Problems with inflating a composite component that extends a Layoutclass

问题

I'm trying to extend a LinearLayout to use as a composite component. I have followed this tutorial: link

Which seems fairly straight forward. However when I try to inflate my component it fails all the time. The error I get from logCat is that my class can't be found. It seems strange to me that as far as I can see android searches for my component among it's own components (I'm unsure about the correct wording here, please se below).

The code I have written is as follows:

main (the current activity):

//just the ordinary autogenerated eclipse code...
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
}

My extended linear layout:

public class DialPadView extends LinearLayout {

public DialPadView(Context ctx, AttributeSet attr) {
    super(ctx, attr);
}


@Override
protected void onFinishInflate() {
    super.onFinishInflate();
    ((Activity)getContext()).getLayoutInflater().inflate(R.layout.dialpadview, this);
}

}

My main.xml layout file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<whalenut.testinflate.DialPadView
    android:id="@+id/mydialpad"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    /></LinearLayout>

and finally my dialpadview.xml file to use with my composite component:

<?xml version="1.0" encoding="utf-8"?>
<DialPadView
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent">
   <EditText 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="test"/>
</DialPadView>

ofcourse all my class files resides in the package whalenut.testinflate

logCat says this:

java.lang.RuntimeException: Unable to start activity ComponentInfo{whalenut.testinflate/whalenut.testinflate.TestInflateActivity}: android.view.InflateException: Binary XML file line #2: Error inflating class DialPadView

...

Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class DialPadView

...

Caused by: java.lang.ClassNotFoundException: android.view.DialPadView in loader dalvik.system.PathClassLoader[/data/app/whalenut.testinflate-2.apk]

Why is Dalvik(?) searching for my class in the package android.view instead of whalenut.testinflate when I have given the fully qualified classname in the xml-file, is it because it doesn't find it there to begin with?

In short why can't I, or rather how do I inflate a extended Layout in android?

回答1:

You need to change your DialPadView as follows:

<merge android:class="com.packageName.UIClassName"
    android:id="@+id/DialView"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
<EditText android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="test"/>
</merge>

Then call this in your constructor:

super(context, attrs, defStyle);

LayoutInflater inflater = (LayoutInflater) context
    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

inflater.inflate(R.layout.DialView, this, true);

You can then use the following in your main activity:

DialView myDialView = new DialView(context);

mainView.addView(myDialView);

I hope this helps!

来源：https://stackoverflow.com/questions/7016821/problems-with-inflating-a-composite-component-that-extends-a-layoutclass

标签

android

components

composite