自定义View绘制字符串

 import android.app.Activity;
 import android.os.Bundle;
 import android.view.Display;
 import android.view.View;
 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Paint.FontMetrics;  
 public class MainActivity extends Activity {  
     public int nScreenWidth = 0;
     public int nScreenHeight = 0;
     Paint paint = null;  
     @Override
     protected void onCreate(Bundle savedInstanceState) {  
         //  获取屏幕宽高
         Display display = getWindowManager().getDefaultDisplay();
         nScreenWidth = display.getWidth();
         nScreenHeight = display.getHeight();  
         super.onCreate(savedInstanceState);
         setContentView(new FontView(this));
     }  
     //  自定义的View
     class FontView extends View {
         public final static String STR_WIDTH = "获取字符宽度为：";
         public final static String STR_HEIGHT = "获取字符高度为：";  
         public FontView(Context context) {
             super(context);
             // TODO Auto-generated constructor stub
             paint = new Paint();
         }  
         @Override
         protected void onDraw(Canvas canvas) {
             super.onDraw(canvas);
             //  设置背景色
             setBackgroundColor(Color.BLACK);  
             //  设置字符串颜色
             paint.setColor(Color.WHITE);
             canvas.drawText("当前屏幕宽"+nScreenWidth, 0, 30, paint);
             canvas.drawText("当前屏幕高"+nScreenHeight, 0, 60, paint);  
             //  设置字体大小
             paint.setColor(Color.RED);
             paint.setTextSize(18);
             canvas.drawText("字体大小为18", 0, 90, paint);  
             //  消除字体锯齿
             paint.setFlags(Paint.ANTI_ALIAS_FLAG);
             canvas.drawText("消除字体锯齿", 0, 120, paint);  
             //  获取字符串宽度
             canvas.drawText(STR_WIDTH + getStringWidth(STR_WIDTH), 0, 150, paint);  
             //  获取字体高度
             canvas.drawText(STR_HEIGHT + getFontHeight() , 0, 180, paint);  
         }  
         //  获取字体串宽度
         private int getStringWidth(String str) {
             return (int) paint.measureText(str);
         }  
         //  获取字体高度
         private int getFontHeight() {
             FontMetrics fm = paint.getFontMetrics();
             return (int) Math.ceil(fm.descent - fm.top) + 2;
         }
     }
 }