布局代码：
菜单文件：
完整代码：
public class MainActivity extends Activity {
private TextView tvMsg;
private float fontSize = 15.0f;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvMsg = (TextView) findViewById(R.id.tv);
tvMsg.setTextSize(fontSize);
}
public void showPopup(View v){
//锚点
PopupMenu popup = new PopupMenu(this,v);
getMenuInflater().inflate(R.menu.main, popup.getMenu());
//显示菜单
popup.show();
//处理菜单项的点击事件
popup.setOnMenuItemClickListener(new OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_add:
fontSize+=5;
break;
case R.id.action_sub:
fontSize-=5;
break;
}
tvMsg.setTextSize(fontSize);
return false;
}
});
}
}