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在我的程序中，我在模拟器上收到此错误。如果我在我的 Razr MAXX 上运行它，它可以工作吗？它说

10-28 19:38:27.935: E/AndroidRuntime(2268): java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.

错误发生在这一行：layout.addView(mid)

我相信它说 mid 已经有一个父级，所以我进行了调试，ViewGroup parent = (ViewGroup) mid.getParent();它返回 null ...

有人可以引导我朝着正确的方向前进吗？

下面是我的课：

package com.example.draganddroptest;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;

/**
 * @author Brandon Ling
 * 
 */
public class HoneycombView extends View {
    private Context context;
    private ViewGroup layout;
    private HexagonView top;
    private HexagonView topRight;
    private HexagonView topLeft;
    private HexagonView bot;
    private HexagonView botLeft;
    private HexagonView botRight;
    private HexagonView mid;
    private int radius;
    private PointF shift;
    private String color;
    private String[] colors;
    private int strokeWidth;

    Paint paint = new Paint();

    /**
     * @param context
     * @param layout
     */
    public HoneycombView(Context context, AttributeSet attrs) {
        this(context, null, 0, null, null, attrs, 0);
    }

    public HoneycombView(Context context, ViewGroup layout, int radius, PointF shift, String color, AttributeSet attrs, int strokeWidth) {
        super(context);
        this.context = context;

        if (attrs != null) { // probably sent via xml
            TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.HoneycombView);
            this.radius = a.getInt(R.styleable.HoneycombView_radius, this.strokeWidth);
            this.shift = new PointF(a.getInt(R.styleable.HoneycombView_shiftX, 0), a.getInt(
                    R.styleable.HoneycombView_shiftY, 0));
            this.colors = a.getString(R.styleable.HoneycombView_hexColors).split("\\|");
            a.recycle();
        } else {
            this.layout = layout;
            this.radius = radius;
            this.shift = shift;
            this.color = color;
        }
        this.mid = new HexagonView(this.context, null, this.radius, this.shift, this.colors[0], 10);
        this.top = mid.addHexTop(colors[1]);
        this.topRight = mid.addHexTopRight(colors[2]);
        this.topLeft = mid.addHexTopLeft(colors[3]);
        this.bot = mid.addHexBot(colors[4]);
        this.botRight = mid.addHexBotRight(colors[5]);
        this.botLeft = mid.addHexBotLeft(colors[6]);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        this.layout = (ViewGroup) this.getParent();
        ViewGroup parent = (ViewGroup) mid.getParent();
        //parent.removeAllViews();
        layout.addView(mid);
        layout.addView(top);
        layout.addView(topRight);
        layout.addView(topLeft);
        layout.addView(bot);
        layout.addView(botRight);
        layout.addView(botLeft);


    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int height = (int) Math.ceil(this.bot.getMaxY()) + this.strokeWidth;
        int width = (int) Math.ceil(this.botRight.getMaxX()) + this.strokeWidth;
        setMeasuredDimension(width, height);
    }
}
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1 回答 1

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  1. onDraw()被Android反复调用。第二次调用onDraw()将抛出此异常，因为每个View都已添加到父级。

  2. 也就是说，作为一项规则，您永远不会更改内部的布局onDraw()。此方法仅适用于绘画Canvas。即使您设法通过调用来修复此异常removeAllViews()（看起来您可能已经尝试过），您仍将强制 Android 在删除和重新添加视图时一次又一次地不断测量和绘制布局。

  3. 您可能实际上并不想将您的子视图添加到父视图。如果要添加子视图，则应将它们添加为HoneyCombView. 为此，您需要扩展ViewGroup而不是View. 再次，将子视图添加到其他地方，而不是onDraw().

  4. 尽管将子视图添加到ViewGroup遗嘱中是可行的，但它对性能并不是很好。您添加到布局的每个子视图都会减慢应用程序的速度。（请参阅使用更少的视图。）更好的选择是将形状直接绘制到Canvasusing (for example)上canvas.drawPath()。

于 2013-10-28T20:07:41.790 回答