在共享首选项中设置/放置数值？

Question

public void onClick(View v) {
    switch(v.getId()){
    case R.id.save2:
        s = text.getText().toString();
        number = Float.parseFloat(num.getText().toString());
        SharedPreferences.Editor editor = shared.edit();
        editor.putString("sharedtext",s);
        editor.putFloat("sharednum",number);
        editor.commit();
        Toast.makeText(this,"save2",Toast.LENGTH_SHORT).show();
        break;
    case R.id.load2:
        String returner = shared.getString("sharedtext","Returner fail");
        float returnnum = shared.getFloat("sharednum","number fail");
        //there is a red mark here^^^^^^^^^(getfloat)
        text.setText(returner);
        //num.set.......how will
        Toast.makeText(this,"load2",Toast.LENGTH_SHORT).show();
        break;
    case R.id.page2:
        intent= new Intent(this,SharedPreferencesActivity.class);
        startActivity(intent);
        Toast.makeText(this,"page2",Toast.LENGTH_SHORT).show();
        break;
    }

//这里有一个红色标记^^^^^^^^^(getfloat) - 一个让我切换到getInt和getFloat的错误

//num.set.......我将如何设置一个数字值？

谢谢

Answer 1

当您尝试从首选项中获取值时，您还需要设置一个默认值，如下所示：

float returnnum = shared.getFloat("sharednum",0.0);

Answer 2

试试这个

  float returnnum = shared.getFloat("sharednum",0f);

Answer 3

float returnnum =shared.getFloat("sharednum","numberfail");

将“numberfail”更改为 float 类型的数字。该参数代表默认值，因此不能使用字符串。