android 多手勢識別

package com.example.map_js;

import com.example.utils.LogToastSysUtils;

import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnLongClickListener;
import android.view.View.OnTouchListener;

public class WebViewTouch implements OnTouchListener {

	RunJavaScript rjs;
	float eventDown;
	float evnetUp;
	boolean isPress = false;
	Handler handler = new Handler();

	public WebViewTouch(RunJavaScript rjs) {
		super();
		this.rjs = rjs;
	}

	@Override
	public boolean onTouch(View v, MotionEvent event) {
		int action = event.getAction();
		printLog("action-->"+action);
		switch (action) {
		case MotionEvent.ACTION_DOWN:
			printLog("ACTION_DOWN");
			isPress = true;
			//模擬長按事件
			handler.postDelayed(longClick, 500);
			break;
		case MotionEvent.ACTION_UP:
			printLog("ACTION_UP");
			isPress = false;
			break;
		}
		
		//多手勢時返回的 第二個按下是261 彈起的時候是262 運算後
		switch (action & MotionEvent.ACTION_MASK) {
		case MotionEvent.ACTION_POINTER_DOWN:
			printLog("ACTION_POINTER_DOWN");
			eventDown = dis(event);
			break;
		case MotionEvent.ACTION_POINTER_UP:
			printLog("ACTION_POINTER_UP");
			evnetUp = dis(event);
			int t = calEvent(eventDown, evnetUp);
			if (t == 1) {
				rjs.mapBig();
				return true;
			} else if (t == -1) {
				rjs.mapSmall();
				return true;
			}
			break;
		default:
			break;
		}
		return false;
	}

	private void printLog(String str) {
		LogToastSysUtils.printLog("WebViewTouch", str);
	}
	//根據按下和彈起兩個點之間的距離差的差
	private int calEvent(float eventDown, float eventUp) {
		float t = eventDown - eventUp;
		printLog("(eventDown-eventUp)-->" + (eventDown - eventUp));
		if (t > 20f) {
			return -1;
		} else if (t < -20f) {
			return 1;
		}
		return 0;
	}
	//計算兩個手勢間的距離
	private float dis(MotionEvent event) {
		return Math.abs(event.getX(0) - event.getX(1));
	}

	private Runnable longClick = new Runnable() {
		@Override
		public void run() {
			if (isPress) {
				// rjs.mapChangeType();
			}
		}
	};
}