mainActivity.java
package com.mycompany.myapp;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.content.*;
import java.util.*;
public class MainActivity extends Activity
{
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
long Current =0;
//記錄上次按下返回的時間
public void onBackPressed(){
if (System.currentTimeMillis()- Current >2000){
Current=System.currentTimeMillis();
Toast.makeText(this,"再點擊一次推出",0).show();
}else{
finish();
System.exit(0);
}
//若是當前時間大於上次記錄的時間2秒,那麼點一次時彈出Toast消息,若是小於2s,那麼退出程序
}
}
Tony-Chen 2018.3.16