Android - 使用 toast 确认应用程序退出

Question

我是 Android 开发的新手，我想要它，所以当用户在主要 Activity 上按下后退按钮时，会出现一条 toast 消息，其中包含“再次按下后退按钮确认退出”消息。我该怎么做？这是我目前所拥有的:

@Override
public void onBackPressed() {
    // TODO Auto-generated method stub
    super.onBackPressed();
    Toast s = Toast.makeText(getBaseContext(), "Press back again to exit", Toast.LENGTH_LONG);
    s.show();
    wait();

    public boolean onBackPressed() {
        finish();    
    }
}

Answer 1

我只会保存背压时间，然后将最新压机的时间与新压机的时间进行比较。

long lastPress;
@Override
public void onBackPressed() {
    long currentTime = System.currentTimeMillis();
    if(currentTime - lastPress > 5000){
        Toast.makeText(getBaseContext(), "Press back again to exit", Toast.LENGTH_LONG).show();
        lastPress = currentTime;
    }else{
        super.onBackPressed();
    }
}

您也可以在确认后退应用程序时关闭 toast (cred @ToolmakerSteve):

long lastPress;
Toast backpressToast;
@Override
public void onBackPressed() {
    long currentTime = System.currentTimeMillis();
    if(currentTime - lastPress > 5000){
        backpressToast = Toast.makeText(getBaseContext(), "Press back again to exit", Toast.LENGTH_LONG);
        backpressToast.show();
        lastPress = currentTime;
    } else {
        if (backpressToast != null) backpressToast.cancel();
        super.onBackPressed();
    }
}