Android开始之 扩展存储sdcard

 1     //---------------------写-----------------------
 2     public boolean saveFileToSdcard(String fileName, byte[] data) {
 3         boolean flag = false;
 4         // 先判断sdcard的状态；
 5         String state = Environment.getExternalStorageState();
 6         // 表示sdcard挂载在手机上，并且可以读写
 7         FileOutputStream outputStream = null;
 8         // 获得sdcard的根目录/mnt/sdcard/.....
 9         File root = Environment.getExternalStorageDirectory();
10 
11         if (state.equals(Environment.MEDIA_MOUNTED)) {
12             // File file =new File(root, fileName);//在sdcard根目录上创建一个文件
13             File file = new File(root.getAbsolutePath() + "/txt");// 创建一个TXT文件夹再存
14             if (!file.exists()) {
15                 file.mkdirs();
16             }
17             try {
18                 // outputStream=new FileOutputStream(file);
19                 outputStream = new FileOutputStream(new File(file, fileName));
20                 outputStream.write(data, 0, data.length);
21                 flag = true;
22             } catch (Exception e) {
23                 // TODO: handle exception
24                 e.printStackTrace();
25             } finally {
26                 if (outputStream != null) {
27                     try {
28                         outputStream.close();
29                     } catch (Exception e2) {
30                         // TODO: handle exception
31                         e2.printStackTrace();
32                     }
33 
34                 }
35 
36             }
37 
38         }
39         return flag;
40     }

1 public void save(){
2         FileService service=new FileService();
3         service.saveFileToSdcard("aa.txt", "zy520".getBytes());
4     
5     }

 1 //----------------------------------读文件内容-----------------------
 2     public String readContextFromSdcard(String fileName) {
 3         File root=Environment.getExternalStorageDirectory();
 4         FileInputStream inputStream=null;
 5         ByteArrayOutputStream outputStream=new ByteArrayOutputStream();
 6         if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
 7             File file = new File(root.getAbsolutePath() + "/txt/");    
 8             File file2=new File(file, fileName);
 9             int len=0;
10             byte[]data=new byte[1024];
11             
12             
13             if (file2.exists()) {
14                 try {
15                     inputStream=new FileInputStream(file2);    
16                 while((len=inputStream.read(data))!=-1){
17                     outputStream.write(data, 0, len);
18                     
19                 
20                 }
21                 return new String(outputStream.toByteArray());
22                 } catch (Exception e) {
23                     // TODO: handle exception
24                     e.printStackTrace();
25                 }finally{
26                     if (inputStream!=null) {
27                         try {
28                             inputStream.close();
29                         } catch (Exception e2) {
30                             // TODO: handle exception
31                             e2.printStackTrace();
32                         }
33                         
34                     }
35                 }
36             
37             }
38         }
39         
40         return null;
41     }

1     public void read(){
2         FileService service=new FileService();
3         String msg =service.readContextFromSdcard("aa.txt");
4         System.out.println("---->>"+msg);
5         
6         
7     }

 1 public class ImageCache {
 2     public static String saveImageCache(String fileName, byte[] data) {
 3 
 4         File file = Environment.getExternalStorageDirectory();
 5         FileOutputStream outputStream = null;
 6         if (Environment.getExternalStorageState().equals(
 7                 Environment.MEDIA_MOUNTED)) {
 8             try {
 9                 outputStream = new FileOutputStream(new File(file, fileName));
10                 outputStream.write(data, 0, data.length);
11                 
12                 return file.getAbsolutePath()+"/"+fileName;
13             } catch (Exception e) {
14                 // TODO: handle exception
15                 e.printStackTrace();
16             }finally{
17                 if (outputStream!=null) {
18                 try {
19                     outputStream.close();
20                 } catch (Exception e2) {
21                     // TODO: handle exception
22                     e2.printStackTrace();
23                 }
24                 }
25             }
26         }
27 
28         return null;
29     }
30 }

 1 public class MainActivity extends ActionBarActivity {
 2     private Button button;
 3     private ImageView imageView;
 4     private ProgressDialog dialog;
 5     private String path ="https://www.baidu.com/img/bd_logo1.png";
 6 
 7     @Override
 8     protected void onCreate(Bundle savedInstanceState) {
 9         super.onCreate(savedInstanceState);
10         setContentView(R.layout.fragment_main);
11         dialog = new ProgressDialog(this);
12         dialog.setTitle("提示");
13         dialog.setMessage("load.....");
14         button = (Button) findViewById(R.id.button1);
15         imageView = (ImageView) findViewById(R.id.imageView1);
16         button.setOnClickListener(new View.OnClickListener() {
17 
18             @Override
19             public void onClick(View v) {
20                 // TODO Auto-generated method stub
21                 new MyTask().execute(path);
22             }
23         });
24 
25     }
26 
27     class MyTask extends AsyncTask<String, Void, byte[]> {
28         private String imageName;
29         @Override
30         protected void onPreExecute() {
31             // TODO Auto-generated method stub
32             super.onPreExecute();
33             dialog.show();
34         }
35 
36         @Override
37         protected byte[] doInBackground(String... params) {
38             // TODO Auto-generated method stub
39             try {
40                 String name=params[0];
41                 //截取图片名称：bd_logo1.png
42                 imageName=name.substring(name.lastIndexOf("/")+1, name.length());
43             } catch (Exception e) {
44                 // TODO: handle exception
45             }
46             
47             return HttpUtils.getImage(params[0]);
48         }
49 
50         @Override
51         protected void onPostExecute(byte[] result) {
52             // TODO Auto-generated method stub
53             super.onPostExecute(result);
54             if (result != null) {
55                 Bitmap bitmap=BitmapFactory.decodeByteArray(result, 0, result.length);
56                 imageView.setImageBitmap(bitmap);
57                 ImageCache.saveImageCache(imageName, result);
58 
59             } else {
60                 imageView.setImageResource(R.drawable.ic_launcher);
61             }
62 
63             dialog.dismiss();
64         }
65 
66     }

 1 public class HttpUtils {
 2 public static byte[] getImage(String path){
 3     byte[]data=null;
 4     HttpClient httpClient=new DefaultHttpClient();
 5     HttpPost post =new HttpPost(path);
 6     try {
 7             HttpResponse response=httpClient.execute(post);
 8     
 9     if (response.getStatusLine().getStatusCode()==200) {
10         data=EntityUtils.toByteArray(response.getEntity());
11     }
12     } catch (Exception e) {
13         // TODO: handle exception
14         e.printStackTrace();
15     }finally{
16         httpClient.getConnectionManager().shutdown();
17     }
18 
19     
20     return data;
21 }
22 }

 1 //---------------保存指定的SDcard目录----------
 2     public void saveFileToSdcardBySuff(String fileName,byte [] data){
 3         
 4         //保存文件的目录
 5         File file=null;
 6         if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
 7             if (fileName.endsWith(".mp3")) {
 8                 file=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC);
 9                 
10             }else if (fileName.endsWith(".jpg")||fileName.endsWith(".png")||fileName.endsWith(".gif")) {
11                 file=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
12             }else if (fileName.endsWith(".mp4")||fileName.endsWith(".3gp")) {
13                 file=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
14                 
15             }else {
16                 file=Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
17             }
18         }
19         FileOutputStream outputStream=null;
20         try {
21             outputStream=new FileOutputStream(new File(file,fileName));
22             outputStream.write(data,0, data.length);
23         } catch (Exception e) {
24             // TODO: handle exception
25             e.printStackTrace();
26         }finally{
27             try {if (outputStream!=null) {
28                 outputStream.close();
29             }
30                 
31             } catch (Exception e2) {
32                 // TODO: handle exception
33             }
34             
35         }
36         
37     }

1 public void save2(){
2         FileService service=new FileService();
3         service.saveFileToSdcardBySuff("aa.txt", "zy520".getBytes());
4     
5     }
6     

public boolean deleteFileFromSdcard(String folder,String fileName){
    boolean flag=false;
    File file=Environment.getExternalStorageDirectory();
    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
        File exitfile=new File(file.getAbsolutePath()+"/"+folder+"/"+fileName);
        if (exitfile.exists()) {
            flag=exitfile.delete();
            
        }
    }
    
    
    return flag;
    
}

1 public void del(){
2         FileService service=new FileService();
3         boolean flag =service.deleteFileFromSdcard("txt","aa.txt");
4         System.out.println("---->>"+flag);
5         
6         
7     }