在Android中使用“自定义视图”加载器动画

Question

将此问题发布在CodeReview上，但没有得到太多回应。 链接到代码审查链接

我为Android应用程序创建了一个加载器动画：一个简单的3点加载器。

这是工作。 但这是使用TimerTask进行动画制作的正确方法吗？

public class ThreeDotsLoader extends View {

Paint dot1;
Paint dot2;
Paint dot3;

int defaultColor;
int highlightColor;

boolean animationStarted = false;

TimerTask task;
Timer timer;

int count = 1;

public ThreeDotsLoader(Context context, AttributeSet attrs) {
    super(context, attrs);
    defaultColor = Color.rgb(44, 78, 82);
    highlightColor = Color.WHITE;

    initPaint();
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Log.d("custom", "ondraw");
    canvas.drawCircle(50, 50, 15, dot1);
    canvas.drawCircle(100, 50, 15, dot2);
    canvas.drawCircle(150, 50, 15, dot3);
}

private void initPaint(){
    dot1 = new Paint();
    dot1.setColor(defaultColor);
    dot1.setStyle(Paint.Style.FILL);
    dot1.setAntiAlias(true);


    dot2 = new Paint();
    dot2.setColor(defaultColor);
    dot2.setStyle(Paint.Style.FILL);
    dot2.setAntiAlias(true);

    dot3 = new Paint();
    dot3.setColor(defaultColor);
    dot3.setStyle(Paint.Style.FILL);
    dot3.setAntiAlias(true);
}

public void startLoading(){
    task = new TimerTask() {

        @Override
        public void run() {

            switch(count){
            case 1:
                dot1.setColor(highlightColor);
                dot2.setColor(defaultColor);
                dot3.setColor(defaultColor);
                count++;
                break;
            case 2:
                dot1.setColor(defaultColor);
                dot2.setColor(highlightColor);
                dot3.setColor(defaultColor);
                count++;
                break;
            case 3:
                dot1.setColor(defaultColor);
                dot2.setColor(defaultColor);
                dot3.setColor(highlightColor);
                count = 1;
                break;
            }
            animationStarted = true;
            postInvalidate();
        }
    };
    timer = new Timer();
    timer.schedule(task, 0, 300);

}

public void stopLoading(){
    animationStarted = false;
    timer.cancel();
}
}

Answer 1

我建议使用Handler有一些优点

While rescheduling Handler is very easy, you can not reschedule Timer    

In Handler you can attach to any Runnable but Timer schedule for only one TimerTask

TimerTask is purely background task so you can not update UserInterface, but that's not true for Handler's Runnables