I am just trying to implement a customView from scratch i.e by extending the view class and overriding the onDraw() method. Just trying to build a simple view, a view which just draws a circle for now. I am facing some issue in aligning it and i am not able to understand how android is calculating the views dimensions. Just having only the view i.e setContentView(new MyCustomView(this)) works fine... it takes the entire space and draws the circle. But if i impose any constraints i.e giving margin, or aligning it in centreparent makes my view completely lost and it doesnt draw anything. The issue is the view is getting clipped by its parent but not able to understand why its getting clipped. Any help around this would be greatly appreciated. Here is my code.
Here is my customView
public class MyCustomView extends View {
private Paint myPaint=null;
private boolean useCenters;
private float xCoordinate;
private float yCoordinate;
private float viewWidth;
private float viewHeight;
private int totalTime;
private static float SWEEP_INC ;
private RectF myRect;
private boolean shouldInvalidate;
private float mSweep;
public MyCustomView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initPaintComponents();
}
public MyCustomView(Context context, AttributeSet attrs) {
this(context, attrs,0);
}
public MyCustomView(Context context) {
this(context,null);
}
private void initPaintComponents() {
myPaint = new Paint();
myPaint.setStyle(Paint.Style.STROKE);
myPaint.setStrokeWidth(4);
myPaint.setColor(0x880000FF);
useCenters = false;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
calculateCoordinates();
}
private void calculateCoordinates() {
xCoordinate = getX();
yCoordinate = getY();
viewWidth = getWidth();
viewHeight = getHeight();
myRect = new RectF(xCoordinate+3, yCoordinate+3, xCoordinate+viewWidth-(viewWidth/10), yCoordinate+viewHeight-(viewHeight/10));
Log.i("SAMPLEARC","xcoordinate: "+xCoordinate+" ycoordinate: "+yCoordinate+" view width:"+viewWidth+" view height:"+viewHeight+" measured width: "+getMeasuredWidth()+"measured height:"+getMeasuredHeight());
}
public int getTotalTime() {
return totalTime;
}
public void setTotalTime(int totalTime) {
this.totalTime = totalTime;
SWEEP_INC = (float)6/totalTime;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawArc(myRect, 0, mSweep, useCenters, myPaint);
mSweep += SWEEP_INC;
if(mSweep > 280)
{
myPaint.setColor(0x888800FF);
}
invalidate();
}
}
MyActivity:
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MyCustomView myView = (MyCustomView) findViewById(R.id.customimg);
myView.setTotalTime(10);
}
main.xml
RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@android:color/white"
com.example.anim.MyCustomView android:id="@+id/customimg"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_centerInParent="true"
if i remove that centerInParent in xml it gets drawn. so callling setMeasureDimentions() in onMeasure() doesnt have any affect either. But the xcoodinate,ycoordinate,viewWidth and viewHeight seems to give the correct values. Just need to understand why the view is getting clipped and how android is calculating the dimensions at runtime. And how do i consider the margin paramters while drawing these customViews. Any help would be greatly appreciated.
Thanks in advance
