Android Button initialized but not working

Question

I have nine buttons in 3 X 3 grid for tic-tac-toe app. Here is the code from board_layout.xml for first three buttons -

<TableLayout
    android:id="@+id/tableLayout1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="20sp" >

    <TableRow
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center" >

        <Button
            android:id="@+id/cellOne"
            android:layout_width="90sp"
            android:layout_height="98sp"
            android:text=""
            android:textSize="70sp"
            />

        <Button
            android:id="@+id/cellTwo"
            android:layout_width="90sp"
            android:layout_height="98sp"
            android:text=""
            android:textSize="70sp"
            />

        <Button
            android:id="@+id/cellThree"
            android:layout_width="90sp"
            android:layout_height="98sp"
            android:text=""
            android:textSize="70sp"
            />

    </TableRow>

<!and so on for other 6>

Now in my MainActivity.java I have a function setboard() that sets this layout on this screen and initializes the buttons as follows:

private String p1name = "P1";
private String p2name = "P2";

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

public void setName(View view) {
            //Function called upon click on some button
            // Other code irrelevant to the question
            setBoard();
    }

}

public void setBoard() {
    ////////////
    LayoutInflater inflater = this.getLayoutInflater();
    View boardView = inflater.inflate(R.layout.board_layout, null);
    ////////////

    boardCells = new Button[3][3];
    boardCells[0][0] = (Button) boardView.findViewById(R.id.cellOne);
    boardCells[0][1] = (Button) boardView.findViewById(R.id.cellTwo);
    boardCells[0][2] = (Button) boardView.findViewById(R.id.cellThree);
    // Code for other 6 buttons

    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++) {
            boardCells[i][j].setOnClickListener(new MyClickListener(i, j));
            boardCells[i][j].setText("");
            boardCells[i][j].setEnabled(false);
        }

    setContentView(R.layout.board_layout);

    TextView tv1 = (TextView) findViewById(R.id.p1Name_board);
    tv1.setText(p1name + ":");

    tv1 = (TextView) findViewById(R.id.p2Name_board);
    tv1.setText(p2name + ":");

    turnDisp = (TextView) findViewById(R.id.turnDispString);
    turnDisp.setText("Turn of " + p1name);
}

Here is the code for MyClickListener class (inner class of MainActivity class):

class MyClickListener implements View.OnClickListener {
    int x;
    int y;


    public MyClickListener(int x, int y) {
        this.x = x;
        this.y = y;
        //This Log.d works fine
        Log.d("TAG1", Float.toString(x) + " " + Float.toString(y));
    }


    public void onClick(View view) {
        //This Log.d doesn't work
        Log.d("TAG2", Float.toString(this.x) + " Hi ");

        //This Toast also doesn't work
        Toast.makeText(getApplicationContext(), "Pressed", Toast.LENGTH_LONG).show();

        //Plus Other code irrelevant to the question
    }

Now the issue is that Log.d in constructor called while setting buttons is working fine and prints to Logcat but the onClick function doesn't works when the button is clicked. Neither the Log.d nor the toast is shown for onClick function.

Any help would be appreciated.

Answer 1

Short answer:

Your views aren't in the hierarchy

Long Answer / Solution (the right way to fix it):

You're seeing this problem because the views with your onClickListeners on aren't actually attached to the view hierarchy.

This could be easily avoided by never using a null in an inflater like you have here:

inflater.inflate(R.layout.board_layout, null);

It skips a useful block of code in the inflater anyway and there is already a provision for waiting to attach where you need to (i.e. in adapters):

inflater.inflate(R.layout.board_layout, parent, false);

When you pass null as the second parameter, the inflated views aren't attached to the hierarchy unless you manually do so.

However, in your case there is no need to inflate the layout. You're in an activity so setContentView() inflates and replaces the layout (but should never be called after onCreate).

Just change the layout being used in onCreate() and then remove the inflater.inflate and call findViewById directly on the context:

LayoutInflater inflater = this.getLayoutInflater(); View boardView = inflater.inflate(R.layout.board_layout, null);

boardCells[0][0] = (Button) findViewById(R.id.cellOne);

Also remove that second call to setContentView:

setContentView(R.layout.board_layout);

That second call was adding a new inflated set to the screen (not using the ones you attached a listener to)

There are also some other minor mistakes here. Java always uses Zero-based arrays (So the elements are [0],[1],[2]... not [1],[2]...). You're wasting memory with your board allocation - you have a 3x3 grid in your layout but a 4x4 array

boardCells = new Button[4][4];
boardCells[1][1] = (Button) boardView.findViewById(R.id.cellOne);

for (int i = 1; i <= 3; i++)
    for (int j = 1; j <= 3; j++)

When you use the loops above you're only using some items in the array (x's below). The zeros are empty wasted elements

0 | 0 | 0 | 0
- - - - - - -
0 | x | x | x
- - - - - - -
0 | x | x | x
- - - - - - -
0 | x | x | x

Another note (just to save you effort). Anytime you concatenate anything with a string, it will be cast to a string for you (primitives automatically, Objects automatically through their toString method), thus for logging the following are all equal:

Log.d("TAG1", Float.toString(x) + " " + Float.toString(y));
Log.d("TAG1", new Float(x) + " " + new Float(y));
Log.d("TAG1", x + " " + y);

Short Solution (a hack):

If, and only if, you didn't understand what I've just explained. Then you can fix it by changing

setContentView(R.layout.board_layout);

to

setContentView(boardView);

Answer 2

You should'nt use that code ,

boardCells[i][j].setOnClickListener(new MyClickListener(i, j));

I think , bugs starts from here.

You can ,

boardCells[i][j].setOnClickListener(new OnClickListener(....
Log.d("Testing","Clicked : " + i + "-" + j);
...)