Android: How can I add childs to my custom ViewGroup with a CursorAdapter ?

Question

Please help! I tried everything! :(

I've got a schedule Class, which is simply a custom ViewGroup (with custom onMeasure() and onLayout()), which enables me to place childs(=events) with LayoutParams for column/row start and column/row end. The number of childs and their LayoutParams depend on database entries.

Now I'm trying to add childs (events) from my database. I'd have to use a Cursor Adapter, so my schedule Class has to extend ListView, right? I tried that but the newView() method of the adapter is never called. Why not?? My custom ListView doesn't ask the adapter for childs, no childs are added. I also can't add the childs by hand calling schedule.addView() if I extend from AdapterView.

I'd be really (really) happy if someone could help!

Regards, cody

This is my custom ViewGroup:

public class Schedule extends ViewGroup {
private int columns;
private int rows;
private float preferredCellWidth;
private float preferredCellHeight;
private String[] rowTimes;
private Paint paint;

public Schedule(Context context, int columns, int rows, float preferredCellWidth, float preferredCellHeight, String[] rowTimes) {
    super(context);
    this.columns = columns;
    this.rows = rows;
    this.preferredCellWidth = preferredCellWidth;
    this.preferredCellHeight = preferredCellHeight;
    this.rowTimes = rowTimes;
    init(context);
}

private void init(Context context) {
    Log.i("Schedule", "initSchedule...");
    setPaint();
    setWillNotDraw(false);
}

private void setPaint() {
    paint = new Paint();
    paint.setTextSize(preferredCellHeight*2/3);
    paint.setStyle(Paint.Style.STROKE);
    paint.setColor(getResources().getColor(R.color.white));
}

public Schedule(Context context, AttributeSet attrs) {
    super(context, attrs);
    readAttr(context, attrs);
    init(context);
}

public Schedule(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    readAttr(context, attrs);
    init(context);
}

private void readAttr(Context c, AttributeSet attrs) {
    android.content.res.TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.ScheduleLayout);
    this.columns = a.getInt(R.styleable.ScheduleLayout_columns, 1);
    this.rows = a.getInt(R.styleable.ScheduleLayout_rows, 1);
    this.preferredCellWidth = a.getDimension(R.styleable.ScheduleLayout_preferredCellWidth, 1);
    this.preferredCellHeight = a.getDimension(R.styleable.ScheduleLayout_preferredCellHeight, 1);
    a.recycle();
}

@Override
protected void onDraw(Canvas canvas) {
    //Log.i(this.toString(),"onDraw ..."+" this.getLeft()="+this.getLeft()+", this.getWidth()="+this.getWidth());
    super.onDraw(canvas);
    for (int i = 0; i < rows; i++) {
        int line = (int) Math.round(this.getTop()+ (i+1) * preferredCellHeight);
        canvas.drawText(this.rowtimes[i], this.getLeft()+5, line-3, paint);
        canvas.drawLine(this.getLeft(), line, this.getWidth(), line, paint);
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    Log.i("Schedule", "onMeasure...");
    float width = (MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight()) / columns;
    float height = (MeasureSpec.getSize(heightMeasureSpec) - getPaddingTop() - getPaddingBottom()) / rows;
    float cellWidth = preferredCellWidth;
    float cellHeight = preferredCellHeight;

    if (MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.EXACTLY) {
        cellWidth = width;
    } else if (MeasureSpec.getMode(widthMeasureSpec) == MeasureSpec.AT_MOST) {
        cellWidth = Math.min(preferredCellWidth, width);
    }

    if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.EXACTLY) {
        cellHeight = height;
    } else if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
        cellHeight = Math.min(preferredCellHeight, height);
    }

    for (int i = 0; i < getChildCount(); i++) {
        View child = getChildAt(i);
        if (child.getVisibility() != GONE) {
            LayoutParams lp = (LayoutParams) child.getLayoutParams();
            int cwidth = (int) Math.round(cellWidth * lp.getWidth());
            int cheight = (int) Math.round(cellHeight * lp.getHeight());
            child.measure(
                    MeasureSpec.makeMeasureSpec(cwidth, MeasureSpec.EXACTLY),
                    MeasureSpec.makeMeasureSpec(cheight, MeasureSpec.EXACTLY)
            );
        }
    }
    setMeasuredDimension(
            (int) Math.round(cellWidth * columns + getPaddingLeft() + getPaddingRight()),
            (int) Math.round(cellHeight    * rows + getPaddingTop() + getPaddingBottom())
    );
}

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    if (!changed)
        return;

    int cellWidth = ((r-l) - getPaddingLeft() - getPaddingRight()) / columns;
    int cellHeight = ((b-t) - getPaddingTop() - getPaddingBottom()) / rows;

    for (int i = 0; i < getChildCount(); i++) {
        View child = getChildAt(i);

        if (child.getVisibility() != GONE) {
            LayoutParams lp = (LayoutParams) child.getLayoutParams();
            int cl = (int) Math.round(getPaddingLeft() + lp.columnStart    * cellWidth);
            int cr = (int) Math.round(getPaddingLeft() + lp.columnEnd * cellWidth);
            int ct = (int) Math.round(getPaddingTop() + lp.rowStart    * cellHeight);
            int cb = (int) Math.round(getPaddingTop() + lp.rowEnd * cellHeight);
            child.layout(cl, ct, cr, cb);
        }
    }
}

protected boolean checkLayoutParams(android.view.ViewGroup.LayoutParams p) {
    Log.i("Schedule", "checkLayoutParams...");
    if (p instanceof LayoutParams) {
        LayoutParams lp = (LayoutParams) p;
        if (lp.columnEnd > columns || lp.columnStart < 0)
            return false;
        if (lp.rowEnd > rows || lp.rowStart < 0)
            return false;
        return lp.columnEnd > lp.columnStart && lp.rowEnd > lp.rowStart;
    } else
        return false;
}

public android.widget.AbsListView.LayoutParams generateLayoutParams(AttributeSet attrs) {
    return new android.widget.AbsListView.LayoutParams(getContext(), attrs);
}

public static class LayoutParams extends android.view.ViewGroup.LayoutParams {
    public int columnStart;
    public int columnEnd;
    public int rowStart;
    public int rowEnd;

    public LayoutParams(int columnStart, int rowStart, int columnEnd, int rowEnd) {
        super(WRAP_CONTENT, WRAP_CONTENT);
        this.columnStart = columnStart;
        this.columnEnd = columnEnd;
        this.rowStart = rowStart;
        this.rowEnd = rowEnd;
    }

    public LayoutParams(Context c, AttributeSet attrs) {
        super(WRAP_CONTENT, WRAP_CONTENT);
        android.content.res.TypedArray a = c.obtainStyledAttributes(attrs, R.styleable.EventLayout);
        this.columnStart = a.getInt(R.styleable.EventLayout_event_columnStart, 0);
        this.columnEnd = a.getInt(R.styleable.EventLayout_event_columnEnd,    this.columnStart + 1);
        this.rowStart = a.getInt(R.styleable.EventLayout_event_rowStart, 0);
        this.rowEnd = a.getInt(R.styleable.EventLayout_event_rowEnd, this.rowStart + 1);
        a.recycle();
    }

    public int getWidth() {
        return columnEnd - columnStart;
    }

    public int getHeight() {
        return rowEnd - rowStart;
    }
}

And this is the event-layout - event.xml:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:orientation="vertical"
android:gravity="center" >

    <TextView android:id="@+id/text_event_name"
    style="@style/Event_TextView1" />

    <TextView android:id="@+id/text_event_name2"
    style="@style/Event_TextView2" />

</LinearLayout>

<TextView android:id="@+id/text_event_weeks"
style="@style/Event_TextView2"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true" />

<TextView android:id="@+id/text_event_room"
style="@style/Event_TextView2"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true" />

In my Activity I've got that code:

Schedule schedule = new Schedule(this, 4, rowTimes.length, 15, 15, rowTimes);

Cursor cursor = dbManager.getEvents(day); MySimpleCurserAdapter adapter = ... ?? // schedule.setAdapter not working...

How can I add events to the schedule with the data from the cursor?

Answer 1

You should not need to be extending ListView. You just want to add an instance of ListView to your layout.

It sounds like you might want to be using a SimpleCursorAdaptor, where you can map items in your custom view to the data model objects you want them to display.

See Binding to Data with Adapter and Hello ListView for some examples of the right ways to use adapters and ListViews.