Question

I’m new to android development, and haven’t programmed GUI’s in java yet so button work is all new to me.

I’m making a simple hello world app, has some buttons/radios/checkboxes etc. We have to figure out a way to make it nice, there is nothing specific in the brief. so I figured I’d get some buttons and show the different kinds of toast, maybe change the background etc.

so I implemented a toast based off a tutorial, but it works on all of the instantiated buttons instead of just the one I want. I would like the other button to do something else.

I think it has to do with the onClickListener, but beyond that I’m stuck.

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        btn1 = (Button) findViewById(R.id.button1);
        btn1.setOnClickListener(this);

        btn2 = (Button) findViewById(R.id.button2);
        btn2.setOnClickListener(this);


        cb=(CheckBox)findViewById(R.id.check);
        cb.setOnCheckedChangeListener(this);

        browser=(WebView)findViewById(R.id.webkit);
        browser.loadUrl("http://www.google.com/search");

        }


    public void onClick(View v) {
        new AlertDialog.Builder(this).setTitle("MessageDemo").setMessage(
                "This is an Alert Dialogue Toast").setNeutralButton(
                "Here, here!", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dlg, int sumthin) {
                        Toast.makeText(HelloWorldActivity.this,
                                "<clink, clink>", Toast.LENGTH_SHORT).show();
                    }
                }).show();
    }

and here’s the xml for the buttons

 <Button android:id="@+id/button1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Testa" 
    android:layout_weight="0.2"></Button>

Answer 1

You’ve added the same onClickListener to each button so they will have the same behavior. You can actually create the listener right inside the setOnClickListener call, like this:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    btn1 = (Button) findViewById(R.id.button1);
    btn1.setOnClickListener( new OnClickListener() {
        public void onClick(View v) {
            new AlertDialog.Builder(this).setTitle("MessageDemo").setMessage(
                "This is an Alert Dialogue Toast").setNeutralButton(
                "Here, here!", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dlg, int sumthin) {
                        Toast.makeText(HelloWorldActivity.this,
                            "<clink, clink>", Toast.LENGTH_SHORT).show();
                    }
            }).show();            
        }
    });

    btn2 = (Button) findViewById(R.id.button2);
    btn2.setOnClickListener( new OnClickListener() {
        public void onClick(View v) {
            // Do something different here.
        }
    });

    // The rest of onCreate
}

EDIT: I’ve updated the answer to make it clear which parts of your original code would go where, but I usually wouldn’t stick a big chunk of code like that inside of the onClick as it’s not very readable. I’d prefer something more like this:

public void onCreate(Bundle savedInstanceState) {
   // other onCreate code
    btn1 = (Button) findViewById(R.id.button1);
    btn1.setOnClickListener( new OnClickListener() {
        public void onClick(View v) {
            showBtn1ClickedDialog();
        }
    });
   // other onCreate code
}

private void showBtn1ClickedDialog() {
    new AlertDialog.Builder(this).setTitle("MessageDemo").setMessage(
        "This is an Alert Dialogue Toast").setNeutralButton(
        "Here, here!", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dlg, int sumthin) {
                Toast.makeText(HelloWorldActivity.this,"<clink, clink>", Toast.LENGTH_SHORT).show();
            }
    }).show();            
}