int in = Integer.valueOf(et.getText().toString());
//or
int in2 = new Integer(et.getText().toString());

你应该将String转换为float。它正在起作用。

float result = 0;
 if (TextUtils.isEmpty(et.getText().toString()) {
  return;
}

result = Float.parseFloat(et.getText().toString());

tv.setText(result); 

将字符串转换为int的最佳方法是:

 EditText et = (EditText) findViewById(R.id.entry1);
 String hello = et.getText().toString();
 int converted=Integer.parseInt(hello);

int in = Integer.valueOf(et.getText().toString());
//or
int in2 = new Integer(et.getText().toString());

使用正则表达式:

int i=Integer.parseInt("hello123".replaceAll("[\\D]",""));
int j=Integer.parseInt("123hello".replaceAll("[\\D]",""));
int k=Integer.parseInt("1h2el3lo".replaceAll("[\\D]",""));

输出:

i=123;
j=123;
k=123;

请参阅Integer类和静态parseInt()方法:

http://developer.android.com/reference/java/lang/Integer.html

Integer.parseInt(et.getText().toString());

你将需要捕捉NumberFormatException，尽管在解析时遇到问题，所以:

int myNum = 0;

try {
    myNum = Integer.parseInt(et.getText().toString());
} catch(NumberFormatException nfe) {
   System.out.println("Could not parse " + nfe);
}