sinewave

SineView.java

import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;

/**
 * Created by rt12148 on 14/8/16.
 **/
public class SineView extends View {

    Path path = new Path();
    RectF rect = new RectF();

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

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

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

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public SineView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }


    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        rect = new RectF(0,0,w,h);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        setUp(canvas);
    }

    private void setUp(Canvas canvas) {
        path.moveTo(rect.left,rect.centerY());
        path.quadTo(rect.left + 50, rect.top, rect.left+ 100, rect.centerY());
        path.quadTo(rect.left + 150, rect.bottom, rect.left+ 200, rect.centerY());
        path.quadTo(rect.left + 250, rect.top, rect.left+ 300, rect.centerY());
        path.quadTo(rect.left + 350, rect.bottom, rect.left+ 400, rect.centerY());
        path.quadTo(rect.left + 450, rect.top, rect.left+ 500, rect.centerY());
        
        Paint paint = new Paint();
        paint.setStyle(Paint.Style.STROKE);
        canvas.drawPath(path,paint);
    }
}