Android SD读写存储数据 JAVA 的方式 不推荐

1. package com.escxh.android.meituan;

2. import java.io.BufferedReader;

3. import java.io.File;

4. import java.io.FileInputStream;

5. import java.io.FileNotFoundException;

6. import java.io.FileOutputStream;

7. import java.io.IOException;

8. import java.io.InputStreamReader;

9. import android.app.Activity;

10. import android.content.Intent;

11. import android.os.Bundle;

12. import android.os.Environment;

13. import android.view.View;

14. import android.view.View.OnClickListener;

15. import android.view.Window;

16. import android.widget.Button;

17. import android.widget.CheckBox;

18. import android.widget.EditText;

19. import android.widget.TextView;

20. import android.widget.Toast;

21. import com.escxh.android.R;

22. import com.escxh.android.DIY.EmailAutoCompleteTextView;

23. import com.escxh.android.utils.Logs;

24. public class LoginActivity extends Activity implements OnClickListener {

25. private TextView mTextView;

26. //登录按钮

27. private Button login;

28. //用户名

29. private EmailAutoCompleteTextView mLogin_user;

30. //密码

1. private EditText mLogin_pass;

1. //跳转意图

2. private Intent intent;

3. //记住密码

4. private CheckBox mIsRemember;

5. @Override

6. protected void onCreate(Bundle savedInstanceState) {

7. super.onCreate(savedInstanceState);

8. requestWindowFeature(Window.FEATURE_NO_TITLE);

9. setContentView(R.layout.activity_login_layout);

10. //初始化View

11. initView();

12. //获取用户名 密码

13. getAccount();

14. }

15. private void getAccount(){

16. //判断SD卡是否可用

17. /*

18. * SD 的状态

19. * MEDIA_UNKNOWN:不能识别sd卡

20. MEDIA_REMOVED:没有sd卡

21. MEDIA_UNMOUNTED:sd卡存在但是没有挂载

22. MEDIA_CHECKING:sd卡正在准备

23. MEDIA_MOUNTED：sd卡已经挂载，可用

24. * 写sd卡需要权限

25. <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

26. * 读sd卡，在4.0之前不需要权限，4.0之后可以设置为需要

27. <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

28. * 使用api获得sd卡的真实路径，部分手机品牌会更改sd卡的路径

29. Environment.getExternalStorageDirectory()

30. */

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

32. File file = new File(Environment.getExternalStorageDirectory(),"info.txt");

33. if(file.exists()){

34. try {

35. FileInputStream fis = new FileInputStream(file);

36. //把字节流转换成字符流

37. BufferedReader br = new BufferedReader(new InputStreamReader(fis));

38. //读取txt文件里的用户名和密码

39. String info = br.readLine();

40. String[] infos =info.split("##");

41. mLogin_user.setText(infos[0]);

42. mLogin_pass.setText(infos[1]);

43. } catch (FileNotFoundException e) {

44. e.printStackTrace();

45. } catch (IOException e) {

46. e.printStackTrace();

47. }

48. }

49. }

50. }

51. private void initView(){

52. mTextView = (TextView) findViewById(R.id.login_back);

53. login = (Button) findViewById(R.id.login_login);

54. mIsRemember = (CheckBox) findViewById(R.id.login_isRemember);

55. mLogin_user = (EmailAutoCompleteTextView) findViewById(R.id.login_user);

56. mLogin_pass = (EditText) findViewById(R.id.login_pwd);

57. login.setOnClickListener(this);

58. mTextView.setOnClickListener(this);

59. }

60. @Override

61. public void onClick(View v) {

62. switch (v.getId()) {

63. case R.id.login_login:

64. //判断 记住密码 是否被选中

65. if(mIsRemember.isChecked()){

66. /*

67. * 内部存储API

68. * getFilesDir() 返回一个File 其路径是data/data/包名/files

69. * getCacheDir() 返回 一个File 其路径是data/data/包名/cache

70. */

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

72. String info = mLogin_user.getText().toString()+"##" +mLogin_pass.getText().toString();

73. File file = new File(Environment.getExternalStorageDirectory(),"info.txt");

74. FileOutputStream fos;

75. try {

76. fos = new FileOutputStream(file);

77. fos.write(info.getBytes());

78. fos.close();

79. } catch (IOException e) {

80. e.printStackTrace();

81. }

82. }else{

83. setToast("sd卡不可用哟亲么么哒");

84. }

85. }

86. setToast("登陆成功");

87. intent = new Intent(LoginActivity.this, MeiTuanMainActivity.class);

88. startActivity(intent);

89. break;

90. case R.id.login_back:

91. intent = new Intent(LoginActivity.this, MeiTuanMainActivity.class);

92. startActivity(intent);

93. break;

94. default:

95. break;

96. }

97. }

98. private void setToast(String str){

99. Toast.makeText(this, str, 1000).show();

100. }

101. }