内部存储空间读写文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/et_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入用户名" />

    <EditText
        android:id="@+id/et_pass"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入密码"
        android:inputType="textPassword" />

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <CheckBox
            android:id="@+id/cb"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:text="记住用户名和密码" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_gravity="right"
            android:onClick="login"
            android:text="登录" />
    </RelativeLayout>

</LinearLayout>

 

 

public class MainActivity extends Activity {

    private EditText et_name;
	private EditText et_pass;

	@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_name = (EditText) findViewById(R.id.et_name);
    	et_pass = (EditText) findViewById(R.id.et_pass);
    	
        readAccount();
        
    }

    public void readAccount(){
//    	File file = new File(getFilesDir(), "info.txt");
    	File file = new File(getCacheDir(), "info.txt");
    	if(file.exists()){
	    	try {
				FileInputStream fis = new FileInputStream(file);
				//把字节流转换成字符流
				BufferedReader br = new BufferedReader(new InputStreamReader(fis));
				//读取txt文件里的用户名和密码
				String text = br.readLine();
				String[] s = text.split("##");
				
		    	et_name.setText(s[0]);
		    	et_pass.setText(s[1]);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
    	}
    }

    public void login(View v){
    	
    	String name = et_name.getText().toString();
    	String pass = et_pass.getText().toString();
    	
    	CheckBox cb = (CheckBox) findViewById(R.id.cb);
    	//判断选框是否被勾选
    	if(cb.isChecked()){
    		//返回一个File对象，其路径是data/data/com.example.apirwinrom/files
//    		File file = new File(getFilesDir(), "info.txt");
    		
    		//返回值也是一个File对象，其路径是data/data/com.example.apirwinrom/cache
    		File file = new File(getCacheDir(), "info.txt");
    		FileOutputStream fos;
			try {
				fos = new FileOutputStream(file);
				fos.write((name + "##" + pass).getBytes());
				fos.close();
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
    	}
    	
    	//创建并显示吐司对话框
    	Toast.makeText(this, "登录成功", 0).show();
    }
    
}