我从SPen库中借用了ToolHoverPopup类中的一些代码,我也为这个特殊的弹出窗口进行了自定义,以便在实际悬停发生之前不会创建或膨胀任何内容,这样我们就不会消耗资源来在列表中启用这样的预览.

我们需要将预览附加到Window上,因此我们必须管理通常由PopupWindow完成的所有底层定位工作,所以我完全删除了对PopupWindow的依赖,现在我的HoverPreview类完全正常工作和管理所有作业,它还能够以毫秒为单位确定悬停检测延迟.

截图(SurfaceView已创建)

用法:(由于布局包含SurfaceView并且是资源密集型的,我手动触发onHover事件,以便仅在执行真实悬停时才执行真实表面创建.同样,在此之前,我不会在需要之前创建任何HoverPreview对象)

        thumbnailImageView.setOnHoverListener(new View.OnHoverListener() {
            @Override
            public boolean onHover(View view,MotionEvent motionEvent) {
                HoverPreview hoverPreview;
                if (thumbnailImageView.getTag() == null) {
                    hoverPreview = new HoverPreview(context,getActivity().getWindow(),0);
                    hoverPreview.setHoverDetectTime(1000);
                    thumbnailImageView.setTag(hoverPreview);
                } else
                    hoverPreview = (HoverPreview) thumbnailImageView.getTag();
                hoverPreview.onHover(null,motionEvent);
                if (motionEvent.getAction() == MotionEvent.ACTION_HOVER_EXIT)
                    thumbnailImageView.setTag(null);
                return true;
            }
        });

HoverPreview：

public class HoverPreview extends LinearLayout implements View.OnHoverListener,SurfaceHolder.Callback {
    private static final int MSG_SHOW_POPUP = 1;
    private static final int MSG_DISMISS_POPUP = 2;
    private static final int HOVER_DETECT_TIME_MS = 300;
    private static final int POPUP_TIMEOUT_MS = 60 * 1000;
    protected int mHoverDetectTimeMS;
    private static final String TAG = "HoverPreview";
    private SurfaceHolder mHolder = null;
    String videoPath;
    int position;
    private boolean IsMediaPlayerReady = false;
    private MediaPlayer mMediaPlayer;
    private SurfaceView mSurfaceView;
    Context context;
    private HoverPopupHandler mHandler;
    Window window;
    public HoverPreview(Context context,Window window,int position) {
        super(context);
        this.mHoverDetectTimeMS = HOVER_DETECT_TIME_MS;
        this.videoPath = videoPath;
        this.position = position;
        this.window = window;
        setupLayout(context);
    }
    private void setupLayout(Context context) {
        this.context = context;
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        rootView = inflater.inflate(R.layout.media_browser_hover,this);
        mSurfaceView = (SurfaceView) findViewById(R.id.media_browser_hoverSurfaceView);
    }
    View rootView;
    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
    }
    @Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        Log.d(TAG,"HoverSurface created");
        final Surface surface = surfaceHolder.getSurface();
        if (surface == null) return;
        if (!surface.isValid()) return;
        mHolder = surfaceHolder;
        mMediaPlayer = new MediaPlayer();
        try {
            mMediaPlayer.setDataSource(videoPath);
        } catch (IOException e) {
            e.printStackTrace();
            return;
        }
        mMediaPlayer.setDisplay(mHolder);
        mMediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
            @Override
            public void onPrepared(MediaPlayer mediaPlayer) {
                Log.d(TAG,"MediaPlayer preview is prepared");
                IsMediaPlayerReady = true;
                int videoWidth = mMediaPlayer.getVideoWidth();
                int videoHeight = mMediaPlayer.getVideoHeight();
                Point size = new Point();
                int screenHeight = 0;
                int screenWidth = 0;
                Display display = getDisplay();
                display.getSize(size);
                screenWidth = size.x - (350 + 30); // margin + padding
                screenHeight = size.y;
                FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) mSurfaceView.getLayoutParams();
                lp.width = screenWidth;
                lp.height = (int) (((float) videoHeight / (float) videoWidth) * (float) screenWidth);
                mSurfaceView.setLayoutParams(lp);
                if (mMediaPlayer != null && IsMediaPlayerReady) {
                    if (position > 0)
                        mMediaPlayer.seekTo(position);
                    mMediaPlayer.start();
                    findViewById(R.id.media_browser_hoverRootFrameLayout).setVisibility(VISIBLE);
                }
            }
        });
        Log.d(TAG,"HoverSurface destroyed");
        try {
            if (mMediaPlayer != null) {
                mMediaPlayer.stop();
                mMediaPlayer.release();
            }
        } catch (Exception e) {
        }
    }
    @Override
    public boolean onHover(View view,"ACTION_HOVER_ENTER");
                show(); // checks the timing
            } else if (motionEvent.getAction() == MotionEvent.ACTION_HOVER_EXIT) {
                Log.d(TAG,"ACTION_HOVER_EXIT");
                dismiss();
            }
        } catch (Exception e) {
            Log.e(TAG,e.getMessage() + Utils.toString(e.getStackTrace()));
        }
        return false;
    }
    /**
     * Sets the time that detecting hovering.
     *
     * @param ms The time,milliseconds
     */
    public void setHoverDetectTime(int ms) {
        mHoverDetectTimeMS = ms;
    }
    public void dismiss() {
        dismissPopup();
    }
    private void dismissPopup() {
        // remove pending message and dismiss popup
        getMyHandler().removeMessages(MSG_SHOW_POPUP);
        getMyHandler().removeMessages(MSG_DISMISS_POPUP);
        try {
            if (mMediaPlayer != null) {
                mMediaPlayer.stop();
                mMediaPlayer.release();
            }
        } catch (Exception e) {
        }
        if (getParent() != null)
            ((ViewGroup) getParent()).removeView(this);
    }
    private Handler getMyHandler() {
        if (mHandler == null)
            mHandler = new HoverPopupHandler();
        return mHandler;
    }
    public void show() {
        // send message to show.
        if (getMyHandler().hasMessages(MSG_SHOW_POPUP)) {
            return;
            // getHandler().removeMessages(MSG_SHOW_POPUP);
        }
        getMyHandler().sendEmptyMessageDelayed(MSG_SHOW_POPUP,mHoverDetectTimeMS);
    }
    private void showPopup() {
        if (getParent() == null) {
            final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                    WindowManager.LayoutParams.MATCH_PARENT,WindowManager.LayoutParams.MATCH_PARENT,WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,PixelFormat.TRANSLUCENT);
            params.gravity = Gravity.CENTER_VERTICAL;
            params.x = 350;
            window.addContentView(this,params);
        }
        mHolder = mSurfaceView.getHolder();
        if (mHolder != null) {
            mHolder.addCallback(this);
        }
    }
    ;
    private class HoverPopupHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
//            if (DEBUG)
//                android.util.Log.e(TAG,"handleMessage : " + ((msg.what == MSG_SHOW_POPUP) ? "SHOW" : "DISMISS"));
            switch (msg.what) {
                case MSG_SHOW_POPUP:
                    showPopup();
                    sendEmptyMessageDelayed(MSG_DISMISS_POPUP,POPUP_TIMEOUT_MS);
                    break;
                case MSG_DISMISS_POPUP:
                    dismissPopup();
                    break;
            }
        }
    }
}