我是Android开发的新手。我有两个EditTexts，我试图根据ET2改变ET1的值，并且在打字期间自动根据ET1改变ET2的值。
它们的值之和必须为200.因此，如果我想在ET1中键入56，当我键入5时，ET2应显示195.当我添加6时，ET2应显示144（200 - 56）。当焦点仍然在ET1上时，一切都应该发生。
scoreWe.setOnFocusChangeListener(new View.OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (v.hasFocus()) {
scoreYou.addTextChangedListener(null);
scoreWe.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void afterTextChanged(Editable s) {
int scoreW;
try {
scoreW = Integer.parseInt(scoreWe.getText().toString());
} catch (NumberFormatException e) {
scoreW = 0;
}
int scoreY = 200 - scoreW;
String scY = Integer.toString(scoreY);
scoreYou.setText(scY);
}
});
}
}
});
-
scoreYou.setOnFocusChangeListener(new View.OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (v.hasFocus()) {
scoreWe.addTextChangedListener(null);
scoreYou.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void afterTextChanged(Editable s) {
int scoreY;
try {
scoreY = Integer.parseInt(scoreYou.getText().toString());
} catch (NumberFormatException e) {
scoreY = 0;
}
int scoreW = 200 - scoreY;
String scW = Integer.toString(scoreW);
scoreWe.setText(scW);
}
});
}
}
});
这些是2个OnFocusChangeListeners，在我尝试在任何EditTexts中输入内容后，应用程序立即崩溃。 经度：
09-18 16:50:22.362 17764-17764/com.example.dvido.bela E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.dvido.bela, PID: 17764
java.lang.NullPointerException: Attempt to invoke interface method 'void android.text.TextWatcher.beforeTextChanged(java.lang.CharSequence, int, int, int)' on a null object reference
at android.widget.TextView.sendBeforeTextChanged(TextView.java:7941)
at android.widget.TextView.setText(TextView.java:4242)
at android.widget.TextView.setText(TextView.java:4199)
at android.widget.EditText.setText(EditText.java:84)
at android.widget.TextView.setText(TextView.java:4174)
at com.example.dvido.bela.InputGame$1$1.afterTextChanged(InputGame.java:89)
at android.widget.TextView.sendAfterTextChanged(TextView.java:8007)
at android.widget.TextView$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.replace(SpannableStringBuilder.java:492)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:491)
at android.text.method.NumberKeyListener.onKeyDown(NumberKeyListener.java:121)
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 com.android.internal.policy.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:2395)
at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1727)
at android.app.Activity.dispatchKeyEvent(Activity.java:2725)
at android.support.v7.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:543)
at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:53)
at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallbackBase.dispatchKeyEvent(AppCompatDelegateImplBase.java:312)
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$AsyncInputStage.forward(ViewRootImpl.java:3820)
at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:3981)
at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:2253)
at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:1874)
09-18 16：50：36.917 17764-17764 / com.example.dvido.bela I / Process：发送信号。 PID：17764 SIG：9
答案 0 :(得分：0)
我最好的猜测是由于文本更改后的侦听器同时在两个edittext视图中被调用。
尝试在ET2的焦点上禁用ET1的<body id="final-example" onload="document.my_form.reset();">，反之亦然。做这样的事情
禁用scoreWe textChanged Listener
Text changed listener禁用scoreYou textChanged Listener
scoreYou.setOnFocusChangeListener(new View.OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (v.hasFocus()) {
scoreWe.addTextChangedListener(null); // ADD THIS LINE
scoreYou.addTextChangedListener(new TextWatcher(){}); // Add and Implement this line also
//do rest of your logic
}
}
});