android(6)(读数据的一些权限)

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读数据的权限：public class MainActivity extends Activity implements OnClickListener {    private String basicPath = "/data/data/com.itheima.writedata/files/";    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        findViewById(R.id.btn_read_private).setOnClickListener(this);        findViewById(R.id.btn_write_private).setOnClickListener(this);        findViewById(R.id.btn_read_readable).setOnClickListener(this);        findViewById(R.id.btn_write_readable).setOnClickListener(this);        findViewById(R.id.btn_read_writeable).setOnClickListener(this);        findViewById(R.id.btn_write_writeable).setOnClickListener(this);        findViewById(R.id.btn_read_readable_writeable).setOnClickListener(this);        findViewById(R.id.btn_write_readable_writeable).setOnClickListener(this);    }    /**     * 哪一个控件被点击, v对象就代表被点击的对象     */    @Override    public void onClick(View v) {        switch (v.getId()) {        case R.id.btn_read_private:            readFile("private.txt");            break;        case R.id.btn_write_private:            writeFile("private.txt");            break;        case R.id.btn_read_readable:            readFile("readable.txt");            break;        case R.id.btn_write_readable:            writeFile("readable.txt");            break;        case R.id.btn_read_writeable:            readFile("writeable.txt");            break;        case R.id.btn_write_writeable:            writeFile("writeable.txt");            break;        case R.id.btn_read_readable_writeable:            readFile("readable_writeable.txt");            break;        case R.id.btn_write_readable_writeable:            writeFile("readable_writeable.txt");            break;        default:            break;        }    }    /**     * 读文件     * @param fileName     */    private void readFile(String fileName) {        try {            String path = basicPath + fileName;            BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(path)));            String text = reader.readLine();            reader.close();            Toast.makeText(this, "读取成功: " + text, 0).show();        } catch (Exception e) {            e.printStackTrace();            Toast.makeText(this, "读取失败: " + fileName, 0).show();        }    }    /**     * 写文件     * @param fileName     */    private void writeFile(String fileName) {        try {            String path = basicPath + fileName;            FileOutputStream fos = new FileOutputStream(path);            fos.write("哈哈, 被我给黑了".getBytes());            fos.flush();            fos.close();            Toast.makeText(this, "写入成功: " + fileName, 0).show();        } catch (Exception e) {            e.printStackTrace();            Toast.makeText(this, "写入失败: " + fileName, 0).show();        }    }2.Linux权限：- --- --- ---总共十位，第一位：代表文件类型（d:文件夹；-：文件；l：挂载某一个文件）    第2-4位：rw-：代表的是当前用户的权限。110=6.    第5-7位：当前用户所在组的其他组员的权限     第8-10位：其他所有的权限 ---没有任何权限，r--可读，-w-可写，rw-可读可写。    改变某一个文件的权限：change mode = chmod              chmod 666 private.txt
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