我正在尝试创建一个计数器的倒数。每个计时器显示（hh：mm：ss）是由edittexts组成的线性布局。我有一个计数器（用于计数），这是一个只有1个editText的线性布局。我有一个片段，显示2个计时器布局和1个计数器布局。
我的动机是让用户输入总时间和两个值中的一个：每圈的圈数/时间。然后我想使用以下基本方程式计算另一个... timePerLap = totalTime / lapCount。 我有两个单选按钮，一次只能控制一个场的可见性。
现在的问题是：我想进行计算并根据用户输入的值更新radiobuttons的onCheckedChanged（）值。我在自定义布局类中调用一个方法来使用EditText的setText设置值，但它会抛出一个带有以下stackTrace的NPE。我调试并发现editText是NOT NULL。所以这不是问题的原因。
java.lang.NullPointerException
at android.widget.TextView.sendBeforeTextChanged(TextView.java:8850)
at android.widget.TextView.access$1100(TextView.java:282)
at android.widget.TextView$ChangeWatcher.beforeTextChanged(TextView.java:11243)
at android.text.SpannableStringBuilder.sendBeforeTextChanged(SpannableStringBuilder.java:956)
at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:466)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:212)
at android.text.SpannableStringBuilder.delete(SpannableStringBuilder.java:30)
at android.text.method.BaseKeyListener.backspaceOrForwardDelete(BaseKeyListener.java:94)
at android.text.method.BaseKeyListener.backspace(BaseKeyListener.java:49)
at android.text.method.BaseKeyListener.onKeyDown(BaseKeyListener.java:155)
at android.text.method.NumberKeyListener.onKeyDown(NumberKeyListener.java:138)
at android.widget.TextView.doKeyDown(TextView.java:6907)
at android.widget.TextView.onKeyDown(TextView.java:6679)
at android.view.KeyEvent.dispatch(KeyEvent.java:3173)
at android.view.View.dispatchKeyEvent(View.java:7994)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1470)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:2262)
at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1612)
at android.app.Activity.dispatchKeyEvent(Activity.java:2524)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:2181)
at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4665)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4632)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4197)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4251)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4220)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4331)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4228)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4388)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4197)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4251)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4220)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4228)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4197)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6564)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6481)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6452)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6417)
at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3764)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5487)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
主要片段：
public class WorkoutTimerFragment extends Fragment {
TimerLayout mTotalWOTime;
TimerLayout mTimePerRep;
RadioButton mTimePerRepRadio;
RadioButton mRepCountRadio;
Counter mRepCount;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
LinearLayout parentLayout = (LinearLayout) inflater.inflate(R.layout.workout_timer_fragment, container, false);
//All variables are initialized ...
mTimePerRep = (TimerLayout) timePerRepLayout.getChildAt(0);
mTimePerRep.setVisibility(View.INVISIBLE);
mRepCount = (Counter) timePerRepLayout.getChildAt(1);
RadioGroup radioGroupLayout = (RadioGroup) repLayout.getChildAt(1);
mTimePerRepRadio = (RadioButton) radioGroupLayout.getChildAt(0);
mRepCountRadio = (RadioButton) radioGroupLayout.getChildAt(1);
mRepCountRadio.setOnCheckedChangeListener(null);
mRepCountRadio.setChecked(true);
mTimePerRepRadio.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
mTimePerRep.setVisibility(View.VISIBLE);
mRepCount.setVisibility(View.INVISIBLE);
calculateStartTimes();
}
}
});
mRepCountRadio.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
mTimePerRep.setVisibility(View.INVISIBLE);
mRepCount.setVisibility(View.VISIBLE);
}
calculateStartTimes();
}
});
return parentLayout;
}
public void calculateStartTimes() {
long totalWorkoutTime = mTotalWOTime.getTotalMilliseconds();
long timePerRep;
if (totalWorkoutTime > 0) {
if (mRepCount.getCounterValue() > 0) {
mTimePerRep.setTime(totalWorkoutTime / mRepCount.getCounterValue());
} else if ((timePerRep = mTimePerRep.getTotalMilliseconds()) > 0) {
mRepCount.setCounterValue((int) (totalWorkoutTime / timePerRep));
} else {
//TODO AlertDialog showing the user needs to enter some information
}
}
}
}
Counter.java - 在行mCounter.setText（String.valueOf（counterValue））上的setCounterValue（）方法中导致以下问题的布局;
public class Counter extends LinearLayout implements BaseLayout {
private final TextView mCounterHeader;
private final EditText mCounter;
private TextWatcher mTextWatcher;
private BaseLayout.OnItemChangeListener mItemChangedListener;
private View mView;
public Counter(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.Options, 0, 0);
String titleText = a.getString(R.styleable.Options_titleText);
setOrientation(LinearLayout.VERTICAL);
setGravity(Gravity.CENTER_VERTICAL);
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mView = inflater.inflate(R.layout.counter, this, true);
mCounterHeader = (TextView) getChildAt(0);
mCounterHeader.setText(titleText);
mCounter = (EditText) getChildAt(1);
mCounter.setText("0");
mCounter.addTextChangedListener(mTextWatcher);
mTextWatcher = new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence value, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence value, int start, int before, int count) {
//Some Listener call back I want to implement but don't have an implementation for yet.
if (mItemChangedListener != null) {
mItemChangedListener.onItemChanged(Counter.this);
}
}
@Override
public void afterTextChanged(Editable editableValue) {
}
};
}
public int getCounterValue() {
return Integer.parseInt((mCounter.getText().toString()));
}
public void setCounterValue(int counterValue) {
if (counterValue > 0) {
mCounter.setText(String.valueOf(counterValue));
}
}
public void setItemChangedListener(BaseLayout.OnItemChangeListener itemChangedListener) {
mItemChangedListener = itemChangedListener;
}
}
答案 0 :(得分：0)
从上面的代码中，您似乎没有通过调用
初始化自定义侦听器setItem在您的活动中更改了侦听器。请确认这个