Jus*_*tin 6 android swipe onfling gesturedetector
我编写了一些代码来实现Gallery小部件的垂直滑动.它在Android 1.5和1.6中运行良好但在Android 2.2中不起作用(我还没有尝试使用2.1).
public class SwipeUpDetector extends SimpleOnGestureListener
implements OnTouchListener
{
private GestureDetector m_detector;
public SwipeUpDetector()
{
m_detector = new GestureDetector(m_context, this);
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
{
if (Math.abs(e1.getX() - e2.getX()) < s_swipeMaxOffPath &&
e1.getY() - e2.getY() >= s_swipeMinDistance &&
Math.abs(velocityY) >= s_swipeMinVelocity)
{
int pos = m_gallery.pointToPosition((int)e1.getX(), (int)e2.getY());
startAnimation(pos);
return true;
}
return false;
}
@Override
public boolean onTouch(View v, MotionEvent event)
{
return m_detector == null ? false : m_detector.onTouchEvent(event);
}
}
为了能够让我的画廊检测到onFling我有以下内容:
m_gallery.setOnTouchListener(new SwipeUpDetector());
在Android 1.5和1.6中,这非常有效.在Android 2.2中,永远不会调用onFling().在浏览Google和StackOverflow时,我发现一个可能的解决方案是实现onDown()并返回true.
但是,我也在听单击,并在此库中设置了上下文菜单监听器.当我实现onDown()并返回true时,我确实让滑动工作.但是,当我这样做时,上下文菜单不会显示长按,单击也不起作用...单击图库中的项目会导致图库跳转,我没有收到任何反馈单击库中的项目.它只是立即使该项目成为所选项目并将其移动到中心.
我查看了1.6,2.1和2.2之间的API差异报告,并没有看到可能导致其破坏的重要性.
我究竟做错了什么？
知道图库嵌套在几个布局中可能也会有所帮助,如下所示(这不是一个完整的布局......它只是为了显示这个图库所在的层次结构):
<ScrollView>
<LinearLayout>
<RelativeLayout> <!-- This relative layout is a custom one that I subclassed -->
<Gallery />
</RelativeLayout>
</LinearLayout>
</ScrollView>
以下是请求的布局......为了可重用性,有两个布局.这是第一个,它是主要活动的布局:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:myns="http://com.magouyaware/appswipe"
android:id="@+id/main_layout_id"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center_horizontal"
android:scrollbarAlwaysDrawVerticalTrack="false"
>
<LinearLayout
android:id="@+id/appdocks_layout_id"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="10dp"
android:layout_gravity="center"
android:orientation="vertical"
android:gravity="center"
android:background="@null"
>
<com.magouyaware.appswipe.TitledGallery
android:id="@+id/running_gallery_layout_id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:visibility="gone"
myns:gallery_title="@string/running_title"
/>
<com.magouyaware.appswipe.TitledGallery
android:id="@+id/recent_gallery_layout_id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:visibility="gone"
myns:gallery_title="@string/recent_title"
/>
<com.magouyaware.appswipe.TitledGallery
android:id="@+id/favs_gallery_layout_id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:visibility="gone"
myns:gallery_title="@string/favs_title"
/>
<com.magouyaware.appswipe.TitledGallery
android:id="@+id/service_gallery_layout_id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:visibility="gone"
myns:gallery_title="@string/service_title"
/>
<com.magouyaware.appswipe.TitledGallery
android:id="@+id/process_gallery_layout_id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:visibility="gone"
myns:gallery_title="@string/process_title"
/>
<include
android:id="@+id/indeterminate_progress_layout_id"
layout="@layout/indeterminate_progress_layout"
/>
</LinearLayout>
</ScrollView>
这里是com.magouyaware.appswipe.TitledGallery的布局文件......这只是一个RelativeLayout子类,用于将多个视图作为代码中的单个项控制并具有可重用性:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/titled_gallery_main_layout_id"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_vertical"
android:layout_gravity="center_vertical"
android:background="@null"
>
<LinearLayout
android:id="@+id/titled_gallery_expansion_layout_id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:focusable="true"
android:clickable="true"
android:gravity="center_vertical"
>
<ImageView
android:id="@+id/titled_gallery_expansion_image_id"
android:layout_width="20dp"
android:layout_height="20dp"
android:duplicateParentState="true"
android:clickable="false"
/>
<TextView
style="@style/TitleText"
android:id="@+id/titled_gallery_title_id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="left"
android:paddingLeft="1sp"
android:paddingRight="10sp"
android:textColor="@drawable/titled_gallery_text_color_selector"
android:duplicateParentState="true"
android:clickable="false"
/>
</LinearLayout>
<Gallery
android:id="@+id/titled_gallery_id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@id/titled_gallery_expansion_layout_id"
android:layout_alignWithParentIfMissing="true"
android:spacing="5sp"
android:clipChildren="false"
android:clipToPadding="false"
android:unselectedAlpha=".5"
android:focusable="false"
/>
<TextView
style="@style/SubTitleText"
android:id="@+id/titled_gallery_current_text_id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@id/titled_gallery_id"
android:layout_alignWithParentIfMissing="true"
android:gravity="center_horizontal"
/>
</RelativeLayout>
通过在SimpleOnGestureListener 的实现中实现onSingleTapConfirmed、onDoubleTap和onLongPress （同时从onDown返回true ） ，我还能够接收单击/双击和长按。
关于为什么我们应该覆盖onDown方法。我认为这与问题#8233有关。据报道一年前针对2.1版本。由于到目前为止只有 10 人加星，我猜它不会在不久的将来得到修复。
更新
事实证明，该问题是由ScrollView和的组合Gallery和使用引起的OnTouchListener。Gallery它本身实现OnGestureListener并封装了当我们设置OnTouchListenerGestureDetector时禁用的功能，有时会导致奇怪的画廊行为。另一方面，如果我们只是对 Gallery 组件进行子类化并在其 onLongPress/onFling 方法中执行长按/滑动检测，则父 ScrollView 将拦截垂直移动事件，从而防止 onFling 调用此类事件。解决方案是覆盖并调用画廊父级。 Gallery.dispatchTouchEventrequestDisallowInterceptTouchEvent(true)
总结一下：如果您想检测 Gallery 的滑动（长按、双击等）（并可能将其放置在 ScrollView 内），请使用下面提供的自定义组件，而不是 GestureDetector/OnTouchListener。
public class FlingGallery extends android.widget.Gallery implements OnDoubleTapListener {
private static final int SWIPE_MIN_VELOCITY = 30; // 30dp, set to the desired value
private static final int SWIPE_MIN_DISTANCE = 50; // 50dp, set to the desired value
private static final int SWIPE_MAX_OFF_PATH = 40; // 40dp, set to the desired value
private final float mSwipeMinDistance;
private final float mSwipeMaxOffPath;
private final float mSwipeMinVelocity;
public FlingGallery(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
float density = context.getResources().getDisplayMetrics().density;
this.mSwipeMinDistance = density * SWIPE_MIN_DISTANCE;
this.mSwipeMaxOffPath = density * SWIPE_MAX_OFF_PATH;
this.mSwipeMinVelocity = density * SWIPE_MIN_VELOCITY;
}
public FlingGallery(Context context, AttributeSet attrs) {
this(context, attrs, android.R.attr.galleryStyle);
}
public FlingGallery(Context context) {
this(context, null);
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
final ViewParent parent;
if (ev.getAction() == MotionEvent.ACTION_MOVE && (parent = getParent()) != null) {
parent.requestDisallowInterceptTouchEvent(true); // this will be passed up to the root view, i.e. ScrollView in our case
}
return super.dispatchTouchEvent(ev);
}
@Override
public boolean onDoubleTap(MotionEvent e) {
// Your double-tap handler...
return true;
}
@Override
public boolean onDoubleTapEvent(MotionEvent e) {
return false;
}
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
// Your single-tap handler...
return true;
}
@Override
public void onLongPress(MotionEvent event) {
// Your long-press handler...
super.onLongPress(event);
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if (e1 == null) {
return super.onFling(e1, e2, velocityX, velocityY);
}
float dx = e2.getX() - e1.getX();
float dy = e2.getY() - e1.getY();
if (abs(dx) < mSwipeMaxOffPath && abs(velocityY) > mSwipeMinVelocity && abs(dy) > mSwipeMinDistance) {
if (dy > 0) {
// Your from-top-to-bottom handler...
} else {
// Your from-bottom-to-top handler...
}
} else if (abs(dy) < mSwipeMaxOffPath && abs(velocityX) > mSwipeMinVelocity && abs(dx) > mSwipeMinDistance) {
if (dx > 0) {
// Your from-left-to-right handler...
} else {
// Your from-right-to-left handler...
}
}
return super.onFling(e1, e2, velocityX, velocityY);
}
}