使用内容提供者获取日历实例

Question

我正在尝试实现日历实例查询https://developer.android.com/guide/topics/providers/calendar-provider#query-instances，但是当我运行代码时，我的光标返回null。我删除了选择args，以便它应返回查询范围内的所有实例，但仍然没有运气。我什至将范围设置为回溯2年（其中日历中有很多事件），但它仍然返回null。执行以下代码时，有人会遇到相同的问题吗？

package com.strath.keepfitct.utils;

import android.Manifest;
import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.net.Uri;
import android.provider.CalendarContract;
import android.util.Log;

import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;
import java.util.TimeZone;

public class CalendarManager
{
    private static final int PERMISSION_REQUEST_CODE = 1;
    private static final String DEBUG_TAG = "CalendarManager";

    private static final String[] INSTANCE_PROJECTION = new String[]
            {
            CalendarContract.Instances.EVENT_ID,      // 0
            CalendarContract.Instances.BEGIN,         // 1
            CalendarContract.Instances.TITLE,          // 2
            CalendarContract.Instances.END,         // 3
    };

    private static final int PROJECTION_ID_INDEX = 0;
    private static final int PROJECTION_BEGIN_INDEX = 1;
    private static final int PROJECTION_TITLE_INDEX = 2;
    private static final int PROJECTION_END_INDEX = 3;


    public static void getEvents(Context context)
    {
        Cursor cursor = null;
        ContentResolver contentResolver = context.getContentResolver();

        long startTime = LocalDateTime.now().minusMonths(24).toEpochSecond(OffsetDateTime.now().getOffset());
        long endTime = LocalDateTime.now().plusHours(24).toEpochSecond(OffsetDateTime.now().getOffset());

        Uri.Builder builder = CalendarContract.Instances.CONTENT_URI.buildUpon();
        ContentUris.appendId(builder, startTime);
        ContentUris.appendId(builder, endTime);

//        String selection = CalendarContract.Instances.EVENT_ID + " = ?";
//        String[] selectionArgs = new String[] {"207"};

        if (ContextCompat.checkSelfPermission(context, Manifest.permission.READ_CALENDAR)
                != PackageManager.PERMISSION_GRANTED)
        {
            Log.d("permission", "permission denied to READ_CALENDAR - requesting it");

            ActivityCompat.requestPermissions((Activity) context, new String[] {Manifest.permission.READ_CALENDAR}, PERMISSION_REQUEST_CODE);
        }
        else
        {
            Log.d("Content URI", builder.build().toString());
            cursor =  contentResolver.query(builder.build(),
                    INSTANCE_PROJECTION,
                    null,
                    null,
                    null);

            while (cursor.moveToNext())
            {
                String title = null;
                long eventID = 0;
                long beginVal = 0;

                // Get the field values
                eventID = cursor.getLong(PROJECTION_ID_INDEX);
                beginVal = cursor.getLong(PROJECTION_BEGIN_INDEX);
                title = cursor.getString(PROJECTION_TITLE_INDEX);

                // Do something with the values.
                Log.i(DEBUG_TAG, "Event:  " + title);
                LocalDateTime date = LocalDateTime.ofInstant(Instant.ofEpochSecond(beginVal), TimeZone.getDefault().toZoneId());
                Log.i(DEBUG_TAG, "Date: " + date.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME));
            }
        }
    }
}

Answer 1

我的问题是，在将LocalDateTime参数转换为很长的时间后，我没有像预期的那样将它们转换为毫秒！快速乘以1000可解决此问题。

long startTime = LocalDateTime.now().minusMonths(24).toEpochSecond(OffsetDateTime.now().getOffset()) * 1000;