Android自定义控件的属性(2)

二、如何创建自己的View

继承View或者它的子类，然后重写构造函数和onDraw函数。看看代码：

package com.wenix;

import Android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

public class MyView extends View {
 private static final String TAG = "MyView";
 private Paint mPaint;
 Drawable background;
 
 public MyView(Context context) {
  // TODO Auto-generated constructor stub
  super(context);
 }
 
 public MyView(Context context, AttributeSet attrs) {
  super(context, attrs);
  // TODO Auto-generated constructor stub
  mPaint = new Paint();
  TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.MyView);//得到属性数组
 
  int textColor = a.getColor(R.styleable.MyView_textColor, Color.BLUE);//得到属性值，可以指定默认值，防止空值，注意引用名。
  float textSize = a.getDimension(R.styleable.MyView_textSize, 22);//注意get方法，跟format是一致的。
  background = a.getDrawable(R.styleable.MyView_background);
 
  mPaint.setColor(textColor);
  mPaint.setTextSize(textSize);
 
  a.recycle();//一定要recycle以下来保证属性值一致。
 }
 
 @Override
 protected void onDraw(Canvas canvas) {
  // TODO Auto-generated method stub
  super.onDraw(canvas);
  mPaint.setStyle(Style.FILL);

Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.myview_background);
  canvas.drawBitmap(bitmap, 0, 0, mPaint);
//  Matrix matrix = new Matrix();
//  matrix.postScale(0, 0, 480, 800);
//  canvas.drawBitmap(bitmap, matrix, mPaint);
 
 
  mPaint.setColor(Color.RED);
  canvas.drawText("hello,world!", 20, 55, mPaint);
 }

}