Question

我有一个扩展视图的类。下面是构造函数。在构造函数中，我将值赋给private int r,g,b;。分配正确的值。

public CanvasView(Context c, int r, int g, int b) {
        super(c);
        context = c;
        this.r = r;
        this.g = g;
        this.b = b;

    Log.i("RGB:", "r" + r + "g" + g + "b" + b); //logs correct values

}

在onDraw（见下文）中，当我访问所有值时，它们都为零。

@Override
    protected void onDraw(final Canvas canvas) {
        super.onDraw(canvas);

        hsv = new float[3];

        Color.RGBToHSV(r, g, b, hsv);

        hsv[2] = getVal();

        Log.i("RGBdraw:", "r" + r + "g" + g + "b" + b); //values are all 0

        if (canvas != null){

            canvas.drawColor(Color.rgb(r, g, b));
        }



    }

我认为在分配私有变量时，它们可以访问整个类吗？非常感谢任何帮助。

修改这是最小的例子

在另一个课程中，我创建了视图CanvasView mCanvasView = new CanvasView(mContext, 255, 0, 171);

以下是名为CanvasView的类，它由上面的代码创建。我将3个整数传递给CanvasView。

public class CanvasView extends View {

private Context context;
private int r,g,b;

public CanvasView(Context c, int r, int g, int b) {
    super(c);
    context = c;
    this.r = r;
    this.g = g;
    this.b = b;

    Log.i("RGB:", "r" + r + "g" + g + "b" + b); //Correct values are logged

}

@Override
protected void onDraw(final Canvas canvas) {
    super.onDraw(canvas);

    Log.i("RGB draw:", "r" + r + "g"+g + "b"+b); //Values here are all 0

    if (canvas != null){
        canvas.drawColor(Color.rgb(r, g, b));
    }

}

}

Answer 1

而不是像在java中那样创建类：CanvasView mCanvasView = new CanvasView(mContext, 255, 0, 171);

以android方式创建类：CanvasView mView = (CanvasView) findViewById(R.id.canvasView);

然后使用红绿蓝的getter和setter

public void red(int r){
        this.r = r;
    }

    public int getRed(){
        return r;
    }

传递如下值：mView.red(255);

访问分配的私有变量时，它们返回0

1 个答案: