保存文件到手机内存

1.编写布局文件

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="亲输入用户名" />

<EditText

android:id="@+id/et_username"

android:layout_width="match_parent"

android:layout_height="wrap_content" >

<requestFocus />

</EditText>

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="亲输入密码" />

<EditText

android:id="@+id/et_password"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:inputType="textPassword" />

<RelativeLayout

android:layout_width="wrap_content"

android:layout_height="wrap_content" >

<CheckBox

android:id="@+id/cb_remember_psw"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:checked="true"

android:text="记住密码" />

<Button

android:onClick="login"

android:layout_alignParentRight="true"

android:id="@+id/login"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="登录" />

</RelativeLayout>

</LinearLayout>

2.编写Activity

public class LoginUIActivity extends Activity {

private EditText et_username = null;

private EditText et_password = null;

private CheckBox cb_remeber_password = null;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

this.et_username = (EditText) this.findViewById(R.id.et_username);

this.et_password = (EditText) this.findViewById(R.id.et_password);

this.cb_remeber_password = (CheckBox) this

.findViewById(R.id.cb_remember_psw);

HashMap<String, String> info = LoginService.getInfo(this);

if(info != null) {

this.et_username.setText(info.get("username"));

this.et_password.setText(info.get("password"));

}

}

public void login(View view) {

String username = this.et_username.getText().toString().trim();

String password = this.et_password.getText().toString().trim();

if (TextUtils.isEmpty(username) || TextUtils.isEmpty(password)) {

Toast.makeText(this, "用户名或密码不能为空", 0).show();

} else {

if (this.cb_remeber_password.isChecked()) {

boolean result = LoginService.saveInfo(this, username, password);

if(result) {

Toast.makeText(this, "保存密码成功", 0).show();

}

}

if ("weijie".equals(username) && "123".equals(password)) {

Toast.makeText(this, "登录成功", 0).show();

} else {

Toast.makeText(this, "登录失败", 0).show();

}

}

}

}

3.编写业务类

public class LoginService {

public static boolean saveInfo(Context context, String username,

String password) {

//getFileDir : /data/data/包名/files

//getCacheDir : /data/data/包名/cache

File file = new File(context.getFilesDir(), "info.txt");

try {

FileOutputStream fos = new FileOutputStream(file);

fos.write((username + "=" + password).getBytes());

fos.flush();

fos.close();

return true;

} catch (Exception e) {

e.printStackTrace();

return false;

}

}

public static HashMap<String, String> getInfo(Context context) {

File file = new File(context.getFilesDir(), "info.txt");

try {

FileInputStream fis = new FileInputStream(file);

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

String[] result = br.readLine().split("=");

HashMap<String, String> map = new HashMap<String, String>();

map.put("username", result[0]);

map.put("password", result[1]);

br.close();

return map;

} catch (Exception e) {

Toast.makeText(context, "无法读取用户信息", 0).show();

}

return null;

}

}