Question

我需要有关从TouchEvent获取信息的帮助。例如，如果我绘制一条线，我需要ACTION_DOWN已经启动的信息以及该操作已经完成的位置（例如：started：top，finished：left）。我包括图像所以这可以更清楚。

http://i.imgur.com/ILEEHT5.png

这是代码（用于绘图）：

    package com.mmilosanovic.trafficcounting;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.os.Bundle;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class JunctionView extends View {

    private Paint paint = new Paint();
    private Path path = new Path();

    public JunctionView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub

        paint.setAntiAlias(true);
        paint.setStrokeWidth(6f);
        paint.setColor(Color.BLUE);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeJoin(Paint.Join.ROUND);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        super.onDraw(canvas);
        canvas.drawPath(path, paint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        float eventX = event.getX();
        float eventY = event.getY();

        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(eventX, eventY);
            return true;
        case MotionEvent.ACTION_MOVE:
            path.lineTo(eventX, eventY);
            break;
        case MotionEvent.ACTION_UP:

            break;
        default:
            return false;
        }
        invalidate();
        return true;
    }
}

提前致谢。

Answer 1

您需要自己跟踪动作。创建类float startX, startY之类的类变量，并在获得ACTION_DOWN时分配给它们。然后，当您获得ACTION_UP时，您可以与这些值进行比较。

Answer 2

您可以使用：

@Override
public boolean onTouchEvent(MotionEvent event) {
    int x = (int)event.getX();
    int y = (int)event.getY();
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
        Toast.makeText(activity, "Down", Toast.LENGTH_SHORT).show();
        break;
        case MotionEvent.ACTION_MOVE:
        Toast.makeText(activity, "Move", Toast.LENGTH_SHORT).show();
        break;
        case MotionEvent.ACTION_UP:
        Toast.makeText(activity, "Up", Toast.LENGTH_SHORT).show();
        break;
    }
return false;
}

Answer 3

如何获取ACTION已从顶部开始并已在屏幕左侧完成的信息？

如何从TouchEvent获取信息？

3 个答案: