布局动画在首次运行时无效

Question

我有一个包含项目列表的活动,当您点击某个项目时,我希望该项目的播放控件从屏幕底部向上滑动并变为可见.我为幻灯片定义了一个动画集并且滑出了它们并且它们起作用.我在我的活动中设置了我的animationListener,并在动画上点击了一个项目.我的问题是,第一次运行应用程序时,当我单击某个项目时,会执行onClick回调,但动画不会发生.我第二次点击,动画中的幻灯片发生了,但没有滑出.第三次及以后,它按预期工作.这是我的动画集.

vm_slide_in.xml

    <?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" 
           android:fillAfter="true">
    <translate
        android:fromYDelta="800"
        android:toYDelta="0"
        android:duration="600" />
</set>

vm_slide_out.xml

    <?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" 
           android:fillAfter="true">
    <translate
        android:fromYDelta="0"
        android:toYDelta="800"
        android:duration="600" />
</set>

这是我的活动布局

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    style="@style/AppBG">
    <RelativeLayout 
        style="@style/LogoBar" 
        android:id="@+id/logo_bar"      
        android:layout_alignParentTop="true">
        <include layout="@layout/logobar"></include>
    </RelativeLayout>
    <RelativeLayout 
        style="@style/TitleBar" 
        android:id="@+id/title_bar"     
        android:layout_below="@+id/logo_bar">
        <include layout="@layout/titlebar"></include>"
        <Button style="@style/TitleBarButton"
            android:id="@+id/vm_speaker_btn"
            android:text="@string/vm_speaker_btn_label" 
            android:layout_alignParentLeft="true"
            android:layout_margin="4dp">
        </Button>
        <Button style="@style/TitleBarButton"
            android:id="@+id/vm_edit_btn"
            android:text="@string/vm_edit_btn_label" 
            android:layout_alignParentRight="true"
            android:layout_margin="4dp">
        </Button>
    </RelativeLayout>
    <ListView
        android:id="@+id/@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/title_bar"/>
    <RelativeLayout
        android:id="@+id/vm_control_panel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/footer"
        android:visibility="gone">
        <include layout="@layout/vm_control"/>
    </RelativeLayout>
    <RelativeLayout
        android:id="@+id/footer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true">
        <include layout="@layout/taskbar"/>
    </RelativeLayout>
</RelativeLayout>

这是包含控件的布局

    <?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android">
    <RelativeLayout 
        android:id="@+id/vm_control"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@color/dark_grey">
        <TextView
            android:id="@+id/vm_ctl_branding"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="5dp"
            android:text="@string/branding"
            android:textColor="@color/white">
        </TextView>
        <TextView style="@style/TimeMark"
            android:id="@+id/vm_timestamp"
            android:layout_toLeftOf="@+id/vm_progress"
            android:layout_below="@+id/vm_ctl_branding"
            android:layout_marginRight="3dp"
            android:text="0:00">
        </TextView>
        <SeekBar
            android:id="@+id/vm_progress"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:layout_below="@+id/vm_ctl_branding"
            android:layout_centerHorizontal="true">
        </SeekBar>
        <TextView style="@style/TimeMark"
            android:id="@+id/vm_timeleft"
            android:layout_toRightOf="@+id/vm_progress"
            android:layout_below="@+id/vm_ctl_branding"
            android:layout_marginLeft="3dp"
            android:text="-0:00">
        </TextView>
        <LinearLayout
            android:id="@+id/vm_action_button_layout"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@+id/vm_timestamp"
            android:layout_alignRight="@+id/vm_timeleft"
            android:orientation="horizontal"
            android:layout_below="@+id/vm_progress">
            <TextView style="@style/Vm_Action_Button"
                android:background="@drawable/vm_action_btn_call"
                android:id="@+id/vm_callback_btn"
                android:layout_marginRight="5dp"
                android:text="@string/vm_action_btn_callback">
            </TextView>
            <TextView style="@style/Vm_Action_Button"
                android:background="@drawable/vm_action_btn_delete"
                android:id="@+id/vm_delete_btn"
                android:layout_marginLeft="5dp"
                android:text="@string/vm_action_btn_delete">
            </TextView>
        </LinearLayout>
    </RelativeLayout>
</merge>

从我的onCreate方法...

// Handle list item selections
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        final Voicemail vmItem = (Voicemail) vmla.getItem(position);
        Toast.makeText(ctx, "Name: " + vmItem.getCallerName() + " Position: " + position, Toast.LENGTH_SHORT)
                .show();
        vVm_controls.startAnimation(mSlideIn);
    }
});

我的动画回调......

@Override
public void onAnimationStart(Animation animation) {
    vm_controls_in = !vm_controls_in;
    if (vm_controls_in) {
        vVm_controls.setVisibility(View.GONE);
    } else {
        vVm_controls.setVisibility(View.VISIBLE);
        // vVm_controls.bringToFront();
    }
}

@Override
public void onAnimationEnd(Animation animation) {
    if (!vm_controls_in) {
        try {
            Thread.sleep(1000);
            vVm_controls.startAnimation(mSlideOut);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

@Override
public void onAnimationRepeat(Animation animation) {
    // TODO Auto-generated method stub

}

Answer 1

正如您所发现的,问题在于可见性.当视图最初在xml文件中设置为已消失时,Android将不会呈现布局,直到可见性更改为可见或不可见.如果您尝试在尚未渲染的视图上设置动画,则动画将在没有布局的视图上进行.动画完成后,它将渲染它并突然显示视图而不显示动画.它随后会工作,因为即使设置为已经过去,视图也会有布局.

关键是将可见性设置为不可见而不是在xml文件中消失,以便将其呈现为隐藏状态.当动画第一次出现时会出现动画并按预期移动.

Answer 2

当然在发布这个问题后不到20分钟,我就发现了我的问题.因为我将布局的可见性设置为"GONE",所以当我尝试在其上启动动画时,它没有第一次触发.不确定为什么它会在第二次及以后的时间进行,但如果我在开始动画之前将可见性设置为"VISIBLE",则可以解决问题.这是我改变它的代码......

// Handle list item selections
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        final Voicemail vmItem = (Voicemail) vmla.getItem(position);
        Toast.makeText(ctx, "Name: " + vmItem.getCallerName() + " Position: " + position, Toast.LENGTH_SHORT)
                .show();
        vVm_controls.setVisibility(View.VISIBLE);
        vVm_controls.startAnimation(mSlideIn);
    }
});

Answer 3

我不知道它是否仍然是最新的但是,这是可见性的问题.因此,我将xml文件中的可见性设置为不可见,并在初始化视图的位置调用:

view.post(new Runnable() {
    @Override
    public void run() {
        view.animate().translationY(view.getHeight());
    }
};

现在来电

view.animate().translationY(0).setListener(new AnimatorListenerAdapter() {
    @Override
    public void onAnimationStart(Animator animation) {
        super.onAnimationStart(animation);
        view.setVisibility(View.VISIBLE);
    }
}

也是第一次工作.