Question

我要做的是制作尺寸和尺寸的动画。 ImageView上的职位变更。为此，我使用以下方法：

void doAnimation() {
    ImageView logo = findViewById(R.id.logo);
    float scaleVal = R.attr.actionBarSize / logo.getHeight(); // Finds the scale needed to make the logo as tall as the actionBar

    // Gets the width and height in dp
    DisplayMetrics displayMetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
    float density = getResources().getDisplayMetrics().density;
    float dpH = displayMetrics.heightPixels / density;
    float dpW = displayMetrics.widthPixels / density;

    // The final X and Y in dp
    float finalX = dpW - (logo.getWidth() / density) - 16;
    float finalY = dpH - (logo.getHeight() / density) - 16;

    // The final X and Y converted to %
    float finalXPercentage = finalX / dpW;
    float finalYPercentage = finalY / dpH;

    logo.animate()
        .setDuration(750)
        .scaleX(scaleVal)
        .scaleY(scaleVal)
        .translationX(finalXPercentage)
        .translationY(finalYPercentage);
}

我从doAnimation()方法调用onResume()方法，但由于显而易见的原因，我无法在getHeight()方法中使用getWidth()或onResume()

问题是我不知道徽标的高度或宽度，因为我正在使用ConstraintLayout，因此我没有指定宽度或高度。我想要做的是将ImageView移动到右上角（距离它有16dp的空间）并将其调整为与ActionBar（工具栏）高度一样高。

Answer 1

你能否在onLayoutChange内尝试这个。我解决了这个问题。

logo.addOnLayoutChangeListener(new OnLayoutChangeListener() {
    @Override
    public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
        mLayout.removeOnLayoutChangeListener(this);
        doyourAnimationcodehere();
    }
});

Answer 2

您可以尝试使用View.Post()

void doAnimation() {
    ImageView logo = findViewById(R.id.logo);

    // new Runnable() can be substituted with () -> if you are using Java 8
    logo.post(new Runnable() { 
        @Override
        public void run() {
            DisplayMetrics displayMetrics = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
            float density = getResources().getDisplayMetrics().density;

            // Finds the scale needed to make the logo as tall as the actionBar
            float scaleVal = 56 / (logo.getHeight() / density);

            // Gets the width and height in dp
            float width = displayMetrics.widthPixels / density;
            float height = displayMetrics.heightPixels;

            // The final X and Y in dp
            float finalX = logo.getX() + width / 2;

            logo.animate()
                    .setDuration(ANIMATION_DURATION)
                    .scaleX(scaleVal).scaleY(scaleVal)
                    .xBy(finalX).y(0);
        }
    });
}

如何在您不知道其尺寸时移动视图？

2 个答案: