Android 实现下拉界面一种方式

需要是按的效果
从屏幕顶端下拉出来一个界面跟随手势滑动

效果如下
image

先看一下实现之后的window 层级

$ dumpsys window windows
Window #0 Window{2710e08 u0 SystemUI_smallPanel}:
mDisplayId=0 rootTaskId=1 mSession=Session{4739268 1310:1000} mClient=android.os.BinderProxy@69125fa
mOwnerUid=1000 showForAllUsers=true package=com.android.systemui appop=NONE
mAttrs={(0,0)(1440x35) gr=TOP LEFT CENTER sim={adjust=pan} ty=2100 fmt=TRANSLUCENT
fl=NOT_FOCUSABLE LAYOUT_IN_SCREEN LAYOUT_NO_LIMITS FULLSCREEN HARDWARE_ACCELERATED
pfl=FIT_INSETS_CONTROLLED
bhv=SHOW_TRANSIENT_BARS_BY_SWIPE
fitTypes=STATUS_BARS NAVIGATION_BARS CAPTION_BAR
fitSides=}

可以看到有一个高度为35的view,放置在屏幕的顶部,这个就是当前用来响应下拉的一个入口,相对应的参数配置如下

@RequiresApi(api = Build.VERSION_CODES.R)
protected WindowManager.LayoutParams createSmallPanelWindowParams(Context context, Display display, int w, int h, int gravity) {
WindowManager.LayoutParams params = new WindowManager.LayoutParams(
WindowManager.LayoutParams.MATCH_PARENT,
WindowManager.LayoutParams.WRAP_CONTENT,
GlobalConstants.STATUS_PANEL_WINDOW_TYPE,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_FULLSCREEN
| WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS
| WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
& ~WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH,
PixelFormat.TRANSLUCENT);
params.packageName = context.getPackageName();
params.gravity = gravity;
params.width = w;
params.height = h;
params.setFitInsetsSides(0);
params.setTitle("SystemUI_smallPanel");
return params;
}

然后对该view 监听触摸事件 onTouch(View v, MotionEvent event),把拿到的 event 抛出给到真正需要跟随下拉实现的view 来做对应事件处理

接下来看真正下拉显示的view,也是一开始就已经添加在了window 里面

Window #1 Window{390618f u0 SystemUI_Container}:
mDisplayId=0 rootTaskId=1 mSession=Session{4739268 1310:1000} mClient=android.os.BinderProxy@6b08669
mOwnerUid=1000 showForAllUsers=true package=com.android.systemui appop=NONE
mAttrs={(0,0)(1440x1920) gr=START CENTER_HORIZONTAL sim={adjust=pan} ty=2100 fmt=TRANSLUCENT
fl=DIM_BEHIND NOT_FOCUSABLE LAYOUT_IN_SCREEN LAYOUT_NO_LIMITS FULLSCREEN HARDWARE_ACCELERATED
pfl=FIT_INSETS_CONTROLLED
bhv=SHOW_TRANSIENT_BARS_BY_SWIPE
fitTypes=STATUS_BARS NAVIGATION_BARS CAPTION_BAR
fitSides=}

然后再这个view 中去处理 上一个传过来的 MotionEvent

public void postOpenTouch(MotionEvent event) {
// 对event 各个状态 适配当前view 的滑动就可完成此效果
}

方案小结

能达到系统需要的效果,弊端在于多添加了一个view到window上,有一个MotionEvent传递的过程,需要把这个步骤处理好,一面出现下拉无响应的情况

其他实现思路
若是能拿到系统的后门InputManager,直接监听系统input 事件来实现,就能避免以上方案的弊端
大概实现落实如下:

private InputManager mInputManager;
private InputMonitor mInputMonitor;
public void init() {
mInputManager = (InputManager) context.getSystemService(Context.INPUT_SERVICE);
mInputMonitor = mInputManager.monitorGestureInput(
"gesture_monitor",
Display.DEFAULT_DISPLAY
);
MyMonitor m = new MyMonitor(context, Display.DEFAULT_DISPLAY);
mPointerEventDispatcher = new PointerEventDispatcher(mInputMonitor.getInputChannel());
mPointerEventDispatcher.registerInputEventListener(m);
}

定义的 MyMonitor

public class MyMonitor implements WindowManagerPolicyConstants.PointerEventListener{
@Override
public void onPointerEvent(MotionEvent motionEvent) {
// do sth
}
}
public class PointerEventDispatcher extends InputEventReceiver {
private static final String TAG = "PointerEventDispatcher";
private final ArrayList<PointerEventListener> mListeners = new ArrayList<>();
private PointerEventListener[] mListenersArray = new PointerEventListener[0];
public PointerEventDispatcher(InputChannel inputChannel) {
super(inputChannel, Looper.getMainLooper());
Log.d(TAG, "PointerEventDispatcher:");
}
@Override
public void onInputEvent(InputEvent event) {
try {
if (event instanceof MotionEvent && (event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) {
final MotionEvent motionEvent = (MotionEvent) event;
PointerEventListener[] listeners;
synchronized (mListeners) {
if (mListenersArray == null) {
mListenersArray = new PointerEventListener[mListeners.size()];
mListeners.toArray(mListenersArray);
}
listeners = mListenersArray;
}
for (int i = 0; i < listeners.length; ++i) {
listeners[i].onPointerEvent(motionEvent);
}
}
} finally {
finishInputEvent(event, false);
}
}
/**
* Add the specified listener to the list.
*
* @param listener The listener to add.
*/
public void registerInputEventListener(PointerEventListener listener) {
Log.d(TAG, "registerInputEventListener: ");
synchronized (mListeners) {
if (mListeners.contains(listener)) {
Log.w(TAG, "registerInputEventListener: trying to register" + listener + " twice.");
return;
}
Log.d(TAG, "register " + listener);
mListeners.add(listener);
mListenersArray = null;
}
}
/**
* Remove the specified listener from the list.
*
* @param listener The listener to remove.
*/
public void unregisterInputEventListener(PointerEventListener listener) {
synchronized (mListeners) {
if (!mListeners.contains(listener)) {
Log.w(TAG, "unregisterInputEventListener: " + listener + " not registered.");
return;
}
Log.d(TAG, "unRegister " + listener);
// 直接清空
mListeners.clear();
mListenersArray = null;
}
}
/**
* Dispose the associated input channel and clean up the listeners.
*/
@Override
public void dispose() {
super.dispose();
synchronized (mListeners) {
mListeners.clear();
mListenersArray = null;
}
}
}

拿到的 MotionEvent ,就能实现需求所述功能

posted @   阿丟啊  阅读(634)  评论(1编辑  收藏  举报
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