android - 在 Android 中将小数而不是数字添加到 edittext 时应用程序崩溃

Question

我正在创建一个计算器类型的应用程序，它使用 TextWatcher 函数将计算返回到一堆 EditText 字段。我遇到的问题是，当我在数字前输入小数时，我的应用程序崩溃了。这是我目前所拥有的。

public class MainActivity extends ActionBarActivity {

    EditText editText1;
    EditText editText2;
    EditText editText4;
    EditText editText3;
    EditText editText5;
    EditText editText6;
    EditText editText7;
    EditText editText8;
    TextView textViewtotal;
    TextView textViewnet;
    TextView textViewproceeds;
    TextView textViewprof;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText1 = (EditText) findViewById(R.id.editText1);
        editText2 = (EditText) findViewById(R.id.editText2);
        editText3 = (EditText) findViewById(R.id.editText3);
        editText4 = (EditText) findViewById(R.id.editText4);
        editText5 = (EditText) findViewById(R.id.editText5);
        editText6 = (EditText) findViewById(R.id.editText6);
        editText7 = (EditText) findViewById(R.id.editText7);
        editText8 = (EditText) findViewById(R.id.editText8);
        textViewtotal = (TextView) findViewById(R.id.editText6);
        textViewnet = (TextView) findViewById(R.id.editText8);
        textViewproceeds = (TextView) findViewById(R.id.editText7);
        textViewprof = (TextView) findViewById(R.id.editText9);

        editText1.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewproceeds.setText(addProceeds());
                textViewtotal.setText(addTotal());

            }
        });
        editText2.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewtotal.setText(addTotal());
            }
        });
        editText3.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewproceeds.setText(addProceeds());

            }
        });
        editText4.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewtotal.setText(addTotal());
            }
        });
        editText5.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewtotal.setText(addTotal());
            }
        });
        editText6.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewnet.setText(addNet());
                textViewprof.setText(addProfpercent());
            }
        });
        editText7.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewnet.setText(addNet());
            }
        });
        editText8.addTextChangedListener(new TextWatcher() {

            public void beforeTextChanged(CharSequence s, int start, int count,
                                          int after) {
                // TODO Auto-generated method stub

            }

            public void onTextChanged(CharSequence s, int start, int before,
                                      int count) {


            }

            public void afterTextChanged(Editable s) {
                // TODO Auto-generated method stub
                textViewprof.setText(addProfpercent());
            }
        });
    }

    private String addProceeds() {
        Double num1;
        Double num2;

        if(editText1.getText().toString() != "" && editText1.getText().length() > 0) {
            num1 = Double.parseDouble(editText1.getText().toString());
        } else {
            num1 = Double.valueOf(0);
        }
        if(editText3.getText().toString() != "" && editText3.getText().length() > 0) {
            num2 = Double.parseDouble(editText3.getText().toString());
        } else {
            num2 = Double.valueOf(0);
        }

        return Double.toString(num1 * num2);
    }

    private String addTotal() {
        Double num1;
        Double num2;
        Double num3;
        Double num4;

        if (editText1.getText().toString() != "" && editText1.getText().length() > 0) {
            num1 = Double.parseDouble(editText1.getText().toString());
        } else {
            num1 = Double.valueOf(0);
        }
        if (editText2.getText().toString() != "" && editText2.getText().length() > 0) {
            num2 = Double.parseDouble(editText2.getText().toString());
        } else {
            num2 = Double.valueOf(0);
        }
        if (editText4.getText().toString() != "" && editText4.getText().length() > 0) {
            num3 = Double.parseDouble(editText4.getText().toString());
        } else {
            num3 = Double.valueOf(0);
        }
        if (editText5.getText().toString() != "" && editText5.getText().length() > 0) {
            num4 = Double.parseDouble(editText5.getText().toString());
        } else {
            num4 = Double.valueOf(0);
        }

        return Double.toString((num1 * num2) + num3 + num4);
    }

    private String addNet() {
        Double num1;
        Double num2;

        if(editText6.getText().toString() != "" && editText6.getText().length() > 0) {
            num1 = Double.parseDouble(editText6.getText().toString());
            } else {
            num1 = Double.valueOf(0);
            }
        if(editText7.getText().toString() != "" && editText7.getText().length() > 0) {
            num2 = Double.parseDouble(editText7.getText().toString());
            } else {
            num2 = Double.valueOf(0);
            }

        return Double.toString(num2 - num1);
    }



    private String addProfpercent() {
        Double num1;
        Double num2;

        if(editText6.getText().toString() != "" && editText6.getText().length() > 0) {
            num1 = Double.parseDouble(editText6.getText().toString());
        } else {
            num1 = Double.valueOf(0);
        }
        if(editText8.getText().toString() != "" && editText8.getText().length() > 0) {
            num2 = Double.parseDouble(editText8.getText().toString());
        } else {
            num2 = Double.valueOf(0);
        }
        return Double.toString((num2 / num1) * 100);
    }

这是 xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Number of Shares"
        android:id="@+id/textNumShares"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="50dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Initial Share Price"
        android:id="@+id/textInitialPrice"
        android:layout_below="@+id/textNumShares"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="number"
        android:ems="10"
        android:id="@+id/editText1"
        android:layout_alignBottom="@+id/textNumShares"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="false"
        android:maxLength="8"
        android:gravity="right"
        android:width="100dp"/>

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText2"
        android:layout_alignBottom="@+id/textInitialPrice"
        android:layout_alignRight="@+id/editText1"
        android:layout_alignEnd="@+id/editText1"
        android:maxLength="8"
        android:gravity="right"
        android:width="100dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Target/Current Share Price"
        android:id="@+id/textTargetPrice"
        android:layout_below="@+id/textInitialPrice"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText3"
        android:layout_alignBottom="@+id/textTargetPrice"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:maxLength="8"
        android:gravity="right"
        android:width="100dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Brokerage Buy Fee(s)"
        android:id="@+id/textBuyFee"
        android:layout_below="@+id/textTargetPrice"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText4"
        android:layout_alignBottom="@+id/textBuyFee"
        android:layout_alignRight="@+id/editText3"
        android:layout_alignEnd="@+id/editText3"
        android:maxLength="5"
        android:gravity="right"
        android:width="100dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Brokerage Sell Fee(s)"
        android:id="@+id/textSellFee"
        android:layout_below="@+id/textBuyFee"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText5"
        android:layout_alignBottom="@+id/textSellFee"
        android:layout_alignRight="@+id/editText4"
        android:layout_alignEnd="@+id/editText4"
        android:maxLength="5"
        android:gravity="right"
        android:width="100dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Total Purchase Cost"
        android:id="@+id/textTotalCost"
        android:layout_below="@+id/textSellFee"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText6"
        android:layout_alignBottom="@+id/textTotalCost"
        android:layout_alignLeft="@+id/editText5"
        android:layout_alignStart="@+id/editText5"
        android:maxLength="8"
        android:gravity="right"
        android:width="100dp"
        android:editable="false"
        android:clickable="false"
        android:cursorVisible="false"
        android:focusable="false"
        android:longClickable="false"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Proceeds"
        android:id="@+id/textProceeds"
        android:layout_below="@+id/textTotalCost"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText7"
        android:layout_alignBottom="@+id/textProceeds"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:maxLength="8"
        android:gravity="right"
        android:width="100dp"
        android:editable="false"
        android:clickable="false"
        android:cursorVisible="false"
        android:focusable="false"
        android:longClickable="false"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Net Profit"
        android:id="@+id/textNetProfit"
        android:layout_below="@+id/textProceeds"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText8"
        android:layout_alignBottom="@+id/textNetProfit"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:maxLength="8"
        android:gravity="right"
        android:width="100dp"
        android:editable="false"
        android:clickable="false"
        android:cursorVisible="false"
        android:focusable="false"
        android:longClickable="false"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="Return on Investment"
        android:id="@+id/textReturn"
        android:layout_below="@+id/textNetProfit"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="10dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="numberDecimal"
        android:ems="10"
        android:id="@+id/editText9"
        android:layout_alignBottom="@+id/textReturn"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:maxLength="2"
        android:gravity="right"
        android:width="100dp"
        android:editable="false"
        android:clickable="false"
        android:cursorVisible="false"
        android:focusable="false"
        android:longClickable="false"/>

    <EditText
        android:layout_width="wrap_content"
        android:inputType="numberDecimal"
        android:layout_height="wrap_content"
        android:id="@+id/editTest1"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:layout_marginBottom="44dp"
        android:width="100dp"/>

</RelativeLayout>

这是日志

04-05 16:24:42.960 1970-1970/com.example.admin.stockcalcdemo D/AndroidRuntime﹕ Shutting down VM 04-05 16:24:42.960 1970-1970/com.example.admin.stockcalcdemo W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb2fae288) 04-05 16:24:42.960 1970-1970/com.example.admin.stockcalcdemo E/AndroidRuntime﹕ FATAL EXCEPTION: main java.lang.NumberFormatException: Invalid double: "" at java.lang.StringToReal.invalidReal(StringToReal.java:63) at java.lang.StringToReal.initialParse(StringToReal.java:163) at java.lang.StringToReal.parseDouble(StringToReal.java:263) at java.lang.Double.parseDouble(Double.java:295) at com.example.admin.stockcalcdemo.MainActivity.addTotal(MainActivity.java:239) at com.example.admin.stockcalcdemo.MainActivity.access$100(MainActivity.java:16) at com.example.admin.stockcalcdemo.MainActivity$2.afterTextChanged(MainActivity.java:88) at android.widget.TextView.sendAfterTextChanged(TextView.java:7095) at android.widget.TextView$ChangeWatcher.afterTextChanged(TextView.java:8743) at android.text.SpannableStringBuilder.sendAfterTextChanged(SpannableStringBuilder.java:970) at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:497) at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:435) at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:30) at android.view.inputmethod.BaseInputConnection.replaceText(BaseInputConnection.java:672) at android.view.inputmethod.BaseInputConnection.commitText(BaseInputConnection.java:196) at com.android.internal.widget.EditableInputConnection.commitText(EditableInputConnection.java:183) at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:279) at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:77) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:4745) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) at dalvik.system.NativeStart.main(Native Method)

感谢您的帮助。

Answer 1

试试这个，

你必须用 "0"插入小数点，而不仅仅是 ".".或者您也可以通过添加“0”以编程方式解决此问题。按如下方式更新您的代码，

double num2 = Double.parseDouble("0" + editText2.getText().toString());

对接受小数的所有编辑文本执行相同的操作。