustomTextView constructor
So as you can see the setText()
method is called before the constructor. That's kinda weird and I don't know what I need to change in order to use my custom attribute (cHeight
) in the setText-method.
Thanks in advance for any help!
It's the TextView
super()
constructor that calls your setText()
based on the attribute values.
If you really need to access your custom attribute when setting a text value, use a custom attribute for the text as well.
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