最新的 Facebook 安卓应用有一个非常漂亮的浮动评论窗口。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 应用程序的屏幕截图
（抱歉，我截取屏幕截图的 Facebook 应用程序是日文的）
【问题讨论】：
标签： android android-layout android-activity
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活动并给它Transluscenttheme 以获得具有透明背景的活动。
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，其中包含一个文本视图（对应于 Facebook 聊天部分）和一个视图（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（即动画和完成活动）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 弹出窗口行为的 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：
【讨论】：
我认为您可以使用 appcompat 库中的 BottomSheetDialogFragment 组件。查看这篇文章以获取信息： https://medium.com/@nullthemall/new-bottomsheet-caab21aff19b#.gpu1l516z
您还可以从以下网站获取有用信息 documentaion.
【讨论】：
好吧，OP 标题要求浮动活动，但 OP 内容正在寻找类似于 facebook 评论窗口的 浮动评论窗口。
因此，这将由 DialogFragment 实现，它为我们提供了在您向上或向下滑动时自动将对话框弹回其原始状态/窗口大小的行为。当对话框被滑动一点（精确地滑动小于原始布局大小的一半的距离）时，这种行为会保持。
剩下的事情是如果它的大小小于原始窗口大小的一半，它就会关闭这个对话框；换句话说，如果它的滑动大于原始布局大小的一半。这部分是通过更改对话框窗口根布局的唯一Y 位置来从接受的答案调整的，并且不更改窗口的大小，因为这提供了奇怪的调整大小行为。
首先创建此样式以使对话窗口具有透明背景：
<style name="NoBackgroundDialogTheme" parent="Theme.AppCompat.Light.Dialog">
<item name="android:windowBackground">@null</item>
</style>
此样式将通过覆盖 getTheme() 方法应用于 DialogFragment。
这是自定义的DialogFragment：
class MyDialogFragment : DialogFragment(), View.OnTouchListener {
private var rootLayoutY: Int = 0
private val rootLayout by lazy {
requireView().findViewById<ConstraintLayout>(R.id.dialog_root)
}
private var oldY = 0
private var baseLayoutPosition = 0
private var defaultViewHeight = 0
private var isScrollingUp = false
private var isScrollingDown = false
override fun getTheme(): Int {
return R.style.NoBackgroundDialogTheme
}
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
val view: View = inflater.inflate(
R.layout.fragment_dialog_facebook_comment, container,
false
)
view.setBackgroundResource(R.drawable.rounded_background)
return view
}
override fun onStart() {
super.onStart()
// Making the dialog full screen
dialog?.window?.setLayout(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.MATCH_PARENT
)
}
@SuppressLint("ClickableViewAccessibility")
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
rootLayout.setOnTouchListener(this)
rootLayout.viewTreeObserver.addOnGlobalLayoutListener(object :
OnGlobalLayoutListener {
override fun onGlobalLayout() {
rootLayout.viewTreeObserver
.removeOnGlobalLayoutListener(this)
// save default base layout height
defaultViewHeight = rootLayout.height
}
})
}
@SuppressLint("ClickableViewAccessibility")
override fun onTouch(v: View?, event: MotionEvent?): Boolean {
// Get finger position on screen
val y = event!!.rawY.toInt()
// Switch on motion event type
when (event.action and MotionEvent.ACTION_MASK) {
MotionEvent.ACTION_DOWN -> {
// Init finger and view position
oldY = y
baseLayoutPosition = rootLayout.y.toInt()
}
MotionEvent.ACTION_UP -> {
if (rootLayoutY >= defaultViewHeight / 2) {
dismiss()
return true
}
// If user was doing a scroll up
if (isScrollingUp) {
// Reset baselayout position
rootLayout.y = 0f
// We are not in scrolling up mode anymore
isScrollingUp = false
}
// If user was doing a scroll down
if (isScrollingDown) {
// Reset baselayout position
rootLayout.y = 0f
// Reset base layout size
rootLayout.layoutParams.height = defaultViewHeight
rootLayout.requestLayout()
// We are not in scrolling down mode anymore
isScrollingDown = false
}
}
MotionEvent.ACTION_MOVE -> {
rootLayoutY = abs(rootLayout.y.toInt())
// Change base layout size and position (must change position because view anchor is top left corner)
rootLayout.y = rootLayout.y + (y - oldY)
if (oldY > y) { // scrolling up
if (!isScrollingUp) isScrollingUp = true
} else { // Scrolling down
if (!isScrollingDown) isScrollingDown = true
}
// Update y position
oldY = y
}
}
return true
}
}
在我的例子中，对话框的根布局是ConstraintLayout。
【讨论】：