Android开发之大位图压缩水印处置

      我们在发微博或者csdn博文的时候都可以给图片加上一个水印，一个独立的标识，那是怎么实现的呢？先封装一个BitmapTools封装类，该类要解决的问题是一将突破存储至sdcard中，二给图片加上水印。

BitmapTools

package com.example.g11_bitmap04;import java.io.File;import java.io.FileOutputStream;import java.io.OutputStream;import android.content.res.Resources;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Paint;import android.os.Environment;public class BitmapTools {		public BitmapTools() {		// TODO Auto-generated constructor stub	}	public static Bitmap createBitmap(Resources resources, int resid,			String name) {		Bitmap bitmap=BitmapFactory.decodeResource(resources, resid);		//复制一份新的Bitmap,因为不能直接在原有的bitmap上进行水印操作		//Bitmap.config存储的格式		Bitmap newBitmap=bitmap.copy(Bitmap.Config.ARGB_8888, true);		//使用自定义画布		Canvas canvas=new Canvas(newBitmap);		Paint paint=new Paint();		paint.setTextSize(200);		canvas.drawText("hello", 100, 100, paint);		//判断SDcard是否在可用状态		if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){			//直接将图片保存在根目录下			File root=Environment.getExternalStorageDirectory();			OutputStream outputStream=null;			try {								outputStream=new FileOutputStream(new File(root, name));				//对图片进行压缩并以png格式，保存在sdcard中				newBitmap.compress(Bitmap.CompressFormat.PNG, 50, outputStream);			} catch (Exception e) {				// TODO: handle exception			}		}		return newBitmap;	}}

package com.example.g11_bitmap04;import android.os.Bundle;import android.app.Activity;import android.graphics.Bitmap;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.ImageView;public class MainActivity extends Activity {     private ImageView imageView;     private Button button;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		imageView=(ImageView)this.findViewById(R.id.imageView1);		button=(Button)this.findViewById(R.id.button1);		button.setOnClickListener(new View.OnClickListener() {						@Override			public void onClick(View v) {				// TODO Auto-generated method stub								Bitmap bitmap=BitmapTools.createBitmap(getResources(), R.drawable.a, "a.png");				imageView.setImageBitmap(bitmap);			}		});	}	@Override	public boolean onCreateOptionsMenu(Menu menu) {		// Inflate the menu; this adds items to the action bar if it is present.		getMenuInflater().inflate(R.menu.main, menu);		return true;	}}