1 package cc.sp; 2  3 import java.io.ByteArrayInputStream; 4 import java.io.ByteArrayOutputStream; 5 import android.os.Bundle; 6 import android.util.Base64; 7 import android.view.View; 8 import android.view.View.OnClickListener; 9 import android.widget.Button;10 import android.widget.ImageView;11 import android.app.Activity;12 import android.content.Context;13 import android.content.SharedPreferences;14 import android.content.SharedPreferences.Editor;15 import android.graphics.Bitmap;16 import android.graphics.Bitmap.CompressFormat;17 import android.graphics.BitmapFactory;18 /**19  * Demo描述:20  * 利用SharedPreferences存取图片21  * 22  * 23  * 参考资料:24  * 1 http://blog.csdn.net/tangnengwu/article/details/3788108725  * 2 http://blog.csdn.net/lfdfhl/article/details/3774277526  * 3 http://blog.csdn.net/lfdfhl/article/details/1799846927  * 4 http://blog.csdn.net/lfdfhl/article/details/1096145928  *   Thank you very much29  *30  */31 public class MainActivity extends Activity {32     private Button mSaveButton;33     private Button mGetButton;34     private ImageView mImageView;35     @Override36     protected void onCreate(Bundle savedInstanceState) {37         super.onCreate(savedInstanceState);38         setContentView(R.layout.main);39         init();40     }41     42     private void init(){43         mSaveButton=(Button) findViewById(R.id.saveButton);44         mSaveButton.setOnClickListener(new OnClickListener() {45             @Override46             public void onClick(View view) {47                 saveBitmapToSharedPreferences();48             }49         });50         mGetButton=(Button) findViewById(R.id.getButton);51         mGetButton.setOnClickListener(new OnClickListener() {52             @Override53             public void onClick(View view) {54                 getBitmapFromSharedPreferences();55             }56         });57         mImageView=(ImageView) findViewById(R.id.imageView);58     }59 60     61     /**62      * 将Bitmap转换成字符串保存至SharedPreferences63      * 64      * 注意:65      * 在压缩图片至输出流时,不要选择CompressFormat.JPEG而该是PNG,否则会造成图片有黑色背景.66      * 详见参考资料二67      */68     private void saveBitmapToSharedPreferences(){69         Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);70         //第一步:将Bitmap压缩至字节数组输出流ByteArrayOutputStream71         ByteArrayOutputStream byteArrayOutputStream=new ByteArrayOutputStream();72         bitmap.compress(CompressFormat.PNG, 80, byteArrayOutputStream);73         //第二步:利用Base64将字节数组输出流中的数据转换成字符串String74         byte[] byteArray=byteArrayOutputStream.toByteArray();75         String imageString=new String(Base64.encodeToString(byteArray, Base64.DEFAULT));76         //第三步:将String保持至SharedPreferences77         SharedPreferences sharedPreferences=getSharedPreferences("testSP", Context.MODE_PRIVATE);78         Editor editor=sharedPreferences.edit();79         editor.putString("image", imageString);80         editor.commit();81     }82     83     84     /**85      * 从SharedPreferences中取出Bitmap86      */87     private void getBitmapFromSharedPreferences(){88         SharedPreferences sharedPreferences=getSharedPreferences("testSP", Context.MODE_PRIVATE);89         //第一步:取出字符串形式的Bitmap90         String imageString=sharedPreferences.getString("image", "");91         //第二步:利用Base64将字符串转换为ByteArrayInputStream92         byte[] byteArray=Base64.decode(imageString, Base64.DEFAULT);93         ByteArrayInputStream byteArrayInputStream=new ByteArrayInputStream(byteArray);94         //第三步:利用ByteArrayInputStream生成Bitmap95         Bitmap bitmap=BitmapFactory.decodeStream(byteArrayInputStream);96         mImageView.setImageBitmap(bitmap);97     }98     99 }

 1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 2     xmlns:tools="http://schemas.android.com/tools" 3     android:layout_width="match_parent" 4     android:layout_height="match_parent" 5    > 6  7     <Button 8         android:id="@+id/saveButton" 9         android:layout_width="wrap_content"10         android:layout_height="wrap_content"11         android:text="保存图片到SharedPreferences" 12         android:layout_centerHorizontal="true"13         android:layout_marginTop="25dip"/>14     15      <Button16         android:id="@+id/getButton"17         android:layout_width="wrap_content"18         android:layout_height="wrap_content"19         android:text="从SharedPreferences获取图片" 20         android:layout_centerHorizontal="true"21         android:layout_marginTop="80dip"/>22      23      24      <ImageView 25         android:id="@+id/imageView"26         android:layout_width="wrap_content"27         android:layout_height="wrap_content"28         android:layout_centerInParent="true"29         />30 31 </RelativeLayout>