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我想爲我的android應用程序創建一個數據庫。我在我的項目中編寫了一個數據庫的代碼;每當我運行它時都會在模擬器上顯示「強制關閉」。我嘗試過不同的方式，但沒有任何作用。我哪裏做錯了？eclipse中的android sdk的內容提供者
// EventContentProvider.java
package com.event.test;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
public class EventContentProvider extends ContentProvider {
private static final String DATABASE_NAME = "event.db";
private static final UriMatcher sUriMatcher;
private static final int EVENTS = 1;
private static final int EVENT_ID = 2;
private static class DatabaseHelper extends SQLiteOpenHelper {
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE event1 (_ID INTEGER PRIMARY KEY, first_name TEXT, last_name TEXT);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
private DatabaseHelper mOpenHelper;
@Override
public boolean onCreate() {
mOpenHelper = new DatabaseHelper(getContext());
return true;
}
@Override
public int delete(Uri uri, String where, String[] whereArgs) {
SQLiteDatabase db = null;
int count = 0;
try {
db = mOpenHelper.getWritableDatabase();
switch(sUriMatcher.match(uri)){
case EVENTS:
count = db.delete(Event.EVENT_TABLE_NAME, where, whereArgs);
break;
default:
throw new IllegalArgumentException("No content matched");
}
getContext().getContentResolver().notifyChange(uri, null);
} catch(Exception e) {
} finally {
if(db != null)
db.close();
}
return count;
}
@Override
public String getType(Uri uri) {
switch(sUriMatcher.match(uri)){
case EVENTS:
return Event.CONTENT_TYPE;
default:
throw new IllegalArgumentException("No content matched");
}
}
@Override
public Uri insert(Uri uri, ContentValues initialValues) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
ContentValues values;
if (initialValues != null) {
values = new ContentValues(initialValues);
} else {
values = new ContentValues();
}
long rowId = -1;
Uri contentUri = null;
switch(sUriMatcher.match(uri)){
case EVENTS:
rowId = db.insertOrThrow(Event.EVENT_TABLE_NAME, Event._ID, values);
contentUri = ContentUris.withAppendedId(Event.CONTENT_URI, rowId);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
db.close();
if(rowId > 0){
return contentUri;
}
return null;
}
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
long rowId = -1;
try {
switch (sUriMatcher.match(uri)) {
case EVENTS:
rowId = db.update(Event.EVENT_TABLE_NAME, values, selection,
selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
rowId = db.update(Event.EVENT_TABLE_NAME, values, selection,
selectionArgs);
} catch (Exception e) {
} finally {
if(db != null)
db.close();
}
return (int) rowId;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
switch(sUriMatcher.match(uri)){
case EVENTS:
qb.setTables(Event.EVENT_TABLE_NAME);
qb.setProjectionMap(Event.sEventProjectionMap);
break;
default:
throw new IllegalArgumentException("No content matched in query ");
}
SQLiteDatabase db = null;
Cursor c = null;
try {
db = mOpenHelper.getReadableDatabase();
c = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder);
c.setNotificationUri(getContext().getContentResolver(), uri);
} catch (Exception e) {
}
return c;
}
static {
sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
sUriMatcher.addURI(Event.AUTHORITY, "events", EVENTS);
sUriMatcher.addURI(Event.AUTHORITY, "events/#", EVENT_ID);
}
}
//Event.java
package com.event.test;
import java.util.HashMap;
import android.net.Uri;
import android.provider.BaseColumns;
public class Event implements BaseColumns{
public static final String AUTHORITY = "com.event.data.contentprovider";
public static final Uri CONTENT_URI = Uri.parse("content://com.event.data.contentprovider/events");
public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.event.event";
public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.event/vnd.event.event";
public static final String EVENT_TABLE_NAME = "event1";
public static final String FIRSTNAME = "first_name";
public static final String LASTNAME = "last_name";
public static String _ID;
public static HashMap<String,String> sEventProjectionMap;
static {
Event.sEventProjectionMap = new HashMap<String,String>();
Event.sEventProjectionMap.put(Event._ID, Event._ID);
Event.sEventProjectionMap.put(Event.FIRSTNAME, Event.FIRSTNAME);
Event.sEventProjectionMap.put(Event.LASTNAME, Event.LASTNAME);
}
}
//manifestfile.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.event.test"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="10" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".EventManagementActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<provider android:name="com.event.test.EventContentProvider"
android:authorities="com.event.data.contentprovider" />
</application>
</manifest>
//EventManagementActivity.java
package com.event.test;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class EventManagementActivity extends Activity implements OnClickListener{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btn = (Button) findViewById(R.id.btn01);
btn.setText("Press Me");
btn.setOnClickListener(this);
}
@Override
public void onClick(View arg0)
{
switch(arg0.getId()){
case R.id.btn01:
ContentValues cv = new ContentValues();
cv.put(Event.FIRSTNAME, "DATTA");
cv.put(Event.LASTNAME, "Prabhu");
getContentResolver().insert(Event.CONTENT_URI, cv);
String[] str = {Event.FIRSTNAME, Event.LASTNAME};
String where = Event.FIRSTNAME + " = ? AND " +
Event.LASTNAME + " = ?";
String [] whereArgs = {"Datta", "Prabhu"};
Cursor c = getContentResolver().query(Event.CONTENT_URI,
str,
where,
whereArgs,
null);
if (c.moveToFirst()) {
int id = c.getInt(0);
String firstName = c.getString(0);
String lastName = c.getString(1);
EditText edit = (EditText) findViewById(R.id.edit01);
edit.setText(id + firstName + " " + lastName);
TextView tv = (TextView) findViewById(R.id.text01);
tv.setText(id + firstName + " " + lastName);
}
c.close();
break;
}
}
}
//main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=""
android:id="@+id/text01"
/>
<EditText
android:id="@+id/edit01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/btn01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
//R.java
package com.event.test;
public final class R {
public static final class attr {
}
public static final class drawable {
public static final int icon=0x7f020000;
}
public static final class id {
public static final int btn01=0x7f050002;
public static final int edit01=0x7f050001;
public static final int text01=0x7f050000;
}
public static final class layout {
public static final int main=0x7f030000;
}
public static final class string {
public static final int app_name=0x7f040001;
public static final int hello=0x7f040000;
}
}
//logcat
10-04 01:12:06.904: DEBUG/MediaScanner(285): total time: 981ms
10-04 01:12:06.984: DEBUG/MediaScannerService(285): done scanning volume internal
10-04 01:12:07.344: DEBUG/dalvikvm(216): GC_CONCURRENT freed 243K, 51% free 2798K/5703K, external 410K/517K, paused 4ms+3ms
10-04 01:12:07.854: DEBUG/dalvikvm(178): GC_EXPLICIT freed 331K, 50% free 2952K/5895K, external 1313K/1400K, paused 64ms
10-04 01:12:12.318: WARN/ActivityManager(73): Activity destroy timeout for HistoryRecord{4072bb18 com.event.test/.EventManagementActivity}
10-04 01:12:15.079: INFO/InputReader(73): Device reconfigured: id=0x0, name=qwerty2, display size is now 240x432
10-04 01:12:15.079: INFO/InputManager-Callbacks(73): No virtual keys found for device qwerty2.
10-04 01:12:15.653: INFO/ARMAssembler(73): generated scanline__00000177:03515104_00001001_00000000 [ 91 ipp] (114 ins) at [0x44325520:0x443256e8] in 1138243 ns
10-04 01:12:16.543: INFO/dalvikvm(73): Jit: resizing JitTable from 512 to 1024
10-04 01:12:18.393: INFO/Process(239): Sending signal. PID: 239 SIG: 9
10-04 01:12:18.403: INFO/ActivityManager(73): Process com.event.test (pid 239) has died.
10-04 01:12:21.153: DEBUG/dalvikvm(178): GC_EXTERNAL_ALLOC freed 61K, 51% free 2947K/5895K, external 1202K/1400K, paused 48ms
10-04 01:12:24.723: INFO/ActivityManager(73): Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.event.test/.EventManagementActivity } from pid 178
10-04 01:12:24.773: INFO/ActivityManager(73): Start proc com.event.test for activity com.event.test/.EventManagementActivity: pid=335 uid=10034 gids={}
10-04 01:12:25.253: INFO/ARMAssembler(73): generated scanline__00000177:03515104_00001002_00000000 [ 87 ipp] (110 ins) at [0x443256f0:0x443258a8] in 551089 ns
10-04 01:12:25.303: INFO/ActivityThread(335): Pub com.event.data.contentprovider: com.event.test.EventContentProvider
10-04 01:12:25.583: DEBUG/AndroidRuntime(335): Shutting down VM
10-04 01:12:25.583: WARN/dalvikvm(335): threadid=1: thread exiting with uncaught exception (group=0x40015560)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): FATAL EXCEPTION: main
10-04 01:12:25.594: ERROR/AndroidRuntime(335): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.event.test/com.event.test.EventManagementActivity}: java.lang.NullPointerException
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.os.Handler.dispatchMessage(Handler.java:99)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.os.Looper.loop(Looper.java:123)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.app.ActivityThread.main(ActivityThread.java:3683)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at java.lang.reflect.Method.invokeNative(Native Method)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at java.lang.reflect.Method.invoke(Method.java:507)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at dalvik.system.NativeStart.main(Native Method)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): Caused by: java.lang.NullPointerException
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at com.event.test.EventManagementActivity.onCreate(EventManagementActivity.java:21)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
10-04 01:12:25.594: ERROR/AndroidRuntime(335): ... 11 more
10-04 01:12:25.603: WARN/ActivityManager(73): Force finishing activity com.event.test/.EventManagementActivity
10-04 01:12:26.123: WARN/ActivityManager(73): Activity pause timeout for HistoryRecord{4070aaa0 com.event.test/.EventManagementActivity}
10-04 01:12:27.503: INFO/Process(335): Sending signal. PID: 335 SIG: 9
10-04 01:12:27.543: WARN/InputManagerService(73): Window already focused, ignoring focus gain of: [email protected]
10-04 01:12:27.874: INFO/ActivityManager(73): Process com.event.test (pid 335) has died.
10-04 01:12:36.575: WARN/ActivityManager(73): Activity destroy timeout for HistoryRecord{4070aaa0 com.event.test/.EventManagementActivity}
logcat中是否有任何錯誤消息？ – spatulamania
傢伙請幫忙！我粘貼了上面不同文件的代碼。如果你無法理解，請通知 – sameerismyname
如果你收到一個錯誤，你必須發佈它，否則我們不知道錯誤是什麼。 logcat中的堆棧跟蹤通常指向導致錯誤的確切代碼行。 //www.winksaville.com/blog/programming/debug-logging-in-android/ – Jack