android - custom view has width and height of 0

Question

I'm trying to create a custom view with two TextViews inside a vertical LinearLayout, but am totally confused as to how it all works.

Currently nothing is appearing as I my onDraw method isn't being called. I think this is due to the fact that my view (the LinearLayout?) has a width and height of both 0.

I think I should be overwriting my onMeasure, but after trying setMeasuredDimension(100,100) this still isn't working.

I am trying to inflate an xml inside the view and use the two TextViews in that.

An explanation would also be great so I can hopefully get my head around how this all works.

Thanks

size_button.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >

<TextView
    android:id="@+id/sizeButtonSizeText"
    android:layout_width="wrap_content"
    android:layout_height="match_parent" />

<TextView
    android:id="@+id/sizeButtonSlugText"
    android:layout_width="wrap_content"
    android:layout_height="match_parent" />

</LinearLayout>

SizeButton.java

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View.MeasureSpec;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.nap.library.NapApplication;
import com.nap.library.R;

public class SizeButton extends LinearLayout {

    private TextView mSize;
    private TextView mSlug;
    private String mSizeText;
    private String mSlugText;
    private Paint mPaint;
    private boolean mSoldOut;
    private Context mContext;

    /*
    public SizeButton(Context context) {
        super(context);
        setup();
    }

    public SizeButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        setup();
    }
    */

    public SizeButton(Context context, String size, String slug) {
        super(context);
        mContext = context;
        mSizeText = size;
        mSlugText = slug;
        setup();
    }

    public void setSoldOut(){
        this.mSoldOut = true;
    }

    public boolean isSoldOut(){
        return mSoldOut;
    }

    public void setSizeText(String size){
        mSize.setText(size);
    }

    public void setSlugText(String slug){
        mSlug.setText(slug);
    }

    public void setup(){
        mPaint = new Paint();


        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        LinearLayout buttonLayout = (LinearLayout) inflater.inflate(R.layout.size_button, null);
        mSize = (TextView) buttonLayout.findViewById(R.id.sizeButtonSizeText);
        mSize.setGravity(Gravity.CENTER);
        mSize.setTextColor(Color.BLACK);
        mSize.setText(mSizeText);
        mSize.setTypeface(NapApplication.mPorter);
        mSize.setWidth(10);
        mSlug = (TextView) buttonLayout.findViewById(R.id.sizeButtonSlugText);
        mSlug.setGravity(Gravity.CENTER);
        mSlug.setTextColor(Color.BLACK);
        mSlug.setText(mSlugText);
        mSlug.setTypeface(NapApplication.mPorter);
        invalidate();
        requestLayout();

        LinearLayout.LayoutParams layoutParams =  new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
        mSize.setLayoutParams(layoutParams);
        mSlug.setLayoutParams(layoutParams);
        Log.i("button","in setup");
        Log.i("button","width = "+this.getWidth()+" height = "+this.getHeight());
        Log.i("button","width = "+mSize.getWidth()+" sizeheight = "+mSize.getHeight());
        Log.i("button","width = "+mSlug.getWidth()+" slugheight = "+mSlug.getHeight());
  }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.i("button","in onMeasure");
        setMeasuredDimension(100,100);
    }


    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Log.i("button","in ondraw");
    }


}

ProductFragment.java - where the button is added to the fragment

for (int i = 0; i < mItem.getSizes().length; i++) {
    final SizeButton sizeButton = new SizeButton(getActivity(),mItem.getSizes()[i],"hello");

    // Each size button has a sku set as its tag
    sizeButton.setTag(mItem.getSkus()[i]);
    sizeButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            if(mItem.getSizes().length > 1) {
            boolean selected = !sizeButton.isSelected();
            if (selected) {
                mCurrentSku = (String) v.getTag();
            } else {
                mCurrentSku = null;
            }
            }
        configureButtons();
        }
    });
    Log.e("button","Adding button to view");
    mSizesWrapper.addView(sizeButton);
}

Answer 1

As your are extending a ViewGroup, you should override dispatchDraw(), not onDraw()