学步园

1 主要有三个按钮一个imageview三个功能

package com.example.b;

import android.app.Activity;
import android.os.Bundle;

import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class DrawActivity extends Activity {

	ImageView iv;
	Button btn1, btn2, btn3, btn4;
	Resources r;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.paint);
		iv = (ImageView) this.findViewById(R.id.ImageView01);
		btn1 = (Button) this.findViewById(R.id.Button01);
		btn2 = (Button) this.findViewById(R.id.Button02);
		btn3 = (Button) this.findViewById(R.id.Button03);

		btn1.setOnClickListener(new ClickEvent());
		btn2.setOnClickListener(new ClickEvent());
		btn3.setOnClickListener(new ClickEvent());

		r = this.getResources();

	}

	class ClickEvent implements View.OnClickListener {

		public void onClick(View v) {
			if (v == btn1)// 显示资源图片
			{// 功能等效
				// iv.setBackgroundResource(R.drawable.icon);//打开资源图片
				Bitmap bmp = BitmapFactory.decodeResource(r, R.drawable.icon);// 打开资源图片
				iv.setImageBitmap(bmp);
			} else if (v == btn2)// 显示并绘画资源图片
			{
				Bitmap bmp = BitmapFactory.decodeResource(r, R.drawable.icon);// 只读,不能直接在bmp上画
				Bitmap newb = Bitmap.createBitmap(300, 300, Config.ARGB_8888);

				Canvas canvasTemp = new Canvas(newb);
				canvasTemp.drawColor(Color.TRANSPARENT);

				Paint p = new Paint();
				String familyName = "宋体";
				Typeface font = Typeface.create(familyName, Typeface.BOLD);
				p.setColor(Color.RED);
				p.setTypeface(font);
				p.setTextSize(22);
				canvasTemp.drawText("写字。。。", 50, 50, p);
				canvasTemp.drawBitmap(bmp, 50, 50, p);// 画图
				iv.setImageBitmap(newb);
			} else if (v == btn3)// 直接在Button上绘图
			{
				Bitmap newb = Bitmap.createBitmap(btn3.getWidth(),
						btn3.getHeight(), Config.ARGB_8888);
				Canvas canvasTemp = new Canvas(newb);
				canvasTemp.drawColor(Color.WHITE);
				Paint p = new Paint();
				String familyName = "宋体";
				Typeface font = Typeface.create(familyName, Typeface.BOLD);
				p.setColor(Color.RED);
				p.setTypeface(font);
				p.setTextSize(20);
				canvasTemp.drawText("写字。。。", 30, 30, p);
				Drawable drawable = new BitmapDrawable(newb);
				btn3.setBackgroundDrawable(drawable);
			}
		}

	}

}

2

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <Button android:id="@+id/Button01" android:layout_width="fill_parent" android:layout_height="44px" android:text="显示资源图片"></Button>  
	<Button android:id="@+id/Button02" android:layout_width="fill_parent" android:layout_height="44px" android:text="显示并绘画资源图片"></Button>  
	<Button android:id="@+id/Button03" android:layout_height="44px" android:layout_width="fill_parent" android:text="在控件上绘图"></Button>  
	<ImageView android:id="@+id/ImageView01" android:layout_width="wrap_content" android:layout_height="wrap_content"></ImageView>  

</LinearLayout>

3 结果