我正在编写这段代码，它显示了错误非静态方法getID()无法从静态上下文引用。

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

Button greetbutton;

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

    greetbutton = (Button) findViewById(R.id.greetbutton);
    greetbutton.setOnClickListener(this);
}

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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@Override
public void onClick(View v) {

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

    EditText editFreindname = (EditText) findViewById(R.id.editFriendname);

    String freindname    = editFreindname.getText().toString();

    switch (View.getId()) {

        case R.id.greetbutton:

            textView.setText(getString(R.string.greetstring) + freindname + "!");

            break;

        default:

            break;
    }

}
}