自定义View回掉函数

备注：

onMeasure:指定相关view的测量模式
onSizeChanged:获取相关尺寸参数
onFinishInflate:可以用来获取指定的view组件

code:

public class Demo extends View {
    public Demo(Context context) {
        super(context);
    }

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

    public Demo(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        Log.d("Demo","onSizeChanged");
        super.onSizeChanged(w, h, oldw, oldh);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.d("Demo","onMeasure");
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    protected void onFinishInflate() {
        Log.d("Demo","onFinishInflate");
        super.onFinishInflate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Log.d("Demo","onDraw");
        super.onDraw(canvas);
    }

    @Override
    protected void onAttachedToWindow() {
        Log.d("Demo","onAttachedToWindow");
        super.onAttachedToWindow();
    }
}

result:

onFinishInflate
Activity onCreate
Activity onStart
Activity onResume
onAttachedToWindow
onMeasure
onMeasure
onMeasure
onMeasure
onSizeChanged
onDraw
onMeasure
onMeasure
onDraw