andriod view的子类

package com.norwaya.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

import com.example.norwaya.R;

public class PlaneView extends View {
    private Bitmap plane;
    Paint p;
    float currentX;
    float currentY;

    public PlaneView(Context context) {
        super(context, null);

    }

/** 如果用xml来配置这个view 一定要重写这个方法，否则会报错，很难查找 */


    public PlaneView(Context context, AttributeSet attr) {
        super(context, attr);
        p = new Paint();
        plane = BitmapFactory.decodeResource(getResources(),
                R.drawable.ic_album_black_18dp);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawBitmap(plane, currentX, currentY, p);

    }
}