android - 添加 fragment 时从汉堡包到箭头图标的过渡动画

我已经实现了主/细节流，我想在添加 fragment 后获得从汉堡包图标到箭头图标的过渡动画(与打开抽屉导航时的动画相同)。

我正在使用如下代码:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);

    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    toggle = new ActionBarDrawerToggle(this, drawer, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.setDrawerIndicatorEnabled(true);
    toggle.syncState();

    //Add home page fragment
    FragmentManager fragmentManager = getFragmentManager();
    HabitHomeFragment homePageFragment = new HabitHomeFragment();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.replace(R.id.habit_home, homePageFragment);
    fragmentTransaction.commit();}

在添加细节 fragment 时:

public void showDetails() {
        toggle.setDrawerIndicatorEnabled(false);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        fragmentTransaction.replace(R.id.habit_home, habitDetailsFragment).addToBackStack("detail").commit();}

和工具栏:

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>
....

目前在更改 fragment 后，图标只是更改，没有动画。

最佳答案

先做一些解释。

android.support.v7.app.ActionBarDrawerToggle 使用特殊的 drawable 类来制作汉堡到箭头的图标和动画。

类是 android.support.v7.graphics.drawable.DrawerArrowDrawable

DrawerArrowDrawable 使用 setProgress(float progress) 方法实现动画，其中进度从 0(汉堡包)到 1(箭头)。

ActionBarDrawerToggle 使用调用 private void setPosition(float position)

的 DrawerArrowDrawable.setProgress()

ActionBarDrawerToggle 使用public void onDrawerSlide(View drawerView, float slideOffset) 调用私有(private)setPosition()

ActionBarDrawerToggle 在构造函数中调用 toolbar.setNavigationOnClickListener() 及其监听器，用于切换抽屉。

ActionBarDrawerToggle 跟踪实际的 DrawerArrowDrawable 状态。 Toolbar 和 ActionBar 不跟踪实际的 DrawerArrowDrawable 状态。

那么，你应该在 Activity 中做什么。选项-A，使用 ActionBarDrawerToggle。

    // define a variable to track hamburger-arrow state
    protected boolean isHomeAsUp = false;

    protected DrawerLayout drawer;
    protected Toolbar toolbar;
    protected ActionBarDrawerToggle toggle;

    // I've implemented it in setContentView(), but you can implement it in onCreate()
    @Override
    public void setContentView(@LayoutRes int layoutResID) {
        super.setContentView(layoutResID);

        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        toggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.drawer_open, R.string.drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        // overwrite Navigation OnClickListener that is set by ActionBarDrawerToggle
        toolbar.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (drawer.isDrawerOpen(GravityCompat.START)){
                    drawer.closeDrawer(GravityCompat.START);
                } else if (isHomeAsUp){
                    onBackPressed();
                } else {
                    drawer.openDrawer(GravityCompat.START);
                }
            }
        });
    }

    // call this method for animation between hamburged and arrow
    protected void setHomeAsUp(boolean isHomeAsUp){
        if (this.isHomeAsUp != isHomeAsUp) {
            this.isHomeAsUp = isHomeAsUp;

            ValueAnimator anim = isHomeAsUp ? ValueAnimator.ofFloat(0, 1) : ValueAnimator.ofFloat(1, 0);
            anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator valueAnimator) {
                    float slideOffset = (Float) valueAnimator.getAnimatedValue();
                    toggle.onDrawerSlide(drawer, slideOffset);
                }
            });
            anim.setInterpolator(new DecelerateInterpolator());
            // You can change this duration to more closely match that of the default animation.
            anim.setDuration(400);
            anim.start();
        }
    }

或者，您可以使用 DrawerArrowDrawable 将 toolbar.setNavigationIcon() 设置为导航图标，并在没有 ActionBarDrawerToggle 的情况下对其进行动画处理
见选项-B:https://stackoverflow.com/a/42024138/1148784