textviewArray[i].setText(stringArray[i]); is null

I created TextView Array and defined every element in array I got an a String array with intent but when I tried to set textview text with elements that received string array with for loop, it returned null
what is wrong with this codes? I am beginner in java and

public class dizilisActivity extends AppCompatActivity {
TextView player1, player2,player3,player4,player5,player6,player7,player8,player9,player10;
TextView[] players = {player1, player2,player3,player4,player5,player6,player7,player8,player9,player10};
String[] receivedNames;


protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dizilis);
    player1= (TextView) findViewById(R.id.player1);
    player2= (TextView) findViewById(R.id.player2);
    player3= (TextView) findViewById(R.id.player3);
    player4= (TextView) findViewById(R.id.player4);
    player5= (TextView) findViewById(R.id.player5);
    player6 = (TextView) findViewById(R.id.player6);
    player7 = (TextView) findViewById(R.id.player7);
    player8 = (TextView) findViewById(R.id.player8);
    player9 = (TextView) findViewById(R.id.player9);
    player10 = (TextView) findViewById(R.id.player10);
    Intent intent = getIntent();
    receivedNames = intent.getStringArrayExtra("names");
    for (int i = 0; i<receivedNames.length; ++i)
    players[i].setText(receivedNames[i]);

    }

}

and logcat

> Caused by: java.lang.NullPointerException: Attempt to invoke virtual
> method 'void android.widget.TextView.setText(java.lang.CharSequence)'
> on a null object reference
> at com.easoft.aldimverdim.dizilisActivity.onCreate(dizilisActivity.java:33)

and line 33 is

players[i].setText(receivedNames[i];

TL;DR

1. Change your
   from

TextView[] players = {player1, player2,player3,player4,player5,player6,player7,player8,player9,player10}

in to

TextView[] players;

2. Move initialization, so after

player10 = (TextView) findViewById(R.id.player10);

add:

players = new TextView[]{player1, player2, player3, player4, player5, player6, player7, player8, player9, player10};

3. When receivedNames will be null, you can add extra condition, for example:

// Check if receivedNames are NOT null
if (receivedNames != null) {
for (int i = 0; i < receivedNames.length; ++i) {
// here rest of codes
}
}

Error explanation

1. Line:

TextView player1, player2,player3,player4,player5,player6,player7,player8,player9,player10;

causes that 10 variables are declared. All of them are nulls

2. So in next line with:

TextView[] players = {player1, player2,player3,player4,player5,player6,player7,player8,player9,player10};

declare new array and initializes it with null values so you array with 10 nulls inside.

[null, null, null, null, null, null, null, null, null, null]

3. When in onCreate() you are trying to call players[i].setText(...), the players[i] has null value. So you call setText on null. That is the crash reason.

Full working code:

public class MainActivity extends AppCompatActivity {
TextView player1, player2, player3, player4, player5, player6, player7, player8, player9,
player10;
TextView[] players;
String[] receivedNames;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dizilis);
player1 = findViewById(R.id.player1);
player2 = findViewById(R.id.player2);
player3 = findViewById(R.id.player3);
player4 = findViewById(R.id.player4);
player5 = findViewById(R.id.player5);
player6 = findViewById(R.id.player6);
player7 = findViewById(R.id.player7);
player8 = findViewById(R.id.player8);
player9 = findViewById(R.id.player9);
player10 = findViewById(R.id.player10);
players = new TextView[]{player1, player2, player3, player4, player5, player6, player7,
player8, player9, player10};
Intent intent = getIntent();
receivedNames = intent.getStringArrayExtra("names");
if (receivedNames != null) {
for (int i = 0; i < receivedNames.length; ++i) {
players[i].setText(receivedNames[i]);
}
}
}
}

TIP #1

Good practice is to get index from shorter or "causing more problems", so you can change from:

i < receivedNames.length

to:

i < players.length

When you receive less data from getStringArrayExtra() = nothing happen (just empty TextViews).

But when you will try to assign to TextView which does not exist or to possition in array which does not exist = CRASH

TIP #2

If you will have same/similiar issue with loops you can:

• use breakpoints (about build Android app in debug mode`)
  or
• add simple try-catch block to check which index is causing problem. For example:

for (int i = 0; i < receivedNames.length; ++i) {
try {
players[i].setText(receivedNames[i]);
} catch (Exception e) {
System.out.println("Problem with id = " + i);
}
}

Seems like you are never updating the values in the array. Since you know you are going to have 10 views in the array try the following.

private final TextView[] views = new TextView[10];

protected void onCreate(Bundle savedInstanceState) {
   views[0] = (TextView) findViewById(R.id.player1);
   views[1] = (TextView) findViewById(R.id.player2);
   // ... and so forth
}

It seems you are first initializing the array with null references to text views and not updating the references there after like players[index]=(TextView) findViewById(R.id.player1). Instead of doing this ,create an empty array
and then use for loop for dynamically getting text view id and push object into the array.

public class dizilisActivity extends AppCompatActivity {
TextView[] players = new TextView[10];
String[] receivedNames;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dizilis);
for(int i=0;i<10;i++){
String textViewId="player"+(i+1);
int resID = getResources().getIdentifier(textViewId, "id", getPackageName());
players[i]=(TextView) findViewById(resID);
}
Intent intent = getIntent();
receivedNames = intent.getStringArrayExtra("names");
for (int i = 0; i<receivedNames.length; ++i)
players[i].setText(receivedNames[i]);
}