[英]Empty value of EditText
我正在制作一個旨在將長度轉換為不同單位的應用程序。 假設您要將2米轉換為厘米。 您必須在EditText中輸入值,其inputType為numberDecimal,然后在微調器中選擇米,然后在另一個微調器中選擇將其轉換為厘米。 我想使該應用程序完全自動化,並決定添加一個TextWatcher。 問題是,當您刪除EditText中的所有內容時,它顯然不能乘以或除以零(不是0,什么都沒有)並執行方法,因此使應用程序崩潰。 有什么解決辦法嗎? 我已經嘗試過了,但是仍然崩潰了:
final EditText lengthEntry = (EditText) findViewById(R.id.enterLength);
lengthEntry.addTextChangedListener(new TextWatcher() {
final EditText lengthEntry = (EditText) findViewById(R.id.enterLength);
lengthEntry.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
@Override
public void afterTextChanged(Editable s) {}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (Double.valueOf(lengthEntry.getText().toString()) == ""){} else {
lengthConverter();
}
}
});
這是logcat:
FATAL EXCEPTION: main
Process: n1.theconverter, PID: 5585
java.lang.NumberFormatException: Invalid double: ""
at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.parseDouble(StringToReal.java:267)
at java.lang.Double.parseDouble(Double.java:301)
at java.lang.Double.valueOf(Double.java:338)
at n1.theconverter.MainActivity$3.afterTextChanged(MainActivity.java:87)
at android.widget.TextView.sendAfterTextChanged(TextView.java:8007)
at android.widget.TextView$ChangeWatcher.afterTextChanged(TextView.java:10168)
at android.text.SpannableStringBuilder.sendAfterTextChanged(SpannableStringBuilder.java:1043)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:560)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:225)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:224)
at android.view.inputmethod.BaseInputConnection.deleteSurroundingText(BaseInputConnection.java:244)
at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:389)
at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:78)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
先感謝您 :)
編輯:新logcat:
java.lang.NumberFormatException: Invalid double: ""
at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.parseDouble(StringToReal.java:267)
at java.lang.Double.parseDouble(Double.java:301)
at java.lang.Double.valueOf(Double.java:338)
at n1.theconverter.MainActivity.lengthConverter(MainActivity.java:176)
at n1.theconverter.MainActivity$3.onTextChanged(MainActivity.java:91)
at android.widget.TextView.sendOnTextChanged(TextView.java:7991)
at android.widget.TextView.handleTextChanged(TextView.java:8053)
at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:10157)
at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:1033)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:559)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:225)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:224)
at android.text.method.BaseKeyListener.backspaceOrForwardDelete(BaseKeyListener.java:106)
at android.text.method.BaseKeyListener.backspace(BaseKeyListener.java:51)
at android.text.method.BaseKeyListener.onKeyDown(BaseKeyListener.java:215)
at android.text.method.NumberKeyListener.onKeyDown(NumberKeyListener.java:138)
at android.widget.TextView.doKeyDown(TextView.java:6098)
at android.widget.TextView.onKeyDown(TextView.java:5911)
at android.view.KeyEvent.dispatch(KeyEvent.java:2640)
at android.view.View.dispatchKeyEvent(View.java:9234)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at com.android.internal.policy.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:2395)
at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1727)
at android.app.Activity.dispatchKeyEvent(Activity.java:2725)
at android.support.v7.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:541)
at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallbackBase.dispatchKeyEvent(AppCompatDelegateImplBase.java:319)
at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
at com.android.internal.policy.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:2310)
at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4127)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4089)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3787)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3844)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
at android.view.ViewRootImpl$AsyncInputStage.forwa
04-19 20:38:03.451 6053-6053/n1.theconverter D/AndroidRuntime: Shutting down VM
---------
beginning of crash
04-19 20:38:03.451 6053-6053/n1.theconverter E/AndroidRuntime: FATAL EXCEPTION: main
Process: n1.theconverter, PID: 6053
java.lang.NumberFormatException: Invalid double: ""
at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.parseDouble(StringToReal.java:267)
at java.lang.Double.parseDouble(Double.java:301)
at java.lang.Double.valueOf(Double.java:338)
at n1.theconverter.MainActivity.lengthConverter(MainActivity.java:176)
at n1.theconverter.MainActivity$3.onTextChanged(MainActivity.java:91)
at android.widget.TextView.sendOnTextChanged(TextView.java:7991)
at android.widget.TextView.handleTextChanged(TextView.java:8053)
at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:10157)
at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:1033)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:559)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:225)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:224)
at android.text.method.BaseKeyListener.backspaceOrForwardDelete(BaseKeyListener.java:106)
at android.text.method.BaseKeyListener.backspace(BaseKeyListener.java:51)
at android.text.method.BaseKeyListener.onKeyDown(BaseKeyListener.java:215)
at android.text.method.NumberKeyListener.onKeyDown(NumberKeyListener.java:138)
at android.widget.TextView.doKeyDown(TextView.java:6098)
at android.widget.TextView.onKeyDown(TextView.java:5911)
at android.view.KeyEvent.dispatch(KeyEvent.java:2640)
at android.view.View.dispatchKeyEvent(View.java:9234)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1640)
at com.android.internal.policy.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:2395)
at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1727)
at android.app.Activity.dispatchKeyEvent(Activity.java:2725)
at android.support.v7.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:541)
at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallbackBase.dispatchKeyEvent(AppCompatDelegateImplBase.java:319)
at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
at com.android.internal.policy.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:2310)
at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4127)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4089)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3787)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3844)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3661)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3669)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3642)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3695)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3
java.lang.NumberFormatException:無效的double:“”
您不能將空字符串與Double
值進行比較。 您仍然可以檢查editText
是否具有任何值:如果是,則調用您的計算方法。 嘗試這個:
private EditText lengthEntry; //Declare globally
lengthEntry = (EditText) findViewById(R.id.enterLength);
lengthEntry.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (!lengthEntry.getText().toString().equals("")){
lengthConverter();
}
}
希望這可以幫助。
我將在這里做兩件事:首先確保THE LENGTH>0。第二是檢查以確保它確實是可更改的。 例如,不僅是“-”或“。”。 但是類似-#。#
確保lengthEntry
具有輸入字段的正確ID。 您可以嘗試System.out.println();
查看長度和輸入。
並嘗試通過Doube.parseDouble(lenghtEntry.getText().toString());
解析值Doube.parseDouble(lenghtEntry.getText().toString());
。
遇到同樣的問題,ID不正確。
更改您的條件,您的onTextChange
應該如下所示:
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (s.equals(""){
lengthEntry.setText("0");
} else {
lengthConverter();
}
}
我已經找到解決問題的方法。 if
方法中的布爾值不正確。 這是使用isEmpty()
方法執行此操作的正確方法:
if (lengthEntry.getText().toString().isEmpty()){
tvAnswer.setText("0.0");
} else {
lengthConverter();
}
不管怎么說,還是要謝謝你!
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