Android---36---讀取SD卡內容

標籤：android

1.調用Environment.getExternalStorageState()判斷手機上是否插入了SD卡，並且應用程式具有讀寫SD卡的許可權。
Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)


返回值為true代表該應用程式具有讀寫SD卡的許可權。


2.調用Environment的getExternalStorageDirectory()方法來擷取外部儲存空間，也就是SD卡的目錄。

3.使用FileInputStream FileOutputStream FileReader  FIleWriter 讀寫SD卡裡的檔案。

class Utils {public void MyWrite(String data) throws Exception {File sDfile = Environment.getExternalStorageDirectory();File f = new File(sDfile, "demo.txt");FileOutputStream fos = new FileOutputStream(f);fos.write(data.getBytes());fos.flush();fos.close();}public String MyRead() throws Exception {File sdFile = Environment.getExternalStorageDirectory();File f = new File(sdFile, "demo.txt");FileInputStream fis = new FileInputStream(f);StringBuffer sb = new StringBuffer();int len = 0;while ((len = fis.read()) != -1){sb.append((char)len);}return sb.toString();}}public class MainActivity extends Activity {private EditText write;private Button saveButton, readButton;private TextView show;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);show = (TextView) findViewById(R.id.show);write = (EditText) findViewById(R.id.write);saveButton = (Button) findViewById(R.id.save);readButton = (Button) findViewById(R.id.read);final Utils s = new Utils();try {show.setText(s.MyRead());} catch (Exception e1) {// TODO Auto-generated catch blocke1.printStackTrace();} saveButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubtry {s.MyWrite(write.getText().toString());} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}});readButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubtry {show.setText(s.MyRead());} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}});}}

為了讀寫SD卡上的資料，需要添加許可權：


建立於刪除的許可權：
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>


向SD卡中寫入的許可權：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Android---36---讀取SD卡內容