Android之SD卡上的文件读取

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public class ReadSDCard extends Activity {

String FILE_NAME = "/test1.txt" ;//SD卡的文件的路径

Button writeBtn, readBtn ; // 一个写的按钮，一个读取的按钮

EditText text1, text2 ;

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setContentView(R.layout. activity_readsdcard);

writeBtn = (Button) findViewById(R.id.btn_write);

readBtn = (Button) findViewById(R.id.btn_read);

text1 = (EditText) findViewById(R.id.edit_t1);

text2 = (EditText) findViewById(R.id.edit_t2);

writeBtn.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

String msg = text1.getText().toString();

writeMSG(msg);

text1.setText("" );

}

});

readBtn.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

try {

// 如果手机插入了SD卡，而且应用程序具有访问SD的权限(要在配置文件中注册)

if (Environment.getExternalStorageState().equals(Environment. MEDIA_MOUNTED)) {

// 获取SD卡对应的存储目录

File sdCardDir = Environment

. getExternalStorageDirectory();

// 获取指定文件对应的输入流

FileInputStream fis = new FileInputStream(sdCardDir

.getCanonicalFile() + FILE_NAME);

// 将制定的流包装秤BufferedReader

BufferedReader br = new BufferedReader(

new InputStreamReader(fis));

StringBuilder sb = new StringBuilder("" );

String line = null;

// 循环读取文件的内容

while ((line = br.readLine()) != null) {

sb.append(line);

}

br.close();

text2.setText(sb);

}

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

});

}

private void writeMSG(String content) {

try {

if (Environment.getExternalStorageState().equals(Environment. MEDIA_MOUNTED)) {

// 获取SD卡目录

File sdCard = Environment.getExternalStorageDirectory();

File targeFile = new File(sdCard.getCanonicalFile() + FILE_NAME );

// 以指定文件创建RandomAccessFile对象

RandomAccessFile raf = new RandomAccessFile(targeFile, "rw" );

// 将文件记住的指针移动到最后(移到最后才能追加、不然只能覆盖原有的数据)

raf.seek(targeFile.length());

raf.write(content.getBytes());

System. out.println("写入成功" + raf);

raf.close();

}

} catch (Exception e) {

}

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