1. 功能

通過監聽手指擡起的事件，記錄對應時間戳，通過最近2次手指擡起時間判斷是否有觸控事件

2. 監聽手指觸控事件

package com.android.server.power;

import android.content.Context;
import android.os.Build;
import android.os.Handler;
import android.os.Looper;
import android.os.SystemClock;
import android.util.Slog;
import android.view.GestureDetector;
import android.view.InputDevice;
import android.view.MotionEvent;
import android.view.WindowManagerPolicy.PointerEventListener;

public class SystemTouchEventListener implements PointerEventListener {

    private static final String TAG = "PowerController.SysTouchEvt";

    private final boolean DEBUG = isDebug();
    private final boolean DEBUG_MORE = false;
    private final boolean TEST = PowerController.TEST;

    private final Context mContext;
    private final Callbacks mCallbacks;


    public SystemTouchEventListener(Context context, Callbacks callbacks) {
        mContext = context;
        mCallbacks = callbacks;
    }

    @Override
    public void onPointerEvent(MotionEvent event) {
        if (!event.isTouchEvent()) {
            return;
        }
        switch (event.getActionMasked()) {
            case MotionEvent.ACTION_DOWN:
                //if (DEBUG) Slog.d(TAG, "Event " + event);
                if (mCallbacks != null)
                    mCallbacks.onDown();
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                break;
            case MotionEvent.ACTION_MOVE:
                break;
            case MotionEvent.ACTION_HOVER_MOVE:
                break;
            case MotionEvent.ACTION_UP:
                // 手指擡起
                //if (DEBUG) Slog.d(TAG, "Event " + event);
                if (mCallbacks != null)
                    mCallbacks.onUp();
                break;
            case MotionEvent.ACTION_CANCEL:
                break;
            default:
                if (DEBUG) Slog.d(TAG, "Ignoring " + event);
        }
    }


    interface Callbacks {
        void onDown();
        void onUp();
    }

    private boolean isDebug(){
        return Build.TYPE.equals("eng") || Build.TYPE.equals("userdebug");
    }
}

 

3. 記錄手指擡起時的時間戳

    // system touch event listener
    private SystemTouchEventListener mSystemTouchEventListener;
    private WindowManagerFuncs mWindowManagerFuncs;
    private long mLastTouchEventTimeStamp = 0;

    // register system touch event listener
    private void registerTouchEventListener() {
        mSystemTouchEventListener = new SystemTouchEventListener(mContext, new SystemTouchEventListener.Callbacks() {

            @Override
            public void onDown() {

            }

            @Override
            public void onUp() {
                mLastTouchEventTimeStamp = SystemClock.elapsedRealtime();
                if (DEBUG) Slog.d(TAG, "TouchEvent Up: mLastTouchEventTimeStamp:" + mLastTouchEventTimeStamp);
            }
        });

        if (mWindowManagerFuncs != null) {
            mWindowManagerFuncs.registerPointerEventListener(mSystemTouchEventListener);
        }
    }
 

4. 判斷是否有使用者觸控行為

如果當前時間與上一次手指擡起的時間只差小於1秒，則使用者正在進行觸控行為。
當然也可以使用down事件進行判斷

    private boolean isUserTouchActive() {

        long now = SystemClock.elapsedRealtime();

        long lastTouchTime = 0;
        if (mPowerControllerInternal != null)
            lastTouchTime = mPowerControllerInternal.getLastTouchEventTimeStamp();

        return ((now - lastTouchTime) <= 1000);
    }