问题描述
我有秒表应用。 我在主布局上有不同背景的 Switchcompat。 当我在运行时间时轻按开关时,它会重置为 00:00:00。
有没有办法不用重置定时器就可以使用开关?
这是代码的一些部分。
MainActivity
SwitchCompat switchCompat;
SharedPreferences sharedPreferences = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
switchCompat = findViewById(R.id.switchCompat);
sharedPreferences = getSharedPreferences("night",0);
Boolean booleanValue = sharedPreferences.getBoolean("NightMode",false);
if (booleanValue) {
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
switchCompat.setChecked(true);
}
switchCompat.setonCheckedchangelistener(new CompoundButton.OnCheckedchangelistener() {
@Override
public void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {
if (isChecked) {
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
switchCompat.setChecked(true);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putBoolean("NightMode",true);
editor.commit();
}else {
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
switchCompat.setChecked(false);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putBoolean("NightMode",false);
editor.commit();
}
}
});
}
解决方法
签出 saving instance state pattern - 存储时间值并在 Activity
重新创建时重新存储
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putString("SwitchText",switchCompat.getText().toString());
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
switchCompat = findViewById(R.id.switchCompat);
if (savedInstanceState != null) { // is null on first start
String switchText = savedInstanceState.getString("SwitchText");
// may be null when no value stored under given key
if (switchText != null) switchCompat.setText(switchText);
}
...
Activity
被重新创建/重新启动,因为在 onCheckedChanged
中您正在调用 AppCompatDelegate.setDefaultNightMode
- 这迫使 Activity
重新启动并应用新主题,您必须编写一些额外的保存之前状态的代码