java.lang.RuntimeException的:无法启动的活动ComponentInfo {...}:显示java.lang.NullPointerException [英] java.lang.RuntimeException: Unable to start activity ComponentInfo {...}: java.lang.NullPointerException
问题描述
当您单击从一个活动到另一个去,我有一个错误:
了java.lang.RuntimeException:无法启动活动ComponentInfo {...}:显示java.lang.NullPointerException
我缺少一些方法?请帮我明白我做错了什么,这就是为什么你看到这个错误?
我的活动:Zaselenie.java
进口的java.util.ArrayList;
进口android.app.Activity;
进口android.database.Cursor;
进口android.database.sqlite.SQLiteDatabase;
进口android.os.Bundle;
进口android.util.Log;
进口android.widget.ArrayAdapter;
进口android.widget.Spinner;
公共类Zaselenie延伸活动{
ContactDBmoy CQH;
KvartDB KDB;
SQLiteDatabase深发展;
私人龙ROWID;
微调spZaselenie;
@覆盖
保护无效的onCreate(包savedInstanceState){
super.onCreate(savedInstanceState);
的setContentView(R.layout.zaselenie);
spZaselenie =(微调)findViewById(R.id.spZaselenie);
//Инициализируемнашкласс,обёртку
CQH =新ContactDBmoy(Zaselenie.this);
KDB =新KvartDB(Zaselenie.this);
//Базанамнужнадлязаписиичтения
SDB = cqh.getWritableDatabase();
SDB = kdb.getWritableDatabase();
捆绑额外= getIntent()getExtras()。
ROWID = extras.getLong(ContactMain.rowId);
光标cursorKvart = sdb.query(KvartDB.TABLE_NAME,新的String [] {
KvartDB._ID,KvartDB.NAME_COLUMN},空,//将
//列
// 为了
// 哪里
// 条款
空,//值的WHERE子句
NULL,//不群的行
空,//不要被行组筛选
空//排序顺序
);
ArrayList的<字符串>标签=新的ArrayList<字符串>();
而(cursorKvart.moveToNext()){
//获取这些列列索引+ VALUES
INT idKvart = cursorKvart.getInt(cursorKvart.getColumnIndex(KvartDB._ID));
串nameKvart = cursorKvart.getString(cursorKvart.getColumnIndex(KvartDB.NAME_COLUMN));
Log.i(LOG_TAG,行+ idKvart +也名+ nameKvart);
labels.add(nameKvart);
//创建适配器微调
ArrayAdapter<字符串> DataAdapter的=新的ArrayAdapter<字符串>(这一点,
android.R.layout.simple_spinner_item,标签);
//下拉布局样式 - 列表视图单选按钮
DataAdapter的
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dataAdapter.notifyDataSetChanged();
//连接数据适配器微调器
spZaselenie.setAdapter(DataAdapter的);
}
cursorKvart.close();
}
公共Zaselenie(){
// TODO自动生成构造函数存根
}
@覆盖
保护无效onResume(){
super.onResume();
}
@覆盖
保护无效的onStop(){
super.onStop();
//закрываемсоединениясбазойданных
sdb.close();
kdb.close();
}
}
logcat的错误:
12月3号至6日:04:43.802:E / AndroidRuntime(20861):致命异常:主要
12月3号至六日:04:43.802:E / AndroidRuntime(20861):java.lang.RuntimeException的:无法启动的活动ComponentInfo {ru.zloyel.manager_sutochnoy_arendy_1 / ru.zloyel.manager_sutochnoy_arendy_1.Zaselenie}:显示java.lang.NullPointerException
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.ActivityThread.access $ 600(ActivityThread.java:130)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1195)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.os.Handler.dispatchMessage(Handler.java:99)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.os.Looper.loop(Looper.java:137)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.ActivityThread.main(ActivityThread.java:4745)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在java.lang.reflect.Method.invokeNative(本机方法)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在java.lang.reflect.Method.invoke(Method.java:511)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:786)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在dalvik.system.NativeStart.main(本机方法)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):由:显示java.lang.NullPointerException
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在ru.zloyel.manager_sutochnoy_arendy_1.Zaselenie.onCreate(Zaselenie.java:39)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.Activity.performCreate(Activity.java:5008)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
12月3号至六日:04:43.802:E / AndroidRuntime(20861):11 ...更多
检查演员
不是空
如下...
如果(临时演员!= NULL){
ROWID = extras.getLong(ContactMain.rowId);
}
另外,请检查你的光标
对象不为空,如下...
如果(cursorKvart = NULL和放大器;!&安培; cursorKvart.getCount()0){
而(cursorKvart.moveToNext()){
......
}
}
when you click to go from one activity to another, I have an error:
java.lang.RuntimeException: Unable to start activity ComponentInfo {...}: java.lang.NullPointerException
I am missing some method? Please help me to understand what I did wrong, which is why you see this error?
My activity: Zaselenie.java
import java.util.ArrayList;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
public class Zaselenie extends Activity {
ContactDBmoy cqh;
KvartDB kdb;
SQLiteDatabase sdb;
private Long rowId;
Spinner spZaselenie;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.zaselenie);
spZaselenie = (Spinner)findViewById(R.id.spZaselenie);
// Инициализируем наш класс-обёртку
cqh = new ContactDBmoy(Zaselenie.this);
kdb = new KvartDB(Zaselenie.this);
// База нам нужна для записи и чтения
sdb = cqh.getWritableDatabase();
sdb = kdb.getWritableDatabase();
Bundle extras = getIntent().getExtras();
rowId = extras.getLong(ContactMain.rowId);
Cursor cursorKvart = sdb.query(KvartDB.TABLE_NAME, new String[] {
KvartDB._ID, KvartDB.NAME_COLUMN }, null, // The
// columns
// for the
// WHERE
// clause
null, // The values for the WHERE clause
null, // don't group the rows
null, // don't filter by row groups
null // The sort order
);
ArrayList<String> labels = new ArrayList<String>();
while (cursorKvart.moveToNext()) {
// GET COLUMN INDICES + VALUES OF THOSE COLUMNS
int idKvart = cursorKvart.getInt(cursorKvart.getColumnIndex(KvartDB._ID));
String nameKvart = cursorKvart.getString(cursorKvart.getColumnIndex(KvartDB.NAME_COLUMN));
Log.i("LOG_TAG", "ROW " + idKvart + " HAS NAME " + nameKvart);
labels.add(nameKvart);
// Creating adapter for spinner
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, labels);
// Drop down layout style - list view with radio button
dataAdapter
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dataAdapter.notifyDataSetChanged();
// attaching data adapter to spinner
spZaselenie.setAdapter(dataAdapter);
}
cursorKvart.close();
}
public Zaselenie() {
// TODO Auto-generated constructor stub
}
@Override
protected void onResume() {
super.onResume();
}
@Override
protected void onStop() {
super.onStop();
// закрываем соединения с базой данных
sdb.close();
kdb.close();
}
}
Logcat error:
03-06 12:04:43.802: E/AndroidRuntime(20861): FATAL EXCEPTION: main
03-06 12:04:43.802: E/AndroidRuntime(20861): java.lang.RuntimeException: Unable to start activity ComponentInfo{ru.zloyel.manager_sutochnoy_arendy_1/ru.zloyel.manager_sutochnoy_arendy_1.Zaselenie}: java.lang.NullPointerException
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.ActivityThread.access$600(ActivityThread.java:130)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.os.Handler.dispatchMessage(Handler.java:99)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.os.Looper.loop(Looper.java:137)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.ActivityThread.main(ActivityThread.java:4745)
03-06 12:04:43.802: E/AndroidRuntime(20861): at java.lang.reflect.Method.invokeNative(Native Method)
03-06 12:04:43.802: E/AndroidRuntime(20861): at java.lang.reflect.Method.invoke(Method.java:511)
03-06 12:04:43.802: E/AndroidRuntime(20861): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
03-06 12:04:43.802: E/AndroidRuntime(20861): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-06 12:04:43.802: E/AndroidRuntime(20861): at dalvik.system.NativeStart.main(Native Method)
03-06 12:04:43.802: E/AndroidRuntime(20861): Caused by: java.lang.NullPointerException
03-06 12:04:43.802: E/AndroidRuntime(20861): at ru.zloyel.manager_sutochnoy_arendy_1.Zaselenie.onCreate(Zaselenie.java:39)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.Activity.performCreate(Activity.java:5008)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
03-06 12:04:43.802: E/AndroidRuntime(20861): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
03-06 12:04:43.802: E/AndroidRuntime(20861): ... 11 more
Check that extras
isn't null
as below...
if(extras != null) {
rowId = extras.getLong(ContactMain.rowId);
}
Also check that your Cursor
object isn't null as below...
if(cursorKvart != null && cursorKvart.getCount() > 0) {
while (cursorKvart.moveToNext()) {
......
}
}
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