I am new to Android Programming. In my application I am inserting data to 2 SQLite database tables teams and teams_vs_leagues. Directly following an insert I want to go to a new activity to view and edit the data from the insert. I used similar code in another Class but I was passing the position of an item in a ListView onClickListener and when I try to pass the id on a Button onClickListener I am receiving the error below.
Process: com.example.android.soccerleaguesapp, PID: 14919
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.soccerleaguesapp/com.example.android.soccerleaguesapp.DisplayTeam}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2344)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2404)
at android.app.ActivityThread.access$800(ActivityThread.java:145)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5319)
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:1016)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:811)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
at com.example.android.soccerleaguesapp.DisplayTeam.onCreate(DisplayTeam.java:36)
at android.app.Activity.performCreate(Activity.java:5976)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2297)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2404)
at android.app.ActivityThread.access$800(ActivityThread.java:145)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5319)
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:1016)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:811)
addTeam method
public void addTeam() {
//set onclick method on add_team button
add_team.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
//Call Team class and declare insert values for createTeam method
Team team = new Team();
team.setTeamName(team_name.getText().toString());
team.setPath(picturePath);
team.setLeague_id(leagueIdParse);
//set long as the id of insert, used to pass into intent
long id = myDb.createTeam(team);
//Toast message to show that team has been successfully added
Toast.makeText(add_team.this, team_name.getText().toString() + " successfully added", Toast.LENGTH_SHORT).show();
Intent intent =
new Intent(add_team.this, DisplayTeam.class);
intent.putExtra("TEAM", (new Gson()).toJson(id));
startActivity(intent);
}
}
);
}
createTeam method
public long createTeam(Team team) {
//Create SQLiteDatabase instance
SQLiteDatabase db = this.getWritableDatabase();
//setup values variable to be passed in insert to teams table
ContentValues values = new ContentValues();
//values of each column to be inserted into table from argument strings
values.put(TEAM_NAME, team.getTeamName());
values.put(IMAGE, team.getPath());
//insert values into teams table
long result = db.insert(TEAMS_TABLE, null, values);
//new ContentValues instance for values to passed in insert into teams_vs_leagues table
ContentValues newValues = new ContentValues();
//values of each column to be inserted into table from argument strings
newValues.put(TEAM_ID, result);
newValues.put(LEAGUE_ID, team.getLeagueId());
newValues.put(POINTS, 0);
//insert values into teams_vs_leagues table
long newResult = db.insert(TEAMS_VS_LEAGUES_TABLE, null, newValues);
return result;
DisplayTeam class
public class DisplayTeam extends AppCompatActivity {
private Team team;
private ImageView imageView;
private TextView teamName;
private String jstring;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.display_team);
imageView = (ImageView) findViewById(R.id.display_image_view);
teamName = (TextView) findViewById(R.id.text_view_description);
Bundle extras = getIntent().getExtras();
if (extras != null) {
jstring = extras.getString("TEAM");
}
team = getTeam(jstring);
teamName.setText(team.toString());
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;
imageView.setImageBitmap(ImageResizer
.decodeSampledBitmapFromFile(team.getPath(), width, height));
}
private Team getTeam(String team) {
try {
JSONObject job = new JSONObject(team);
return (new Team(
job.getInt("id"),
job.getString("team_name"),
job.getString("path"),
job.getInt("league_id"),
job.getString("league_name")));
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* go back to add_gallery activity
*
* @param v
*/
public void btnBackOnClick(View v) {
startActivity(new Intent(this, add_team.class));
finish();
}
/**
* delete the current item;
*
* @param v
*/
public void btnDeleteOnClick(View v) {
DatabaseHelper db = new DatabaseHelper(this);
db.deleteTeam(team);
db.close();
startActivity(new Intent(this, add_team.class));
finish();
}
@Override protected void onSaveInstanceState(Bundle outState) {
// Save the user's current game state
if (jstring != null) {
outState.putString("jstring", jstring);
}
// Always call the superclass so it can save the view hierarchy state
super.onSaveInstanceState(outState);
}
@Override protected void onRestoreInstanceState(Bundle savedInstanceState) {
// Always call the superclass so it can restore the view hierarchy
super.onRestoreInstanceState(savedInstanceState);
// Restore state members from saved instance
if (savedInstanceState.containsKey("jstring")) {
jstring = savedInstanceState.getString("jstring");
}
}
}
Team class
public class Team {
private String team_name, path, league_name;
int id, league_id;
public Team(String team_name, String path,
int league_id) {
this.team_name = team_name;
this.path = path;
this.league_id = league_id;
}
public Team(String team_name, String path,
int league_id, String league_name) {
this.team_name = team_name;
this.path = path;
this.league_id = league_id;
this.league_name = league_name;
}
public Team(int keyId, String team_name, String path,
int league_id) {
this.id = keyId;
this.team_name = team_name;
this.path = path;
this.league_id = league_id;
}
public Team(int keyId, String team_name, String path,
int league_id, String league_name) {
this.id = keyId;
this.team_name = team_name;
this.path = path;
this.league_id = league_id;
this.league_name = league_name;
}
//empty constructor
public Team() {}
public Team(int keyId) {
this.id = keyId;
}
/**
* Gets id.
*
* @return Value of id.
*/
public int getId() {
return id;
}
// setting id
public void setId(int keyId) {
this.id = keyId;
}
/**
* Gets league_id.
*
* @return Value of league_id.
*/
public int getLeagueId() {
return league_id;
}
/**
* Gets team_name.
*
* @return Value of team_name.
*/
public String getTeamName() {
return team_name;
}
/**
* Gets league_name.
*
* @return Value of league_name.
*/
public String getLeagueName() {
return league_name;
}
/**
* Sets new team_name.
*
* @param team_name New value of team_name.
*/
public void setTeamName(String team_name) {
this.team_name = team_name;
}
/**
* Sets new league_id.
*
* @param league_id New value of league_id.
*/
public void setLeague_id(int league_id) {
this.league_id = league_id;
}
/**
* Sets new path.
*
* @param path New value of path.
*/
public void setPath(String path) {
this.path = path;
}
/**
* Gets path.
*
* @return Value of path.
*/
public String getPath() {
return path;
}
}
If you require any more information, do not hesitate to contact me. Any help would be greatly appreciated.
