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I don't know why i am still getting "android.os.NetworkOnMainThreadException" error, while using AsyncTask [duplicate]

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NetworkOnMainThreadException [duplicate]
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Closed 4 years ago.
I am new to android programming and i am trying to get my head around the AsyncTask concept so please review this code and tell me why it is crashing and keeps giving the "android.os.NetworkOnMainThreadException" error.
This app just tells the weather according to the given x and y coordinates using a bit web scraping.
Here is my code:
public class MainActivity extends AppCompatActivity {
TextView weatherInfo;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
weatherInfo = (TextView) findViewById(R.id.weather_info);
Weathers runner = new Weathers();
String GetInfo = runner.doInBackground();
weatherInfo.append(GetInfo);
}
}
class Weathers extends AsyncTask<String,String,String>{
#Override
protected String doInBackground(String... strings) {
String x="19.11";
String y="72.88";
String result = null;
try {
Document doc = Jsoup.connect("https://weather.com/en-IN/weather/today/l/"+x+","+y).get();
for (Element row : doc.select("header[class=loc-container]") ){
result=row.text();
}
for (Element row : doc.select("div[class=today_nowcard-section today_nowcard-condition]") ){
result=result+(row.text());
}
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
}
Here is the Android Manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.inferno.sunshine">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<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.INTERNET"/>
</manifest>

Use this
String GetInfo = runner.execute();
Instead of this
String GetInfo = runner.doInBackground();

try this
public class MainActivity extends AppCompatActivity {
TextView weatherInfo;
String GetInfo = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
weatherInfo = (TextView) findViewById(R.id.weather_info);
Weathers runner = new Weathers();
runner.execute();
}
}
class Weathers extends AsyncTask<String,String,String>{
String result = "";
#Override
protected String doInBackground(String... strings) {
String x="19.11";
String y="72.88";
try {
Document doc = Jsoup.connect("https://weather.com/en-IN/weather/today/l/"+x+","+y).get();
for (Element row : doc.select("header[class=loc-container]") ){
result=row.text();
}
for (Element row : doc.select("div[class=today_nowcard-section today_nowcard-condition]") ){
result=result+(row.text());
}
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
#Override
protected void onPostExecute(Void aVoid) {
weatherInfo.append(result);
}
}

Can't get Android ContentProvider to work

I am trying to put together a simple app to help me understand the content provider but I can't get it to work. I want to insert data into a database but I think the problem I have is somewhere with the URI.
** I am trying to follow a similar pattern as shown in the Udacity tutorials
Here is what I have
Android Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.android.simplecontentprovider">
<provider
android:authorities="com.example.android.simplecontentprovider.app"
android:name=".data.MyContentProvider" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
ContentProvider:
public class MyContentProvider extends ContentProvider {
MyDatabaseHelper mOpenHelper;
private static final int NAME = 1;
// Creates a UriMatcher object.
private static final UriMatcher sUriMatcher = buildUriMatcher();
static UriMatcher buildUriMatcher() {
final UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
final String authority = MyDataContract.CONTENT_AUTHORITY; // Value = com.example.android.simplecontentprovider.app
matcher.addURI(authority, MyDataContract.PATH_TABLE, NAME); //PATH_TABLE = tblUserData
//matcher.addURI(authority, MyDataContract.PATH_TABLE + "/*", NAME);
return matcher;
}
#Override
public boolean onCreate() {
mOpenHelper = new MyDatabaseHelper(getContext());
return true;
}
#Override
public Cursor query(Uri uri, String[] strings, String s, String[] strings1, String s1) {
return null;
}
#Override
public String getType(Uri uri) {
int match = sUriMatcher.match(uri);
switch (match){
case NAME:
return MyDataContract.UserDetailsEntry.CONTENT_TYPE;
default:
throw new UnsupportedOperationException("UNKNOWN URI: " + uri);
}
}
#Override
public Uri insert(Uri uri, ContentValues contentValues) {
final SQLiteDatabase db = mOpenHelper.getWritableDatabase();
final int match = sUriMatcher.match(uri);
Uri returnUri;
switch (match) {
case NAME: {
long _id = db.insert(MyDataContract.UserDetailsEntry.TABLE_NAME, null, contentValues);
if ( _id > 0 )
returnUri = MyDataContract.UserDetailsEntry.buildtblUserDetailsUri(_id);
else
throw new android.database.SQLException("Failed to insert row into " + uri);
break;
}
default:
throw new UnsupportedOperationException("Unknown uri: " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return returnUri;
}
#Override
public int delete(Uri uri, String s, String[] strings) {
return 0;
}
#Override
public int update(Uri uri, ContentValues contentValues, String s, String[] strings) {
return 0;
}
}
and finally the MainActivity
ContentResolver resolver = getContentResolver();
Uri uri = MyDataContract.UserDetailsEntry.buildtblUserDetailsAll("MyTestName");
Log.e("RESOLVER URI: ", uri.toString());
ContentValues values = new ContentValues();
values.put(MyDataContract.UserDetailsEntry.COLUMN_NAME, "MyTestName");
try {
resolver.insert(uri, values);
}catch (Exception e){
Log.e("RESOLVER INSERT: ", e.toString());
}
When I run it through the debugger I get this message:
java.lang.IllegalArgumentException: Unknown URL content://com.example.android.simplecontentprovider.app/tblUserData/MyTestName
this is the default value for the insert in the content provider. I am not sure if I am missing the authority part

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.android.simplecontentprovider">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<provider
android:authorities="com.example.android.simplecontentprovider.app"
android:name=".data.MyContentProvider" />
</application>
</manifest>

IllegalArgumentException: Unknown URL content:// CONTENT

IllegalArgumentException: Unknown URL content://
^ Having a nightmare with the above. I've checked my variables and paths but can't see what the issue is? Greatly appreciate any pointers!
Here's my trace.
java.lang.IllegalArgumentException: Unknown URL
content://com.purewowstudio.topmovies.data.FilmProvider/film_data
at android.content.ContentResolver.insert(ContentResolver.java:1203)
at com.purewowstudio.topmovies.data.DatabaseHelper.addFilm(DatabaseHelper.java:52)
at com.purewowstudio.topmovies.fragments.FilmList$getFilms.onPostExecute(FilmList.java:72)
at com.purewowstudio.topmovies.fragments.FilmList$getFilms.onPostExecute(FilmList.java:62)
at android.os.AsyncTask.finish(AsyncTask.java:632)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5262)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:898)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)
Content Provider
public class FilmProvider extends ContentProvider {
public static final String TABLE_NAME = "film_data";
public static final String AUTHORITY = "com.purewowstudio.topmovies.data.FilmProvider";
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/" + TABLE_NAME);
public static final int FILMS = 1;
public static final int FILMS_ID = 2;
public static final UriMatcher sURIMatcher =
new UriMatcher(UriMatcher.NO_MATCH);
static {
sURIMatcher.addURI(AUTHORITY, TABLE_NAME, FILMS);
sURIMatcher.addURI(AUTHORITY, TABLE_NAME + "/#",
FILMS_ID);
}
private DatabaseHelper mDB;
public boolean onCreate() {
mDB = new DatabaseHelper(getContext(), null, null, 1);
return false;
}
#Override
public String getType(Uri uri) {
return null;
}
#Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
queryBuilder.setTables(MovieDataContract.TABLE_NAME);
int uriType = sURIMatcher.match(uri);
switch (uriType) {
case FILMS_ID:
queryBuilder.appendWhere(MovieDataContract.FilmEntry._ID + "="
+ uri.getLastPathSegment());
break;
case FILMS:
break;
default:
throw new IllegalArgumentException("Unknown URI");
}
Cursor cursor = queryBuilder.query(mDB.getReadableDatabase(),
projection, selection, selectionArgs, null, null,
sortOrder);
cursor.setNotificationUri(getContext().getContentResolver(),
uri);
return cursor;
}
#Override
public Uri insert(Uri uri, ContentValues values) {
int uriType = sURIMatcher.match(uri);
SQLiteDatabase sqlDB = mDB.getWritableDatabase();
long id = 0;
switch (uriType) {
case FILMS:
id = sqlDB.insert(MovieDataContract.TABLE_NAME,
null, values);
break;
default:
throw new IllegalArgumentException("Unknown URI: "
+ uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return Uri.parse(MovieDataContract.TABLE_NAME + "/" + id);
}
DatabaseHelper Class
public class DatabaseHelper extends SQLiteOpenHelper {
private ContentResolver myCR;
public DatabaseHelper(Context context, String name,
SQLiteDatabase.CursorFactory factory, int version) {
super(context, MovieDataContract.DATABASE_NAME, factory, MovieDataContract.DATABASE_VERSION);
myCR = context.getContentResolver();
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(MovieDataContract.FilmEntry.SQL_CREATE_TABLE);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL(MovieDataContract.FilmEntry.DELETE_TABLE);
onCreate(db);
}
public void addFilm(Film film){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(MovieDataContract.FilmEntry.COLUMN_FILM_TITLE, film.getTitle());
values.put(MovieDataContract.FilmEntry.COLUMN_FILM_RATING, film.getRating());
values.put(MovieDataContract.FilmEntry.COLUMN_FILM_RUNTIME, film.getRuntime());
values.put(MovieDataContract.FilmEntry.COLUMN_FILM_CRITICS, film.getCritics());
values.put(MovieDataContract.FilmEntry.COLUMN_FILM_AUDIENCE, film.getAudience());
values.put(MovieDataContract.FilmEntry.COLUMN_FILM_SYNOPSIS, film.getSynopsis());
values.put(MovieDataContract.FilmEntry.COLUMN_FILM_PROFILE, film.getProfile());
myCR.insert(FilmProvider.CONTENT_URI, values);
db.insert(MovieDataContract.TABLE_NAME,
null,
values);
db.close();
}
Manifest
<?xml version="1.0" encoding="utf-8"?>
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/TopMoviesTheme" >
<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>
<activity
android:name=".DetailFragment"
android:label="#string/title_activity_detail_fragment"
android:parentActivityName=".MainActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.purewowstudio.topmovies.MainActivity" />
<provider
android:name=".data.filmProvider"
android:authorities="com.purewowstudio.topmovies.data.filmProvider"
android:exported="true">
</provider>
</activity>
</application>
</manifest>

First, move <provider> to be a child of <application>, not <activity>.
Second, change android:exported="true" to android:exported="false", until such time as you secure your ContentProvider. As it stands, once you fix the <provider> element location as noted above, any app can read and write anything in your provider, which is unlikely to be what the user wants.

I have added package name in authorities.that's why I got this issue.I have to add Provider name in authorities.
<provider
android:name="LoginContentProvider"
android:authorities="com.provider.name.team"
android:exported="false" />

android: saving json to sqlite

i'm a new bie in android and java i want to save a table from sql server(external database) to sqlite(internal database).
1. my json is not getting stored and every record is same like this "com.example.db_client.DeptTable#b3e4e9e0" when i opens the db file in sqlite browser. I don't understand what is this.
when i run my app i sometimes get this exception and sometimes i don't.
FATAL EXCEPTION: main
Process: com.example.db_client, PID: 1697
java.lang.IllegalArgumentException: Activity DeptActivity does not have a parent activity name specified. (Did you forget to add the android.support.PARENT_ACTIVITY element in your manifest?)
I really need help please look into my problem. thanks in advance.
code of database helper class
public class SqliteDB {
public static final String KEY_ID = "no";
public static final String KEY_NAME = "name";
private static final String TAG = "DBAdapter";
private static final String DATABASE_NAME = "SQLiteDB";
private static final String TABLE_NAME = "Department";
private static final int DATABASE_VERSION = 2;
private static final String CREATE_TABLE =
"create table departmentList (id INTEGER PRIMARY KEY, name TEXT);";
private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;
public SqliteDB(Context ctx) {
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
try {
db.execSQL(CREATE_TABLE);
} catch (SQLException e) {
e.printStackTrace();
}
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS sample");
onCreate(db);
}
}
//---open SQLite DB---
public SqliteDB open() throws SQLException {
db = DBHelper.getWritableDatabase();
return this;
}
//---close SQLite DB---
public void close() {
DBHelper.close();
}
//---insert data into SQLite DB---
public long insert(String name) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
return db.insert(TABLE_NAME, null, initialValues);
}
//---Delete All Data from table in SQLite DB---
public void deleteAll() {
db.delete(TABLE_NAME, null, null);
}
//---Get All Contacts from table in SQLite DB---
public Cursor getAllData() {
return db.query(TABLE_NAME, new String[] {KEY_NAME},
null, null, null, null, null);
}
}
code of activity class
public class DeptActivity extends Activity{
ArrayAdapter<String> adapter;
ListView listv;
Context context;
ArrayList<String> data;
SqliteDB sqlite;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dept);
sqlite = new SqliteDB(DeptActivity.this);
setupActionBar();
data = new ArrayList<String>();
listv = (ListView) findViewById(R.id.lv_dept);
context = this;
adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, data);
listv.setAdapter(adapter);
Toast.makeText(this,"Loading Please Wait..",Toast.LENGTH_SHORT).show();
new AsyncLoadDeptDetails().execute();
}
public class AsyncLoadDeptDetails extends
AsyncTask<Void, JSONObject, ArrayList<DeptTable>> {
ArrayList<DeptTable> deptTable = null;
#Override
public ArrayList<DeptTable> doInBackground(Void... params) {
// TODO Auto-generated method stub
RestAPI api = new RestAPI();
try {
JSONObject jsonObj = api.GetDepartmentDetails();
JSONParser parser = new JSONParser();
Log.i( "department list", jsonObj.toString());
deptTable = parser.parseDepartment(jsonObj);
sqlite();
} catch (Exception e) {
}
return deptTable;
}
private void sqlite() {
// TODO Auto-generated method stub
sqlite.open();
for(int i=0; i<deptTable.size(); i++) {
sqlite.insert(deptTable.get(i).toString());
}
sqlite.close();
}
#Override
protected void onPostExecute(ArrayList<DeptTable> result) {
// TODO Auto-generated method stub
for (int i = 0; i < result.size(); i++) {
data.add(result.get(i).getNo() + " " + result.get(i).getName());
}
adapter.notifyDataSetChanged();
Toast.makeText(context,"Loading Completed",Toast.LENGTH_SHORT).show();
} }
and the table which i want to save in sqlite db looks like this.
no. name
1 engineering
2 finance
3 commerce
public class DeptTable {
int no;
String name;
public DeptTable(int no, String name) {
super();
this.no = no;
this.name = name;
}
code of deptTable Class
public DeptTable() {
super();
this.no=0;
this.name = null;
}
public int getNo() {
return no;
}
public void setNo(int no) {
this.no = no;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
code of json parser class
public class JSONParser {
public JSONParser()
{
super();
}
public ArrayList<DeptTable> parseDepartment(JSONObject object)
{
ArrayList<DeptTable> arrayList=new ArrayList<DeptTable>();
try {
JSONArray jsonArray=object.getJSONArray("Value");
JSONObject jsonObj=null;
for(int i=0;i<jsonArray.length();i++)
{
jsonObj =jsonArray.getJSONObject(i);
arrayList.add(new DeptTable(jsonObj.getInt("no"), jsonObj.getString("name")));
}
} catch (JSONException e) {
// TODO Auto-generated catch block
Log.d("JSONParser => parseDepartment", e.getMessage());
}
return arrayList;
}
public boolean parseUserAuth(JSONObject object)
{ boolean userAtuh=false;
try {
userAtuh = object.getBoolean("Value");
} catch (JSONException e) {
// TODO Auto-generated catch block
Log.d("JSONParser => parseUserAuth", e.getMessage());
}
return userAtuh; }
code of manifest
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#drawable/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>
<activity
android:name="com.example.db_client.DeptActivity"
android:label="#string/app_name" >
</activity>
</application>
</manifest>
enter code here

If you want to use the toString method the class has to implement the toString method otherwise it will just return the default for object with you find out is not so useful. (This "com.example.db_client.DeptTable#b3e4e9e0"). To implement it just type do like this.
#Override
public String toString() {
//What you want to return here.
}
But I'm guessing you want to add some value to the database so you want to call the getter method of your class like this.
private void sqlite() {
sqlite.open();
for(int i=0; i<deptTable.size(); i++) {
sqlite.insert(deptTable.get(i).getName());
}
sqlite.close();
}
You need to add the android:parentActivityName field to DeptActivity like this.
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#drawable/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>
<activity
android:name="com.example.db_client.DeptActivity"
android:label="#string/app_name"
android:parentActivityName=".MainActivity">
</activity>
</application>
</manifest>

java.lang.InstantiationException: can't instantiate class; no empty constructor

I know this error is pretty common and I also know that I should just add the empty constructor like
public MainActivity(){
super("MainActivity");
but in my case it won't accept a string as an argument, so I don't really know what to pass... I'll show you my code which is taken from a Reto Meier example in Professional Android Development.
package com.virtualflyer.compass;
import...
public class MainActivity extends View {
public MainActivity(Context context){
super(context);
initCompassView();
}
public MainActivity(Context context, AttributeSet attrs){
super (context, attrs);
initCompassView();
}
public MainActivity(Context context,AttributeSet attrs,int defaultstyle){
super (context, attrs,defaultstyle);
initCompassView();
}
private Paint markerPaint;
private Paint textPaint;
private Paint circlePaint;
private String northString;
private String southString;
private String westString;
private String eastString;
private int textHeight;
protected void initCompassView(){
setFocusable(true);
Resources r=this.getResources();
circlePaint=new Paint (Paint.ANTI_ALIAS_FLAG);
circlePaint.setColor(r.getColor(R.color.background_color));
circlePaint.setStrokeWidth(1);
circlePaint.setStyle(Paint.Style.FILL_AND_STROKE);
northString=r.getString(R.string.cardinal_north);
southString=r.getString(R.string.cardinal_south);
eastString=r.getString(R.string.cardinal_east);
westString=r.getString(R.string.cardinal_west);
textPaint= new Paint (Paint.ANTI_ALIAS_FLAG);
textPaint.setColor(r.getColor(R.color.text_color));
textHeight=(int)textPaint.measureText("yY");
markerPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
markerPaint.setColor(r.getColor(R.color.marker_color));
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
int measuredWidth=measure(widthMeasureSpec);
int measuredHeight=measure(heightMeasureSpec);
int d =Math.min(measuredWidth,measuredHeight);
setMeasuredDimension(d,d);
}
private int measure(int measureSpec){
int result=0;
int specMode=MeasureSpec.getMode(measureSpec);
int specSize=MeasureSpec.getSize(measureSpec);
if (specMode==MeasureSpec.UNSPECIFIED){
result=200;
} else {
result=specSize;
}
return result;
}
private float bearing;
public void setBearing (float _bearing){
bearing=_bearing;
sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED);
}
public float getBearing(){
return bearing;
}
#Override
public boolean dispatchPopulateAccessibilityEvent(final AccessibilityEvent event){
super.dispatchPopulateAccessibilityEvent(event);
if (isShown()){
String bearingStr= String.valueOf(bearing);
if (bearingStr.length()>AccessibilityEvent.MAX_TEXT_LENGTH)
bearingStr=bearingStr.substring(0,AccessibilityEvent.MAX_TEXT_LENGTH);
event.getText().add(bearingStr);
return true;
}
else{
return false;
}
}
#Override
protected void onDraw(Canvas canvas){
int mMeasuredHeight=getMeasuredHeight();
int mMeasuredWidth=getMeasuredWidth();
int px= mMeasuredWidth/2;
int py=mMeasuredHeight/2;
int radius=Math.min(px,py);
canvas.drawCircle(px,py,radius,circlePaint);
canvas.save();
canvas.rotate(-bearing,px,py);
int textWidth=(int)textPaint.measureText("W");
int cardinalX=px-textWidth/2;
int cardinalY=py-radius+textHeight;
for (int i=0; i<24; i++){
canvas.drawLine(px,py-radius,px,py-radius+10,markerPaint);
canvas.save();
canvas.translate(0,textHeight);
if (i%6==0){
String dirString ="";
switch (i){
case(0) :{
dirString=northString;
int arrowY=2*textHeight;
canvas.drawLine(px,arrowY,px-5,3*textHeight,markerPaint);
break;
}
case(6) :dirString=eastString;break;
case(12) :dirString=southString;break;
case(18) :dirString=westString;break;
}
canvas.drawText(dirString, cardinalX,cardinalY,textPaint);
}
else if (i%3==0){
String angle =String.valueOf(i*15);
float angleTextWidth=textPaint.measureText(angle);
int angleTextX=(int) (px-angleTextWidth/2);
int angleTextY=(int) py-radius+textHeight;
canvas.drawText(angle,angleTextX,angleTextY,textPaint);
}
canvas.restore();
canvas.rotate(15,px,py);
}
canvas.restore();
}
}

I don't know what you are doing, but this might be the problem:
Why are you naming your class extended from View an Activity? If you have a MainActivity, you generally want to extend that from Activity class.
The problem might be there, that you declare in your manifest file that you have an Activity as MainActivity, but you don't because you extended that from View.
Here's what you do:
public class MainActivity extends Activity{ ... }
public class MyView extends View { /*insert your View code from above*/ }
and in MainActivity you might try
setContentView(new MyView(this));
And in the AndroidManifest you declare (I guess you had the same here or like it)
<activity
android:name=".MainActivity"
android:label="MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>