我试图创建一个可以满足我的需求的 NumberPicker，但我偶然发现了一些东西，但我不明白它是什么。
行为很简单，我有三个数字选择器，每个数字选择器的值可以从 -15 到 15 之间；当用户按下Ok按钮选择的值（如果有效）将保存在“结构”和 SharedPreferences 中，以方便使用。
问题如图所示这个截图.
当我保存一个不是 -1 的数字时，它可以正常工作。如果我保存 -1，结果就是上面的结果（它发生在每个数字选择器中）。
即使显示 -15，存储的实际值是 -1：在 -15 之上和之下，值是正确的，如果我滑动一个像素，值将变为 -1，在 OnClick 中解析的值是 -1和返回的值
value < 0 ? value + maxValue + 1 : value - 1
setPickers() 中的内容是正确的（29，数组的最后一个索引）。
我尝试将各种初始化移动到代码的不同部分，并使其在三个设备上运行；两个物理版本（使用 Android 5.0.2 和 5.1.1）和一个使用 Android Studio 模拟的版本（使用 KitKat 映像），但问题始终存在。
现在我开始认为我要么错过了一些真正基本的东西，要么恰恰相反。
感谢您的任何帮助，您可以提供。
.java：
public class CoefficientsDialog extends DialogFragment {
private Activity activity;
private MyView myView;
private AlertDialog alertDialog;
private AlertDialog.Builder builder;
private NumberPicker startPicker, endPicker, stepPicker;
final private String C = "C_Coefficient";
final private String Gamma = "Gamma_Coefficient";
private String cStartKey;
private String cEndKey;
private String cStepKey;
private String gStartKey;
private String gEndKey;
private String gStepKey;
String[] defaultValues = new String[]{
"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11",
"12", "13", "14", "15", "-15", "-14", "-13", "-12", "-11",
"-10", "-9", "-8", "-7", "-6", "-5", "-4", "-3", "-2", "-1"
};
final int minValue = 0;
final int maxValue = defaultValues.length - 1;
private SharedPreferences settings;
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final String tag = getTag();
cStartKey = getString(R.string.c_start_key);
cEndKey = getString(R.string.c_end_key);
cStepKey = getString(R.string.c_step_key);
gStartKey = getString(R.string.g_start_key);
gEndKey = getString(R.string.g_end_key);
gStepKey = getString(R.string.g_step_key);
activity = getActivity();
settings = PreferenceManager.getDefaultSharedPreferences(activity);
builder = new AlertDialog.Builder(activity);
myView = new MyView(activity);
setPickers();
switch (tag) {
case (C):
String cTitle = "C coefficient range";
init(cTitle, tag);
break;
case (Gamma):
String gTitle = "Gamma coefficient range";
init(gTitle, tag);
break;
default:
dismiss();
break;
}
return alertDialog;
}
private void init(String title, final String tag) {
builder
.setView(myView)
.setTitle(title)
.setPositiveButton("Ok", null)
.setNegativeButton("Back", null);
alertDialog = builder.create();
alertDialog.setOnShowListener(new DialogInterface.OnShowListener() {
@Override
public void onShow(final DialogInterface dialog) {
Button button = alertDialog.getButton(AlertDialog.BUTTON_POSITIVE);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int start = startPicker.getValue();
int end = endPicker.getValue();
int step = stepPicker.getValue();
int middle = defaultValues.length / 2;
// The index is different from the actual value, method valid only if the
// array is antisymmetric
start = start <= middle ? start + 1 : start - maxValue - 1;
end = end <= middle ? end + 1 : end - maxValue - 1;
step = step <= middle ? step + 1 : step - maxValue - 1;
// If true, the user is trying to go from a positive value to a negative
// value with a positive step or vice versa
if ((end - start) / step < 0)
Toast.makeText(activity, R.string.wrong_direction, Toast.LENGTH_SHORT)
.show();
// If true, start + (n * step) isn't equal to end given any value of n
else if ((end - start) % step != 0)
Toast.makeText(activity, R.string.step_inadequate, Toast.LENGTH_SHORT)
.show();
else if (end == start)
Toast.makeText(activity, R.string.one_value_validation,
Toast.LENGTH_SHORT)
.show();
else {
savePreferences(tag, start, end, step);
alertDialog.dismiss();
}
}
});
}
});
}
private void savePreferences(final String tag, int start, int end, int step) {
SharedPreferences.Editor editor = settings.edit();
switch (tag) {
case (C): {
ModelingStructure.cStart = start;
ModelingStructure.cEnd = end;
ModelingStructure.cStep = step;
editor.putInt(cStartKey, start);
editor.putInt(cEndKey, end);
editor.putInt(cStepKey, step);
editor.apply();
break;
}
case (Gamma): {
ModelingStructure.gStart = start;
ModelingStructure.gEnd = end;
ModelingStructure.gStep = step;
editor.putInt(gStartKey, start);
editor.putInt(gEndKey, end);
editor.putInt(gStepKey, step);
editor.apply();
break;
}
}
}
private void setPickers() {
// Initialize startPicker
startPicker = (NumberPicker) myView.findViewById(R.id.cStartPicker);
startPicker.setMaxValue(maxValue);
startPicker.setMinValue(minValue);
startPicker.setDisplayedValues(defaultValues);
// Initialize endPicker
endPicker = (NumberPicker) myView.findViewById(R.id.cEndPicker);
endPicker.setMinValue(minValue);
endPicker.setMaxValue(maxValue);
endPicker.setDisplayedValues(defaultValues);
// Initialize stepPicker
stepPicker = (NumberPicker) myView.findViewById(R.id.cStepPicker);
stepPicker.setMinValue(minValue);
stepPicker.setMaxValue(maxValue);
stepPicker.setDisplayedValues(defaultValues);
// Check if the pickers were previously changed
int start = settings.getInt(cStartKey, 1);
int end = settings.getInt(cEndKey, 1);
int step = settings.getInt(cStepKey, 1);
// The index is different from the actual value
startPicker.setValue(start < 0 ? start + maxValue + 1 : start - 1);
endPicker.setValue (end < 0 ? end + maxValue + 1 : end - 1);
stepPicker.setValue (step < 0 ? step + maxValue + 1 : step - 1);
}
public void showDialog() {
alertDialog.show();
}
[...]
}
.xml：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/c_start"
android:id="@+id/cStartView"
android:layout_alignStart="@+id/cStartPicker"
android:layout_alignEnd="@+id/cStartPicker"
android:gravity="center_horizontal" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/c_end"
android:id="@+id/cEndView"
android:layout_alignStart="@+id/cEndPicker"
android:layout_alignEnd="@+id/cEndPicker"
android:gravity="center_horizontal" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/c_step"
android:id="@+id/cStepView"
android:gravity="center_horizontal"
android:layout_alignStart="@+id/cStepPicker"
android:layout_alignEnd="@+id/cStepPicker" />
<NumberPicker
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/cEndPicker"
android:layout_centerInParent="true" />
<NumberPicker
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/cStartPicker"
android:layout_centerInParent="true"
android:layout_toStartOf="@id/cEndPicker"
android:layout_marginEnd="10dp" />
<NumberPicker
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/cStepPicker"
android:layout_centerInParent="true"
android:layout_toEndOf="@id/cEndPicker"
android:layout_marginStart="10dp" />
</RelativeLayout>
