未调用OnClick方法

Question

here is my code:

public class MainActivity extends Activity implements View.OnClickListener {

    Button b;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b = (Button) findViewById(R.id.button1);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.button1:
                Toast.makeText(getApplicationContext(), "onClick method was called", Toast.LENGTH_LONG).show();
                break;
            }
        }
    }

For some reason nothing happens and no toast shows up. Did I miss anything ? Thanks

Answer 1

write:

b.setOnClickListener(this);

in onCreate :

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    b = (Button) findViewById(R.id.button1);
    b.setOnClickListener(this);
    }

you must set a listener to the button for onClick to work

Answer 2

As an alternative of Vipul answer you can also add the attribute onClick in the Button tag in the XML layout file. Example:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="myMethod" />

</RelativeLayout>

And, in your MainActivity.java, remove the View.OnClickListener implemented interface (thanks @donfuxx) add the following method:

public void myMethod(View v) {
    //do something
}