Custom linear layout

Question

I'm trying to make my own LinearLayout to make it reusable and modular. first my code looked like this, which worked fine:

mLlHeader = (LinearLayout)view.findViewById(R.id.ll_header);
        mTvCrump = new TextView(mContext);
        mTvCrump.setText("> "+((Item) mNavigationHistory.get(mNavigationHistory.size()-1)).getName());
        mTvCrump.setId(mNavigationHistory.size()-1);
        mTvCrump.setClickable(true);
        mTvCrump.setOnClickListener(mBreadcrumpListener);
        mBreadcrump.add(mTvCrump);
        mLlHeader.addView(mTvCrump,mNavigationHistory.size()-1);

Now i want to make my own LinearLayout class like this:

public class Breadcrump extends LinearLayout {

    private List<? super Item> mNavigationHistory = new ArrayList<Item>();
    private List<TextView> mElements = new ArrayList<TextView>();

    public Breadcrump(Context context) {
        super(context);
    }

    public Breadcrump(Context context, AttributeSet attrs) {
    super(context, attrs);
}

    public void addElement (String name) {

    }

}

my xml looks like this:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/cell_selected"
    android:gravity="left"
    android:orientation="vertical"
    android:padding="5dp" >

      <com.client.views.Breadcrump
        android:id="@+id/ll_breadcrump"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" /> 
</LinearLayout>

and use it like this:

mLlHeader = (Breadcrump)view.findViewById(R.id.ll_breadcrump);
....

EDIT

i now added the namespace in the layout xml file where i use my custom view and a new Constructor in the view class with an attribute set. Now the app starts. But it displays only my custom view and the rest of the layout is white ?

Answer 1

In your layout XML file, you probably have something like this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/ll_header"
    ... />

Try changing it to

<?xml version="1.0" encoding="utf-8"?>
<com.client.views.Breadcrump
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/ll_header"
    ... />

EDIT: how to use it in your activity?

If your XML layout file is called main.xml , then just call setContentView(R.layout.main) in the onCreate() method of your activity. Your Breadcrump gets initialized internally. Then you can get a reference to it with (Breadcrump)view.findViewById(R.id.ll_header) .