Question

in an android app , I use menus for an activity

<menu
  xmlns:android="http://schemas.android.com/apk/res/android">
  <item 
  android:id="@+id/logout"
  android:title="Logout" />
  <item 
  android:id="@+id/compose"
  android:title="Compose"  />
  <item 
  android:id="@+id/refresh"
  android:title="Refresh" />
</menu>

and in activity :

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.inboxmenu, menu);
    return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
    case R.id.logout:
        SharedPreferences settings =getSharedPreferences("CASPreferences", MODE_PRIVATE);
        SharedPreferences.Editor prefEditor = settings.edit();
        prefEditor.putString("uid", "");
        prefEditor.putString("stdno", "");
        prefEditor.putString("firstname", "");
        prefEditor.putString("lastname", "");
        prefEditor.putString("lastname", "");
        prefEditor.commit();
        Intent myIntent = new Intent(this, LoginActivity.class);
        startActivity(myIntent);
        return true;
    case R.id.refresh:
        Log.e("menu" , "refresh");
        //Intent intent=new Intent(this,MainActivity.class);
        startActivity(getIntent());
        finish();
    case R.id.compose:
        Log.e("menu" , "compose");
        Intent intent1=new Intent(this,ComposeActivity.class);
        startActivity(intent1);




    default:
        return super.onOptionsItemSelected(item);
    }
}

but when I click on refresh button , it goes to compose activity ! like as you clicked on compose.

why does this happen?

Answer 1

Rewrite your switch statement.

switch (item.getItemId()) {
case R.id.logout:
    ...
    return true;
case R.id.refresh:
    ...
    finish();
    break; // <- Add this line
case R.id.compose:
    ...
    break; // <- Add this line
default:
    return super.onOptionsItemSelected(item);
}

Each case block must be enclosed by break.

The break statements are necessary because without them, statements in switch blocks fall through: All statements after the matching case label are executed in sequence, regardless of the expression of subsequent case labels, until a break statement is encountered.

break doesn’t required in first case block because flow interrupted by return statement.

Reference: http://download.oracle.com/javase/tutorial/java/nutsandbolts/switch.html