Android基础学习之SharedPreferences

SharedPreferences，可以储存程序少量的数据，默认写在私有目录下，不和外部程序共享。
1.xml布局，添加两个EditText和两个Button,模拟写入和读取。
2.java部分

public class MainActivity extends Activity implements OnClickListener{
    private static final String FILENAME = "myfile";//文件名
    EditText edit1, edit2;
    SharedPreferences sp;//sp对象
    int i;
    private Button button1;
    private Button button2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.face);
        edit1 = (EditText) findViewById(R.id.editText1);
        edit2 = (EditText) findViewById(R.id.editText2);
        button1 = (Button) findViewById(R.id.button1);
        button2 = (Button) findViewById(R.id.button2);
        button1.setOnClickListener(this);
        button2.setOnClickListener(this);
        sp = this.getSharedPreferences(FILENAME, Context.MODE_WORLD_READABLE
                + Context.MODE_WORLD_WRITEABLE);//获取活动的sp对象

    }

    private void writeData(String string) {
        SharedPreferences.Editor editor = sp.edit();//获取编辑对象
        editor.putString("key" + i, string + i);//键值对写入方式
        editor.commit();//提交
        i++;
    }

    private CharSequence readData() {
        String s = sp.getString("key1", "no data");//读取

        Map<String, String> maps = (Map<String, String>) sp.getAll();
        Log.e("key" + i, maps.get("key" + i));
        i++;

        return s;
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.button1:
            edit1.setText(readData());
            break;
        case R.id.button2:
            writeData(edit2.getText().toString());
            break;
        default:
            break;
        }
    }
}

其实就简单的三步：获取sp流对象，获取编辑对象，写入读出。