Question

我已经研究过如何解决这个问题我仍然是java的新手并且正在研究它并且有点潜入它并遇到问题。我遇到的问题是我想要更改我正在制作的“提示计算器”输出的小数位数，我还希望它使用$符号格式化货币。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等式的输出然后我可以使用money.format并调用我使用的textview并将其格式化为{{1我有。相反，当我点击计算按钮时，app力关闭，我得到的日志错误是

DecimalFormat

我想做的就是围绕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)和totalbill到2位小数并将其格式化为货币我已经尝试了3-4种方法我查了一下而且没有一个是成功的。

Answer 1

你需要这样做 -

DecimalFormat money = new DecimalFormat("00.00");
money.setRoundingMode(RoundingMode.UP);// you can also use DOWN here if you dont need to round up the decimal.
.
.
System.out.println(money.format(new Double(totalbill.getText())));

这里重要的是我认为你错过的是new Double(totalbill.getText())。您无法直接传递totalBill，因为它是textView。您需要将其解析为Double或Flot，然后将其传递给formatter。

此外，$可以附加到文本中。

totalbill.setText("$" + totalbill.getText())

Answer 2

你可以试试这段代码

像这样转换你的BigDecimal值，使其十进制值最多为2个地方

   BigDecimal bd = new BigDecimal( costNum);
   bd = bd.setScale(2, BigDecimal.ROUND_HALF_UP);

在Android开发中使用DecimalFormat

2 个答案: