Question

在我的MainActivity中，我定义了：

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
//      int id = item.getItemId();
    switch (item.getItemId()) {
      case R.id.menu_settings:
        Toast.makeText(getApplicationContext(), "Settings menu clicked", Toast.LENGTH_LONG).show();
        Intent intent = new Intent(this, SettingsActivity.class);
        startActivity(intent);
        return true;
      case R.id.menu_location:
      startLocationUpdates();
      setupViewPager();
        return true;
      default:
        return super.onOptionsItemSelected(item);
    }
  }

Settings Activity是Android Studio创建的默认New->Activity->Settings，如下所示：

public class SettingsActivity extends AppCompatActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.settings_activity);
    getSupportFragmentManager()
        .beginTransaction()
        .replace(R.id.settings, new SettingsFragment())
        .commit();
    ActionBar actionBar = getSupportActionBar();
    if (actionBar != null) {
      actionBar.setDisplayHomeAsUpEnabled(true);
    }
  }

  public static class SettingsFragment extends PreferenceFragmentCompat {
    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
      setPreferencesFromResource(R.xml.root_preferences, rootKey);
    }
  }
}

现在，问题在于后退按钮实际上没有执行任何操作，即单击SettingsActivity上的后退按钮并不能将我带到MainActivity。

我该怎么办？

Answer 1

尝试在AndroidManifest.xml中设置父级活动：

 <activity
    android:name=".SettingsActivity"
    android:parentActivityName=".MainActivity">
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value=".MainActivity"/>
</activity>

Answer 2

尝试在Settings Activity上实施

 @Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
    if (item.getItemId() ==android.R.id.home) {
        finish();
    }
    return super.onOptionsItemSelected(item);
}
@Override
public void onBackPressed() {
    super.onBackPressed();
}

活动后退按钮没有任何作用

2 个答案: