【发布时间】:2011-05-04 21:50:58
【问题描述】:
我有一个名为 dot 的类,并且在应用程序运行时会创建同一个类的许多实例。问题是我需要能够点击这个类的一个实例并且让点击的实例只改变颜色。
问题是每当我点击其中一个点实例时,它们都会改变颜色,而不仅仅是我点击的那个。
代码如下:
package com.ewebapps;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.MotionEvent;
import android.view.View;
public class Dot extends View {
private final float x;
private final float y;
private final int r;
private final Paint mBlack = new Paint(Paint.ANTI_ALIAS_FLAG);
private final Paint mWhite = new Paint(Paint.ANTI_ALIAS_FLAG);
private final Paint mGreen = new Paint(Paint.ANTI_ALIAS_FLAG);
private boolean touched;
public Dot(Context context, float x, float y, int r) {
super(context);
mBlack.setColor(0xFF000000); //Black
mWhite.setColor(0xFFFFFFFF); //White
mGreen.setColor(0xFF00FF00); //Green
this.x = x;
this.y = y;
this.r = r;
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) { // On touch.
touched = true;
//mPaint.setColor(0xFF00FF00); // Turn dot green.
this.invalidate();
return super.dispatchTouchEvent(event);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawCircle(x, y, r+2, mWhite); //White stroke.
if(!touched)
{
canvas.drawCircle(x, y, r, mBlack); //Black circle.
}
else
{
canvas.drawCircle(x, y, r, mGreen); //Green circle.
}
}
}
【问题讨论】:
标签: android instance private public touch-event