java - 跟踪位置以动画 fragment 之间的过渡

Question

我正在将过渡应用于 fragment ，并且找到了适合我的需要的解决方案。在这里Fragment transition animations with BottomNavigationView

这是代码

private boolean loadFragment(Fragment fragment, int newPosition) {
if(fragment != null) {
    if(newPosition == 0) {
        getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.contentLayout, fragment).commit();

   }
    if(startingPosition > newPosition) {
        getSupportFragmentManager()
            .beginTransaction()
                .setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right )
            .replace(R.id.contentLayout, fragment).commit();

    }
    if(startingPosition < newPosition) {
        getSupportFragmentManager()
                .beginTransaction()
                .setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_left)
                .replace(R.id.contentLayout, fragment).commit();

    }
    startingPosition = newPosition;
    return true;
}

return false; }

startingPosition 无法解析，我不知道如何解决这个问题。

Answer 1

您必须在类中的函数上方定义startingPosition，如下所示:

int startingPosition = 0;
private boolean loadFragment(Fragment fragment, int newPosition) {
if(fragment != null) {
    if(newPosition == 0) {
        getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.contentLayout, fragment).commit();

   }
    if(startingPosition > newPosition) {
        getSupportFragmentManager()
            .beginTransaction()
                .setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right )
            .replace(R.id.contentLayout, fragment).commit();

    }
    if(startingPosition < newPosition) {
        getSupportFragmentManager()
                .beginTransaction()
                .setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_left)
                .replace(R.id.contentLayout, fragment).commit();

    }
    startingPosition = newPosition;
    return true;
}

return false; }