Android development Linking XML button to Java

Question

I am new to android development, I am basically trying to create a very basic app which will enable the user to switch on their wifi.

My XML file:

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Answer 1

There are several ways of doing this.

1. What you can do is add this line to your <Button tag in xml

   android:onClick="setWifiOn"

then change the parameter of that function to

public void getWifiOn(View v){


return wifi_on;

} 

with this you don't need the onClick or any listeners

2.You can do something similar if you want all Buttons to share the same function then give them all the function name like

android:onClick="someFunction"

then in Java do something like

public void someFunction(View v)
{
    Button btn = (Button)v;  
    switch (v.getId())
    {
       case (R.id.wifi_on:
        setWifiOn(btn);
        break;
       case (R.id.differentBtnId):
       // do some other things
       break;
     }
}

}

3.Less attractive in many situations, IMHO

    public class MainActivity extends Activity implements OnClickListener {
    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Button wifiBtn = (Button) findViewById(R.id.wifi_on);
    wifiBtn.setOnClickListener(this);  // your onClick below will be called then you will still have to check the id of the Button
    // multiple buttons can set the same listener and use a switch like above

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public void onClick(View v) {
    // TODO Auto-generated method stub

}

Note number 3 is the only one in which you need implements OnClickListener

Button Docs

I left out the other way because I think its the ugliest if you have more than one Button