我已经研究了解决这个问题的方法,我对 java 还是很陌生,只是在研究它,我有点想先进入它,然后遇到了问题。我遇到的问题是我想更改我正在制作的这个“提示计算器”输出的小数位数,并且我还希望它使用 $ 符号以货币格式格式化。我的代码在下面我正在使用
public class TipCalculatorActivity extends Activity {
DecimalFormat money = new DecimalFormat("$0.00");
EditText costofmeal, tippercent;
TextView tiptotal, totalbill;
Button calctipbtn;
BigDecimal costNum, percentNum, billNum;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
calctipbtn = (Button) findViewById(R.id.calctipbtn);
costofmeal = (EditText) findViewById(R.id.CostofMeal);
tippercent = (EditText) findViewById(R.id.PercentTipText);
tiptotal = (TextView) findViewById(R.id.tiptotal);
totalbill = (TextView) findViewById(R.id.totalbill);
calctipbtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
costNum = new BigDecimal(costofmeal.getText().toString());
percentNum = new BigDecimal(tippercent.getText().toString());
tiptotal.setText(costNum.multiply(percentNum).toString());
System.out.println(money.format(tiptotal));
costNum = new BigDecimal(costofmeal.getText().toString());
billNum = new BigDecimal(tiptotal.getText().toString());
totalbill.setText(costNum.add(billNum).toString());
System.out.println(money.format(totalbill));
}
});
}
}
我的思维方法基本上是我可以得到方程的输出,然后我可以使用money.format
并调用textview
我使用的,它会将它格式化为DecimalFormat
我所拥有的。相反,当我点击计算按钮时,应用程序强制关闭,我得到的日志错误是
06-04 21:32:57.242: D/AndroidRuntime(1905): Shutting down VM
06-04 21:32:57.242: W/dalvikvm(1905): threadid=1: thread exiting with uncaught exception (group=0x40015578)
06-04 21:32:57.257: E/AndroidRuntime(1905): FATAL EXCEPTION: main
06-04 21:32:57.257: E/AndroidRuntime(1905): java.lang.IllegalArgumentException
06-04 21:32:57.257: E/AndroidRuntime(1905): at java.text.NumberFormat.format(NumberFormat.java:308)
06-04 21:32:57.257: E/AndroidRuntime(1905): at
java.text.DecimalFormat.format(DecimalFormat.java:714)
06-04 21:32:57.257: E/AndroidRuntime(1905): at java.text.Format.format(Format.java:93)
06-04 21:32:57.257: E/AndroidRuntime(1905): at com.verge.tipcalc.TipCalculatorActivity$1.onClick(TipCalculatorActivity.java:50)
06-04 21:32:57.257: E/AndroidRuntime(1905): at android.view.View.performClick(View.java:2537)
06-04 21:32:57.257: E/AndroidRuntime(1905): at android.view.View$PerformClick.run(View.java:9157)
06-04 21:32:57.257: E/AndroidRuntime(1905): at
android.os.Handler.handleCallback(Handler.java:587)
06-04 21:32:57.257: E/AndroidRuntime(1905): at android.os.Handler.dispatchMessage(Handler.java:92)
06-04 21:32:57.257: E/AndroidRuntime(1905): at android.os.Looper.loop(Looper.java:130)
06-04 21:32:57.257: E/AndroidRuntime(1905): at android.app.ActivityThread.main(ActivityThread.java:3687)
06-04 21:32:57.257: E/AndroidRuntime(1905): at java.lang.reflect.Method.invokeNative(Native Method)
06-04 21:32:57.257: E/AndroidRuntime(1905): at java.lang.reflect.Method.invoke(Method.java:507)
06-04 21:32:57.257: E/AndroidRuntime(1905): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
06-04 21:32:57.257: E/AndroidRuntime(1905): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
06-04 21:32:57.257: E/AndroidRuntime(1905): at dalvik.system.NativeStart.main(Native Method)
我想要做的就是将totalbill
和舍入tiptotal
到小数点后 2 位,并将其格式化为我尝试过的 3-4 种方法,但都没有成功。