Android基础TOP4_1：点击物理按钮弹出退出提示框

public class MainActivity extends Activity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); }
//点击物理按钮时，执行退出提示
public boolean onKeyDown(int keyCode,KeyEvent event){
if(keyCode==KeyEvent.KEYCODE_BACK && event.getRepeatCount()==){
creatdialog();
}
return false;
}private void creatdialog() {
// TODO Auto-generated method stub
AlertDialog.Builder b=new Builder(MainActivity.this);
//设置提示框内容
b.setMessage("确认退出么");
//设置标题栏
b.setTitle("提示");
b.setPositiveButton("确认",new OnClickListener() { public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
//点确定时退出程序,并隐藏此对话框
dialog.dismiss();
MainActivity.this.finish();
}
}).setNegativeButton("取消",new OnClickListener() { @Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
//点击取消时只隐藏对话框
dialog.dismiss();
}
});
b.create().show();
}}