I want to tap on an entry on the listview on my Activity_main to view the details on Activity_View.
When I do so my application crashes.
Where is my coding wrong?
Activity_Main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:weightSum="1">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="71dp"
android:layout_weight="0.35">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="1"
android:focusableInTouchMode="true">
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/txtSearch"
android:layout_weight="0.98"
android:hint="Search..." />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Search"
android:id="@+id/btnSearch" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="1">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Sort By Date"
android:id="@+id/btnSortDate"
android:layout_gravity="left"
android:layout_weight="0.90" />
<Button
android:layout_width="174dp"
android:layout_height="wrap_content"
android:text="Sorty By Title"
android:id="@+id/btnSortTitle"
android:layout_gravity="right" />
</LinearLayout>
</LinearLayout>
<ListView
android:layout_width="wrap_content"
android:layout_height="252dp"
android:id="@+id/listView"
android:layout_weight="0.56" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Create Entry"
android:id="@+id/btnNewEntry"
android:layout_gravity="center_horizontal"
android:layout_marginTop="10dp" />
</LinearLayout>
</RelativeLayout>
MainActivity.Java
public class MainActivity extends AppCompatActivity {
private static final int REQUEST_CODE = 100;
private static List<Entry> entryList;
private ListView lvEntries;
private EntryListAdaptor EntryListadapter;
DatabaseHandler dbHandler;
Uri imageUri = Uri.parse("android.resource://unipersonalinc.mypersonalediary/drawable/download.jpg");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button newBtn = (Button) findViewById(R.id.btnNewEntry);
lvEntries = (ListView) findViewById(R.id.listView);
dbHandler = new DatabaseHandler(getApplicationContext());
entryList = new ArrayList<>();
EntryListadapter = new EntryListAdaptor();
lvEntries.setAdapter(EntryListadapter);
newBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivityForResult(new Intent(MainActivity.this, Activity_Write.class), REQUEST_CODE);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
switch (requestCode) {
case REQUEST_CODE:
if (data != null) {
int id = dbHandler.getEntriesCount();
long time = System.currentTimeMillis();
SimpleDateFormat dayTime = new SimpleDateFormat("dd-MM-yyyy mm:ss");
String date = dayTime.format(new Date(time));
String title = data.getStringExtra("Title");
String passage = data.getStringExtra("Passage");
Entry newEntry = new Entry(id, title, passage, imageUri, date);
entryList.add(newEntry);
dbHandler.createEntry(newEntry);
EntryListadapter.notifyDataSetChanged();
}
break;
}
}
lvEntries.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
int searchId = position - 1;
Cursor cursor = dbHandler.getData(searchId);
String entryTitle = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_TITLE));
String entryPassage = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_PASSAGE));
String entryDate = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_DATE));
Bundle dataBundle = new Bundle();
dataBundle.putString("title", entryTitle);
dataBundle.putString("passage", entryPassage);
dataBundle.putString("date", entryDate);
Intent intent = new Intent(getApplicationContext(), Activity_View.class);
intent.putExtras(dataBundle);
startActivity(intent);
}
});
}
private class EntryListAdaptor extends ArrayAdapter<Entry> {
private TextView tvTitle, tvDate;
public EntryListAdaptor() {
super(MainActivity.this, R.layout.listview_item, entryList);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null)
convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.listview_item, null);
tvTitle = (TextView) convertView.findViewById(R.id.entryTitle);
tvDate = (TextView) convertView.findViewById(R.id.entryDate);
tvTitle.setText(entryList.get(position).getTitle());
tvDate.setText(entryList.get(position).getDate());
return convertView;
}
}
}
activity_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="1">
<ImageView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/ivImage"
android:layout_gravity="center"
android:src="@drawable/download" />
<TextView
android:layout_width="367dp"
android:layout_height="wrap_content"
android:text="Testing"
android:id="@+id/lblTitle"
android:layout_marginTop="10dp"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />
<TextView
android:layout_width="fill_parent"
android:layout_height="222dp"
android:text="this is solely for the storyboard and may not be the final interface of the application"
android:id="@+id/lblPassage"
android:layout_marginTop="10dp"
android:layout_weight="0.82" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1/1/15"
android:id="@+id/lblDate2"
android:layout_gravity="right" />
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:layout_width="100dp"
android:layout_height="wrap_content"
android:text="Edit"
android:id="@+id/btnEdit"
android:layout_marginTop="10dp"
android:layout_gravity="left" />
<Button
android:layout_width="100dp"
android:layout_height="wrap_content"
android:text="Back"
android:id="@+id/btnBack"
android:layout_gravity="right"
android:layout_marginTop="10dp" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
Activity_View.Java
public class Activity_View extends AppCompatActivity {
Button BackBtn = (Button) findViewById(R.id.btnBack);
Button EditBtn = (Button) findViewById(R.id.btnEdit);
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.activity_view);
Bundle extras = getIntent().getExtras();
String entryTitle = extras.getString("title");
TextView title = (TextView) findViewById(R.id.lblTitle);
title.setText(entryTitle);
String entryPassage = extras.getString("passage");
TextView passage = (TextView) findViewById(R.id.lblPassage);
passage.setText(entryPassage);
String entryDate = extras.getString("date");
TextView date = (TextView) findViewById(R.id.lblDate2);
date.setText(entryDate);
BackBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});
}
}
Entry.Java
public class Entry {
public String _title, _passage;
public Uri _imageUri;
public String _date;
public int _id;
public Entry (int id, String title, String passage, Uri imageUri, String date) {
_id = id;
_title = title;
_passage = passage;
_imageUri = imageUri;
_date = date;
}
public int getId() { return _id; }
public String getTitle() {
return _title;
}
public String getPassage() { return _passage; }
public Uri getImageUri() { return _imageUri; }
public String getDate() { return _date; }
}
DatabaseHandler.Java
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
public static final String DATABASE_NAME = "entriesManager",
TABLE_ENTRIES = "entries",
KEY_ID = "id",
KEY_TITLE = "title",
KEY_PASSAGE = "passage",
KEY_IMAGEURI = "imageUri",
KEY_DATE="date";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_ENTRIES + "(" + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_TITLE + " TEXT," + KEY_PASSAGE + " TEXT," + KEY_IMAGEURI + " TEXT" + KEY_DATE + "TEXT)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_ENTRIES);
onCreate(db);
}
public void createEntry(Entry entry) {
SQLiteDatabase db = getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ID,entry.getId());
values.put(KEY_TITLE, entry.getTitle());
values.put(KEY_PASSAGE, entry.getPassage());
values.put(KEY_IMAGEURI, entry.getImageUri().toString());
db.insert(TABLE_ENTRIES, null, values);
db.close();
}
public Entry getEntry(int id) {
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.query(TABLE_ENTRIES, new String[] {KEY_ID, KEY_TITLE, KEY_PASSAGE, KEY_IMAGEURI}, KEY_ID + "=?", new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Entry entry = new Entry(Integer.parseInt(cursor.getString(0)), cursor.getString(1), cursor.getString(2), Uri.parse(cursor.getString(3)), cursor.getString(4));
db.close();
cursor.close();
return entry;
}
public void deleteEntry(Entry entry) {
SQLiteDatabase db = getWritableDatabase();
db.delete(TABLE_ENTRIES, KEY_ID + "=?", new String[]{String.valueOf(entry.getId())});
db.close();
}
public int getEntriesCount() {
SQLiteDatabase db;
db = getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_ENTRIES, null);
int count = cursor.getCount();
db.close();
cursor.close();
return count;
}
public int updataEntry(Entry entry) {
SQLiteDatabase db = getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_TITLE, entry.getTitle());
values.put(KEY_PASSAGE, entry.getPassage());
values.put(KEY_IMAGEURI, entry.getImageUri().toString());
return db.update(TABLE_ENTRIES, values, KEY_ID + "=?", new String[]{String.valueOf(entry.getId())});
}
public List<Entry> getAllEntries() {
List<Entry> entries = new ArrayList<Entry>();
SQLiteDatabase db = getWritableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_ENTRIES, null);
if (cursor.moveToFirst()) {
do {
Entry entry = new Entry(Integer.parseInt(cursor.getString(0)), cursor.getString(1), cursor.getString(2), Uri.parse(cursor.getString(3)), cursor.getString(4));
entries.add(entry);
}
while (cursor.moveToNext());
}
return entries;
}
public Cursor getData(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor res = db.rawQuery("select * from Entries where KEY_ID = " + id, null);
res.moveToFirst();
return res;
}
}
LogCat
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: Process: unipersonalinc.mypersonalediary, PID: 5811 12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{unipersonalinc.mypersonalediary/unipersonalinc.mypersonalediary.Activity_View}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.Window.findViewById(int)' on a null object reference
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2327)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.-wrap11(ActivityThread.java)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.os.Looper.loop(Looper.java:148)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5417)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.Window.findViewById(int)' on a null object reference
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.Activity.findViewById(Activity.java:2090)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at unipersonalinc.mypersonalediary.Activity_View.(Activity_View.java:17)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at java.lang.Class.newInstance(Native Method)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.Instrumentation.newActivity(Instrumentation.java:1067)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2317)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.-wrap11(ActivityThread.java)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.os.Looper.loop(Looper.java:148)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5417) 12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
12-09 06:16:55.140 5811-5811/unipersonalinc.mypersonalediary E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
The error is in your getData() method. Replace
Cursor res = db.rawQuery("select * from Entries where KEY_ID = " + id, null);
with
Cursor res = db.rawQuery("select * from Entries where " + KEY_ID + " = " + id, null);
In your original method you where trying to lookup a Column named KEY_ID, which doesn't exist because KEY_ID is a constant naming your ID column. So you have to insert the value of KEY_ID in the SELECTstatement.
For your new problem, when you get a Cursor you must iterate through its result to get the corresponding data, otherwise you'll get an Exception. For your code, try replacing
Cursor cursor = dbHandler.getData(searchId);
String entryTitle = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_TITLE));
String entryPassage = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_PASSAGE));
String entryDate = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_DATE));
with
Cursor cursor = dbHandler.getData(searchId);
if(cursor.moveToFirst()){
String entryTitle = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_TITLE));
String entryPassage = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_PASSAGE));
String entryDate = cursor.getString(cursor.getColumnIndex(dbHandler.KEY_DATE));
}
Also Check for position and searchId in onItemClick callback
int searchId = position - 1;
Cursor cursor = dbHandler.getData(searchId);
this value should be >=0 ;
For your next problem, change this
public class Activity_View extends AppCompatActivity {
Button BackBtn = (Button) findViewById(R.id.btnBack);
Button EditBtn = (Button) findViewById(R.id.btnEdit);
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.activity_view);
...
to this:
public class Activity_View extends AppCompatActivity {
Button backBtn;
Button editBtn;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.activity_view);
backBtn = (Button) findViewById(R.id.btnBack);
editBtn = (Button) findViewById(R.id.btnEdit);
...