Android float Activity 与滑动关闭

Question

最新的 Facebook 安卓应用有一个非常漂亮的 float 评论窗口。在那里，用户可以关闭向上或向下滑动的窗口，使其真正易于使用。

我想在我的应用中实现类似的行为，但我不知道该怎么做。任何关于如何做的想法或线索将不胜感激。

Facebook 应用的屏幕截图
(抱歉，我截取屏幕截图的 Facebook 应用程序是日文的)

Answer 1

我编写了一些与这种关闭/调整大小行为相匹配的代码，我不知道这是否可行，但我的代码基于 Activity 类。我要做的第一件事是创建一个 Activity 并给它Transluscent主题以获得具有透明背景的 Activity 。

在我的 manifest.xml 中:

<activity
    android:name=".PopupActivity"
    android:label="@string/title_activity_popup"
    <!-- Use Translucent theme to get transparent activity background 
     and NoTitleBar to avoid super old style title bar ;) -->
    android:theme="@android:style/Theme.Translucent.NoTitleBar">
</activity>

然后我创建一个简单的布局文件，其中包含一个 TextView (对应于 Facebook 聊天部分)和一个 View (对应于 Facebook“写你的消息”/“发送笑脸”选项​​卡)

我的布局/activity_popup.xml:

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/base_popup_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="8dp"
    android:background="@android:color/darker_gray"
    android:layout_marginBottom="124dp">

    <TextView
        android:text="@string/hello_world"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:background="@android:color/black"/>

    <View
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:layout_alignParentBottom="true"
        android:background="@android:color/holo_blue_dark"/>

</RelativeLayout>

最后我在 PopupActivity 类中处理触摸和移动事件，我使用 onTouchListener在 onTouch 方法中提供回调。

PopupActivity

public class PopupActivity extends Activity implements View.OnTouchListener{

    private RelativeLayout baseLayout;

    private int previousFingerPosition = 0;
    private int baseLayoutPosition = 0;
    private int defaultViewHeight;

    private boolean isClosing = false;
    private boolean isScrollingUp = false;
    private boolean isScrollingDown = false;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_popup);
        baseLayout = (RelativeLayout) findViewById(R.id.base_popup_layout);
        baseLayout.setOnTouchListener(this);
    }


    public boolean onTouch(View view, MotionEvent event) {

        // Get finger position on screen
        final int Y = (int) event.getRawY();

        // Switch on motion event type
        switch (event.getAction() & MotionEvent.ACTION_MASK) {

            case MotionEvent.ACTION_DOWN:
                // save default base layout height
                defaultViewHeight = baseLayout.getHeight();

                // Init finger and view position
                previousFingerPosition = Y;
                baseLayoutPosition = (int) baseLayout.getY();
                break;

            case MotionEvent.ACTION_UP:
                // If user was doing a scroll up
                if(isScrollingUp){
                    // Reset baselayout position
                    baseLayout.setY(0);
                    // We are not in scrolling up mode anymore
                    isScrollingUp = false;
                }

                // If user was doing a scroll down
                if(isScrollingDown){
                    // Reset baselayout position
                    baseLayout.setY(0);
                    // Reset base layout size
                    baseLayout.getLayoutParams().height = defaultViewHeight;
                    baseLayout.requestLayout();
                    // We are not in scrolling down mode anymore
                    isScrollingDown = false;
                }
                break;
            case MotionEvent.ACTION_MOVE:
                if(!isClosing){
                    int currentYPosition = (int) baseLayout.getY();

                    // If we scroll up
                    if(previousFingerPosition >Y){
                        // First time android rise an event for "up" move
                        if(!isScrollingUp){
                            isScrollingUp = true;
                        }

                    // Has user scroll down before -> view is smaller than it's default size -> resize it instead of change it position
                    if(baseLayout.getHeight()<defaultViewHeight){
                        baseLayout.getLayoutParams().height = baseLayout.getHeight() - (Y - previousFingerPosition);
                        baseLayout.requestLayout();
                    }
                    else {
                        // Has user scroll enough to "auto close" popup ?
                        if ((baseLayoutPosition - currentYPosition) > defaultViewHeight / 4) {
                            closeUpAndDismissDialog(currentYPosition);
                            return true;
                        }

                        //
                    }
                    baseLayout.setY(baseLayout.getY() + (Y - previousFingerPosition));

                }
                // If we scroll down
                else{

                    // First time android rise an event for "down" move
                    if(!isScrollingDown){
                        isScrollingDown = true;
                    }

                    // Has user scroll enough to "auto close" popup ?
                    if (Math.abs(baseLayoutPosition - currentYPosition) > defaultViewHeight / 2)
                    {
                        closeDownAndDismissDialog(currentYPosition);
                        return true;
                    }

                    // Change base layout size and position (must change position because view anchor is top left corner)
                    baseLayout.setY(baseLayout.getY() + (Y - previousFingerPosition));
                    baseLayout.getLayoutParams().height = baseLayout.getHeight() - (Y - previousFingerPosition);
                    baseLayout.requestLayout();
                }

                // Update position
                previousFingerPosition = Y;
            }
            break;
        }
        return true;
    }
}

当用户滚动到足以关闭弹出窗口(即动画和完成 Activity )时，会调用两个小方法:

public void closeUpAndDismissDialog(int currentPosition){
    isClosing = true;
    ObjectAnimator positionAnimator = ObjectAnimator.ofFloat(baseLayout, "y", currentPosition, -baseLayout.getHeight());
    positionAnimator.setDuration(300);
    positionAnimator.addListener(new Animator.AnimatorListener()
    {
        . . .
        @Override
        public void onAnimationEnd(Animator animator)
        {
            finish();
        }
        . . .
    });
    positionAnimator.start();
}

public void closeDownAndDismissDialog(int currentPosition){
    isClosing = true;
    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);
    int screenHeight = size.y;
    ObjectAnimator positionAnimator = ObjectAnimator.ofFloat(baseLayout, "y", currentPosition, screenHeight+baseLayout.getHeight());
    positionAnimator.setDuration(300);
    positionAnimator.addListener(new Animator.AnimatorListener()
     {
        . . .
        @Override
        public void onAnimationEnd(Animator animator)
        {
            finish();
        }
        . . .
    });
    positionAnimator.start();
}

使用所有这些代码，您应该能够启动全局匹配 Facebook 弹出行为的 PopupActivity。这只是一个草稿类，还有很多工作要做:添加动画、处理关闭参数等等......

截图: