将日历添加到 PreferenceScreen

Question

我正在使用 DatePreference.java class 作为我的 xml 文件中的首选项。问题是我得到一个错误：Binary XML file line #496: Error inflating class com.fsck.k9.ui.settings.account.DatePreference 请注意，第 496 行是我发布的 xml 代码的第一行。

如果不建议另一种将日历添加到 PreferenceScreen 的方法，也会有所帮助。谢谢

package com.fsck.k9.ui.settings.account;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.preference.DialogPreference;
import android.util.AttributeSet;
import android.view.View;
import android.widget.DatePicker;

public class DatePreference extends DialogPreference {
    private int lastDate = 0;
    private int lastMonth = 0;
    private int lastYear = 0;
    private String dateval;
    private CharSequence mSummary;
    private DatePicker picker = null;
    public static int getYear(String dateval) {
        String[] pieces = dateval.split("-");
        return (Integer.parseInt(pieces[0]));
    }

    public static int getMonth(String dateval) {
        String[] pieces = dateval.split("-");
        return (Integer.parseInt(pieces[1]));
    }

    public static int getDate(String dateval) {
        String[] pieces = dateval.split("-");
        return (Integer.parseInt(pieces[2]));
    }

    public DatePreference(Context ctxt, AttributeSet attrs) {
        super(ctxt, attrs);

        setPositiveButtonText("Set");
        setNegativeButtonText("Cancel");
    }

    @Override
    protected View onCreateDialogView() {
        picker = new DatePicker(getContext());

        // setCalendarViewShown(false) attribute is only available from API level 11
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            picker.setCalendarViewShown(false);
        }

        return (picker);
    }

    @Override
    protected void onBindDialogView(View v) {
        super.onBindDialogView(v);

        picker.updateDate(lastYear, lastMonth + 1, lastDate);
    }

    @Override
    protected void onDialogClosed(boolean positiveResult) {
        super.onDialogClosed(positiveResult);

        if (positiveResult) {
            lastYear = picker.getYear();
            lastMonth = picker.getMonth();
            lastDate = picker.getDayOfMonth();

            String dateval = String.valueOf(lastYear) + "-"
                    + String.valueOf(lastMonth) + "-"
                    + String.valueOf(lastDate);

            if (callChangeListener(dateval)) {
                persistString(dateval);
            }
        }
    }

    @Override
    protected Object onGetDefaultValue(TypedArray a, int index) {
        return (a.getString(index));
    }

    @Override
    protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
        dateval = null;

        if (restoreValue) {
            if (defaultValue == null) {
                Calendar cal = Calendar.getInstance();
                SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
                String formatted = format1.format(cal.getTime());
                dateval = getPersistedString(formatted);
            } else {
                dateval = getPersistedString(defaultValue.toString());
            }
        } else {
            dateval = defaultValue.toString();
        }
        lastYear = getYear(dateval);
        lastMonth = getMonth(dateval);
        lastDate = getDate(dateval);
    }

    public void setText(String text) {
        final boolean wasBlocking = shouldDisableDependents();

        dateval = text;

        persistString(text);

        final boolean isBlocking = shouldDisableDependents();
        if (isBlocking != wasBlocking) {
            notifyDependencyChange(isBlocking);
        }
    }

    public String getText() {
        return dateval;
    }

    public CharSequence getSummary() {
        return mSummary;
    }

    public void setSummary(CharSequence summary) {
        if (summary == null && mSummary != null || summary != null
                && !summary.equals(mSummary)) {
            mSummary = summary;
            notifyChanged();
        }
    }
}

在 xml 部分我提到了 DatePreference

  <com.fsck.k9.ui.settings.account.DatePreference
            android:key="keyname"
            android:title="Enter start date"
            android:defaultValue="2014-08-01"
            android:summary="Summary"/>

详细错误

android.view.InflateException: Binary XML file line #496: Error inflating class com.fsck.k9.ui.settings.account.DatePreference
            at android.support.v7.preference.PreferenceInflater.createItem(PreferenceInflater.java:258)
            at android.support.v7.preference.PreferenceInflater.createItemFromTag(PreferenceInflater.java:287)
            at android.support.v7.preference.PreferenceInflater.rInflate(PreferenceInflater.java:354)
            at android.support.v7.preference.PreferenceInflater.rInflate(PreferenceInflater.java:356)
            at android.support.v7.preference.PreferenceInflater.inflate(PreferenceInflater.java:162)
            at android.support.v7.preference.PreferenceInflater.inflate(PreferenceInflater.java:112)
            at android.support.v7.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:137)
            at android.support.v7.preference.PreferenceManagerFix.inflateFromResource(PreferenceManagerFix.java:58)
            at android.support.v7.preference.PreferenceFragmentCompat.setPreferencesFromResource(PreferenceFragmentCompat.java:448)
            at com.fsck.k9.ui.settings.account.AccountSettingsFragment.onCreatePreferencesFix(AccountSettingsFragment.kt:53)
            at com.takisoft.fix.support.v7.preference.PreferenceFragmentCompat.onCreate(PreferenceFragmentCompat.java:62)
            at android.support.v4.app.Fragment.performCreate(Fragment.java:2331)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1386)
            at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1188)
            at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:1071)
            at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:115)
            at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2380)
            at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2338)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2245)
            at android.support.v4.app.FragmentManagerImpl.run(FragmentManager.java:703)
            at android.os.Handler.handleCallback(Handler.java:873)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:193)
            at android.app.ActivityThread.main(ActivityThread.java:6669)
            at java.lang.reflect.Method.invoke(Native Method)
            at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
         Caused by: java.lang.ClassCastException: com.fsck.k9.ui.settings.account.DatePreference cannot be cast to android.support.v7.preference.Preference
            at android.support.v7.preference.PreferenceInflater.createItem(PreferenceInflater.java:251)
            at android.support.v7.preference.PreferenceInflater.createItemFromTag(PreferenceInflater.java:287) 
            at android.support.v7.preference.PreferenceInflater.rInflate(PreferenceInflater.java:354) 
            at android.support.v7.preference.PreferenceInflater.rInflate(PreferenceInflater.java:356) 
            at android.support.v7.preference.PreferenceInflater.inflate(PreferenceInflater.java:162) 
            at android.support.v7.preference.PreferenceInflater.inflate(PreferenceInflater.java:112) 
            at android.support.v7.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:137) 
            at android.support.v7.preference.PreferenceManagerFix.inflateFromResource(PreferenceManagerFix.java:58) 
            at android.support.v7.preference.PreferenceFragmentCompat.setPreferencesFromResource(PreferenceFragmentCompat.java:448) 
            at com.fsck.k9.ui.settings.account.AccountSettingsFragment.onCreatePreferencesFix(AccountSettingsFragment.kt:53) 
            at com.takisoft.fix.support.v7.preference.PreferenceFragmentCompat.onCreate(PreferenceFragmentCompat.java:62) 
            at android.support.v4.app.Fragment.performCreate(Fragment.java:2331) 
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1386) 
            at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1188) 
            at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:1071) 
            at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:115) 
            at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2380) 
            at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2338) 
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2245) 
            at android.support.v4.app.FragmentManagerImpl.run(FragmentManager.java:703) 
            at android.os.Handler.handleCallback(Handler.java:873) 
            at android.os.Handler.dispatchMessage(Handler.java:99) 
            at android.os.Looper.loop(Looper.java:193) 
            at android.app.ActivityThread.main(ActivityThread.java:6669) 
            at java.lang.reflect.Method.invoke(Native Method) 
            at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

Answer 1

您应该将 import android.preference.DialogPreference 更改为 import android.support.v7.preference.DialogPreference。

那是因为看起来您正在使用支持库，这样做时要小心，因为您总是需要使用以[=12]开头的类 =].

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