如果语句给出条件总是为真 [英] If statement gives condition is always true

问题描述

当我使用 if 语句时，它告诉我条件 x 始终为真，尽管我在另一个应用程序中使用相同的代码并且它有效，但在这种情况下我在 onOptionsItemSelected 中使用它 我的菜单的方法，有人可以帮忙吗?

When I use if statement it gives me that the condition x is always true although I use the same code in another app and it works, but in this case I use it in onOptionsItemSelected method for my menu ,So can someone help ?

public class Wellcome extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_wellcome);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

        }

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.chang_language, menu);
    return true;
}
 Boolean x=true;
@Override
public boolean onOptionsItemSelected(MenuItem item) {
   int id = item.getItemId();
   if (id == R.id.arabic) {
       if (x =true) {
           setLocale("en");
           x = false;
       } else  if (x =false) {
           setLocale("ar");
           x = true;
       }
     return true;
   }
    return super.onOptionsItemSelected(item);
}
public void setLocale(String lang) {
    java.util.Locale myLocale = new Locale(lang);
    DisplayMetrics dm = getResources().getDisplayMetrics();
    Configuration conf = getResources().getConfiguration();
    conf.locale = myLocale;
    getResources().updateConfiguration(conf, dm);
    Intent refresh = new Intent(this, Wellcome.class);
    startActivity(refresh);
       }
     }

推荐答案

绕过比较运算符错误 = 而不是 == (==> 是正确的，请更新您的代码)，这是从其他答案中解决的，您的程序流程导致永远不会到达(至少是用户体验部分)您设置 x 的部分if 语句中的 false 变量.

Bypassing the comparison operator error = instead of == (== is the correct, please update your code), which is addressed from the other answers, the flow of your program leads to never reach (at least the user experience part) the part where you set the x variable to false in the if statement.

setLocale("en");
x = false; // -> this part is not reached because you start a new activity of the same class in the setLocale above

更具体地说，在 onOptionsItemSelected 方法中调用的 setLocale 方法通过以下代码重新启动您的活动:

More specifically, the setLocale method which is called in the onOptionsItemSelected method, restarts your activity via the following code:

Intent refresh = new Intent(this, Wellcome.class);
startActivity(refresh);

由于 Wellcome 活动是从 refresh 意图开始的，一个新的 Wellcome 活动会出现在旧的活动之上，当然这个新活动的字段变量 x 将被实例化为 true,

Since the Wellcome activity is started from the refresh intent, a new Wellcome activity appears on top of the old one, and of course this new activity's field variable x will be instantiated to true,

Boolean x=true;

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