java - 通过动画过渡动态更改背景颜色

Question

我正在尝试以 3 秒的速度生成随机颜色并将其设置为背景。我创建了一个线程来处理此更改，现在我想在颜色更改之间添加过渡以使其很好地混合。

作为引用，请查看 this app .

编辑:我尝试过在一个具有 3 秒过渡周期的循环中使用 ObjectAnimator 和 ArgbEvaluator，但是屏幕一直以类似频闪的方式闪烁，这只会给您一个头痛。除此之外，颜色变化得很好，其他一切都很完美。有人可以运行这个并看看可能出了什么问题吗？

public class Main extends Activity {

public int color1, color2, red1, red2, blue1, blue2, green1, green2;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.main);


    new Thread() {
        public void run() {
            while(true) {
                try {
                    Thread.sleep(3000); // I've also tried 1000 and 4000, same issue.
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                Main.this.runOnUiThread(new Runnable() {
                    public void run() {

                    //generate color 1
                        red1 = (int)(Math.random() * 128 + 127);
                        green1 = (int)(Math.random() * 128 + 127);
                        blue1 = (int)(Math.random() * 128 + 127);
                        color1 = 0xff << 24 | (red1 << 16) |
                                (green1 << 8) | blue1;


                    //generate color 2

                        red2 = (int)(Math.random() * 128 + 127);
                        green2 = (int)(Math.random() * 128 + 127);
                        blue2 = (int)(Math.random() * 128 + 127);
                        color2 = 0xff << 24 | (red2 << 16) |
                                (green2 << 8) | blue2;

                    //start animation
                        View v = findViewById(R.id.view);
                        ObjectAnimator anim = ObjectAnimator.ofInt(v, "backgroundColor", color1, color2);


                        anim.setEvaluator(new ArgbEvaluator());
                        anim.setRepeatCount(ValueAnimator.INFINITE);
                        anim.setRepeatMode(ValueAnimator.REVERSE);
                        anim.setDuration(3000);
                        anim.start();

                    }
                });
            }
        }
    }.start();
}

}

编辑:我缩小了范围，发现“.setRepeatMode”导致了问题。我仍然没有解决办法。通过将“反向”更改为其他内容(无限或其他提供的选项)，可以防止动画发生。知道我能做些什么来解决这个问题吗？

另外，有人知道更好的方法来生成更鲜艳的颜色吗？我研究的一切都已经过时了。

Answer 1

除了一件事之外，您所做的一切都是正确的:每 3 秒，您就会随机生成 2 种颜色。所以，这就是正在发生的事情:

1st iteration:

color1 is generated

color2 is generated

View's background is set to color1. And then the background changes from color1 to color2.

// All's good

2nd iteration:

There's a new color1

There's a new color2

View's background is set to new color1. Immediate change causes the strobe light effect. And then the background changes from new color1 to new color2.

您应该采取什么措施来解决此问题:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.main);

    // Generate color1 before starting the thread
    red1 = (int)(Math.random() * 128 + 127);
    green1 = (int)(Math.random() * 128 + 127);
    blue1 = (int)(Math.random() * 128 + 127);
    color1 = 0xff << 24 | (red1 << 16) |
                          (green1 << 8) | blue1;


    new Thread() {
        public void run() {
            while(true) {
                try {
                    Thread.sleep(3000); 
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                Main.this.runOnUiThread(new Runnable() {
                    public void run() {

                    //generate color 2

                        red2 = (int)(Math.random() * 128 + 127);
                        green2 = (int)(Math.random() * 128 + 127);
                        blue2 = (int)(Math.random() * 128 + 127);
                        color2 = 0xff << 24 | (red2 << 16) |
                                (green2 << 8) | blue2;

                    //start animation
                        View v = findViewById(R.id.view);
                        ObjectAnimator anim = ObjectAnimator.ofInt(v, "backgroundColor", color1, color2);


                        anim.setEvaluator(new ArgbEvaluator());
                        anim.setRepeatCount(ValueAnimator.INFINITE);
                        anim.setRepeatMode(ValueAnimator.REVERSE);
                        anim.setDuration(3000);
                        anim.start();

                        // Now set color1 to color2
                        // This way, the background will go from
                        // the previous color to the next color
                        // smoothly
                        color1 = color2;

                    }
                });
            }
        }
    }.start();
}

因此，从第二次迭代开始，起始颜色应与上一次迭代的结束颜色相同。仅初始化/生成 color1 一次:在启动线程之前。在 anim.start() 之后，添加:

color1 = color2;

另外，请注意，您将每 3 秒创建一个新的 ObjectAnimator:

ObjectAnimator anim = ObjectAnimator.ofInt(v, "backgroundColor", color1, color2);

因此，以下语句无效:

anim.setRepeatCount(ValueAnimator.INFINITE);
anim.setRepeatMode(ValueAnimator.REVERSE); 

这是我的建议:

public class Main extends Activity {

    public int color1, color2, red1, red2, blue1, blue2, green1, green2;

    View v;

    ObjectAnimator anim;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.main);

        // White or whatever color background R.id.view
        // has at the beginning
        color1 = 0xffffffff;

        v = findViewById(R.id.llMain);

        // We haven't initialized color2 yet. Will set this later
        anim = ObjectAnimator.ofInt(v, "backgroundColor", color1);

        anim.setEvaluator(new ArgbEvaluator());

        anim.setDuration(3000);


        new Thread() {
            public void run() {
                while(true) {
                    try {
                        Thread.sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    Main.this.runOnUiThread(new Runnable() {
                        public void run() {

                            //generate color 2

                            red2 = (int)(Math.random() * 128 + 127);
                            green2 = (int)(Math.random() * 128 + 127);
                            blue2 = (int)(Math.random() * 128 + 127);
                            color2 = 0xff << 24 | (red2 << 16) |
                                    (green2 << 8) | blue2;

                            // Update the color values
                            anim.setIntValues(color1, color2);

                            anim.start();

                            // Order the colors
                            color1 = color2;

                        }
                    });
                }
            }
        }.start();
    }
}

这样，您就创建了一次 ObjectAnimator 对象，并每 3 秒更新一次颜色值。