介紹anroid通過繼承系統的控件自定義view

方法是通過對OnDraw（）方法進行復寫來實現的

舉例繼承TextView

在textView的背景加上矩形的效果

代碼實現

testView的代碼

public class TestView extends TextView {

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

    @Override
    protected void onDraw(Canvas canvas) {
        Paint paint1 = new Paint();
        paint1.setColor(getResources().getColor(android.R.color.holo_blue_light));
        paint1.setStyle(Paint.Style.FILL);
        Paint paint2 = new Paint();
        paint2.setColor(Color.YELLOW);
        paint2.setStyle(Paint.Style.FILL);
        canvas.drawRect(0,0,getMeasuredWidth(),getMeasuredHeight(),paint1);
        canvas.drawRect(10,10,getMeasuredWidth()-10,getMeasuredHeight()-10,paint2);
        canvas.save();
        canvas.translate(10,0);
        super.onDraw(canvas);
        canvas.restore();
    }
}

布局的代碼

public class TestView extends TextView {

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

    @Override
    protected void onDraw(Canvas canvas) {
        Paint paint1 = new Paint();
        paint1.setColor(getResources().getColor(android.R.color.holo_blue_light));
        paint1.setStyle(Paint.Style.FILL);
        Paint paint2 = new Paint();
        paint2.setColor(Color.YELLOW);
        paint2.setStyle(Paint.Style.FILL);
        canvas.drawRect(0,0,getMeasuredWidth(),getMeasuredHeight(),paint1);
        canvas.drawRect(10,10,getMeasuredWidth()-10,getMeasuredHeight()-10,paint2);
        canvas.save();
        canvas.translate(10,0);
        super.onDraw(canvas);
        canvas.restore();
    }
}