android .txt文件的写入，读取，还有复制图片

txt文件的写入：

private void save() {
        FileOutputStream fos = null;
        String state = Environment.getExternalStorageState();// sd状态
        if (state.equals(Environment.MEDIA_MOUNTED)) {// 判断sd卡是否可用
            File root = Environment.getExternalStorageDirectory();
            File targeDir = new File(root, super.getPackageName());// 要把文件写相应在activity下

            if (!targeDir.exists()) {// 判断目录是否存在
                targeDir.mkdir();// 创建
            }
            // String newFile=file.toString()+"/"+"user.txt";
            // IO操作
            // 流
            try {
                // 括号里是路径
                fos = new FileOutputStream(new File(targeDir, "userinfo.txt"));// 输出流
                String content = name;
                /*
                 * for(int i=0;i<content.length();i++){
                 * fos.write(content.charAt(i));//一个个字节输 }
                 */
                byte[] data = content.getBytes();
                fos.write(data);

            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // 输入输出都会引发IO异常
                e.printStackTrace();
            } finally {
                // 打开流就需要关闭
                try {
                    fos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }

        }
    }

txt文件的读取：

private void read() {
        FileInputStream fis = null;
        String state = Environment.getExternalStorageState();
        if (state.equals(Environment.MEDIA_MOUNTED)) {
            File root = Environment.getExternalStorageDirectory();
            File file = new File(root, super.getPackageName() + "/userinfo.txt");
            if (file.exists()) {
                try {
                    fis = new FileInputStream(file);
                    int len = 0;
                    StringBuilder builder = new StringBuilder();
                    byte[] buffer = new byte[1024];

                    while ((len = fis.read(buffer)) != -1) {
                        builder.append(new String(buffer, 0, len));
                        // builder.append(buffer);//乱码
                    }
                    /*
                     * while((len=fis.read())!=-1){ builder.append((char)len); }
                     */
                    Toast.makeText(getApplicationContext(), builder.toString(),
                            Toast.LENGTH_SHORT).show();
                    text2.setText(builder.toString());

                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    Log.i("read", e.getMessage());
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } finally {
                    try {
                        fis.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        }
    }

图片的复制：

先在assets文件夹下建一个image文件夹，里面放一张图片

private void copy() {
        FileOutputStream output = null;
        InputStream source = null;
        String state = Environment.getExternalStorageState();
        if (state.equals(Environment.MEDIA_MOUNTED)) {
            // inputstream=super.getResources().openRawResource(R.drawable.ic_launcher);

            try {
                AssetManager manager = super.getAssets();
                source = manager.open("image/ic_launcher.png");
                File target = new File(
                        Environment.getExternalStorageDirectory() + "/"
                                + super.getPackageName() + "/mycopyimg.png");
                output = new FileOutputStream(target);

                int len = 0;
                byte[] buffer = new byte[1024];
                while ((len = source.read(buffer)) != -1) {
                    output.write(buffer, 0, len);
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                Log.i("111", e.getMessage());
            } finally {
                try {
                    source.close();
                    output.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }