我是Android应用程序开发的新手，我正在尝试开发一个应用程序，它将在我的Android手机中添加一个事件。这是我试过的代码：
问题：我的应用程序崩溃了。
AddCalendarEventTestAction.java
package com.app.mytestapp;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.provider.CalendarContract;
import android.util.Log;
import java.util.Calendar;
import java.util.HashMap;
import java.util.TimeZone;
public class AddCalendarEventTestAction {
String[] CALENDAR_QUERY_COLUMNS = { "_id", "name", "visible", "ownerAccount" };
CalendarContract contract;
String eventStartTitle = "POST Test";
int eventStartYear;
Context contx;
public AddCalendarEventTestAction()
{
}
private void addEvent()
{
Calendar localCalendar1 = Calendar.getInstance();
localCalendar1.set(2015, 3, 4, 1, 40);
// localCalendar1.set(this.eventStartYear, this.eventStartMonth, this.eventStartDate, this.eventStartHour, this.eventStartMinute);
Calendar localCalendar2 = Calendar.getInstance();
localCalendar2.set(2015, 3, 4, 3, 45);
ContentResolver localContentResolver = contx.getContentResolver();
Log.d("Test",CalendarContract.Calendars.CONTENT_URI.toString());
Cursor localCursor = localContentResolver.query(CalendarContract.Calendars.CONTENT_URI, CALENDAR_QUERY_COLUMNS, null, null, null);
Log.d("Test","Calendar cursor = " + localCursor);
if (localCursor.moveToNext())
{
localCursor.getString(0);
localCursor.getString(1);
if (!localCursor.getString(2).equals("0"));
for (boolean bool = true; ; bool = false)
{
Boolean.valueOf(bool);
String str = localCursor.getString(3);
Log.d("Test","Found calendar " + str);
break;
}
}
TimeZone timeZone = TimeZone.getDefault();
ContentValues localContentValues = new ContentValues();
localContentValues.put(CalendarContract.Events.CALENDAR_ID, Integer.valueOf(1));
localContentValues.put(CalendarContract.Events.TITLE, this.eventStartTitle);
localContentValues.put(CalendarContract.Events.DTSTART, localCalendar1.getTimeInMillis());
localContentValues.put(CalendarContract.Events.EXDATE, localCalendar2.getTimeInMillis());
localContentValues.put(CalendarContract.Events.EVENT_TIMEZONE, timeZone.getID());
Integer.parseInt(localContentResolver.insert(CalendarContract.Events.CONTENT_URI, localContentValues).getLastPathSegment());
}
public void start()
{
addEvent();
}
}
MainActivity.java
package com.app.mytestapp;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.telephony.SmsManager;
import android.view.View;
import java.util.ArrayList;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void performAction(View view)
{
AddCalendarEventTestAction calobj = new AddCalendarEventTestAction();
calobj.start();
}
}
Menifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.app.mytestapp" >
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.SEND_SMS">
</uses-permission>
<uses-permission android:name="android.permission.RECEIVE_SMS">
</uses-permission>
<uses-permission android:name="android.permission.READ_CALENDAR" />
<uses-permission android:name="android.permission.WRITE_CALENDAR" />
</manifest>
Logcat：
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:3823)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18439)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5034)
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:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.view.View$1.onClick(View.java:3818)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18439)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5034)
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:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.app.mytestapp.AddCalendarEventTestAction.addEvent(AddCalendarEventTestAction.java:38)
at com.app.mytestapp.AddCalendarEventTestAction.start(AddCalendarEventTestAction.java:68)
at com.app.mytestapp.MainActivity.performAction(MainActivity.java:48)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.view.View$1.onClick(View.java:3818)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18439)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5034)
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:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method
答案 0 :(得分：0)
找到解决方案：我没有初始化上下文，这就是我的应用程序崩溃的原因。刚刚添加下面的代码
Context mycontx;
public AddCalendarEventTestAction(Context contx)
{
mycontx =contx;
}