package com.android.test;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View;
public class TestActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new TestView(this));
}
public class TestView extends View {
private Paint mPaint = new Paint();
public TestView(Context context) {
super(context);
}

@Override
protected void onDraw(Canvas canvas) { 
  // TODO Auto-generated method stub 
  super.onDraw(canvas); 
    
  String text = "Android - 机器人";      
  mPaint.setColor(Color.WHITE); 
    
  Paint paint = new Paint(); 
  paint.setColor(Color.RED); 
    
  String familyName = "宋体"; 
  Typeface font = Typeface.create(familyName,Typeface.BOLD); 
  paint.setTypeface(font); 
    
  paint.setTextSize(22); 
    
  canvas.drawRect(new Rect(0, 0, 320, 240), mPaint); 
  canvas.drawText(text, 0, 100, paint); 
} 

}
}

或者再回调函数中用Invalidate();一下就可以回调到ondraw的方法