Question

我的应用程序存在一些问题...我有一个设置活动，用户可以为应用程序选择主题，然后我有一个显示“返回”的按钮，并将用户返回到主活动。之后，主题得到了保存，一切正常。但我的问题是，如果用户点击“Android后退按钮”，我的主题不会被保存。有办法解决它吗？

这是我的设置活动：

public class SettingsActivity extends Activity implements OnClickListener {

public static final String PREF_NAME = "MyPrefsFile";
public static int newTheme;
public final static int THEME_DARK = R.style.DarkTheme;
public final static int THEME_LIGHT = R.style.LightTheme;
public final static int THEME_COLORS = R.style.ColorsTheme;
public final static int THEME_PERF = R.style.Performance;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    SharedPreferences settings = getSharedPreferences(PREF_NAME, MODE_PRIVATE);
    newTheme = settings.getInt("themeCustom", 0);   

     if(newTheme == THEME_DARK) {
        setTheme(R.style.DarkTheme);

    } else if(newTheme == THEME_LIGHT){
        setTheme(R.style.LightTheme);
    } else if(newTheme == THEME_COLORS) {
        setTheme(R.style.ColorsTheme);
    } else { 
        setTheme(R.style.Performance);
     }
    setContentView(R.layout.activity_settings);

    findViewById(R.id.button2).setOnClickListener(this);
    findViewById(R.id.button3).setOnClickListener(this);
    findViewById(R.id.button4).setOnClickListener(this);
    findViewById(R.id.button5).setOnClickListener(this);
    findViewById(R.id.button6).setOnClickListener(this);
}   
@Override
public void onClick(View v) {
    SharedPreferences settings = getSharedPreferences(PREF_NAME, MODE_PRIVATE);
    SharedPreferences.Editor edit;
    edit = settings.edit();
    Intent intent = getIntent();
    Intent main = new Intent(SettingsActivity.this,MainActivity.class);
    switch (v.getId()) {
    case R.id.button2:
        newTheme = THEME_DARK;
        edit.clear();
        edit.putInt("themeCustom", newTheme);
        edit.commit();
        finish();
        startActivity(intent);
        break;          
    case R.id.button3:
        newTheme = THEME_LIGHT;
        edit.clear();
        edit.putInt("themeCustom", newTheme);
        edit.commit();
        finish();
        startActivity(intent);
        break;
    case R.id.button5:
        newTheme = THEME_COLORS;
        edit.clear();
        edit.putInt("themeCustom", newTheme);
        edit.commit();
        finish();
        startActivity(intent);
        break;
    case R.id.button6:
        newTheme = THEME_PERF;
        edit.clear();
        edit.putInt("themeCustom", newTheme);
        edit.commit();
        finish();
        startActivity(intent);
        break;
    case R.id.button4:
        startActivity(main);
        break;
    default:
        break;
        }       
    }       
    }

非常感谢!! :)

Answer 1

您可以使用onBackpressed()

public void OnBackpressed()
{
// do stuff ( same as what you did in your button click)
}

当活动检测到用户按下后退键时调用。默认实现只是完成当前活动，但您可以覆盖它以执行任何操作。

Answer 2

你应该覆盖onBackPressed（）方法

@Override
public void onBackPressed() {
    super.onBackPressed();
    // to do
}

Answer 3

@Override
public void onBackPressed() {
   //do whatever to save the settings
   super.onBackPressed();
}

这样你就可以在按钮上做任何你想做的事情+它的初衷。

Answer 4

您可以使用以下方式

@Override
    public void onBackPressed() {
        // TODO Auto-generated method stub
        super.onBackPressed();
        SharedPreferences settings = getSharedPreferences("PREFS_NAME", 0);
        SharedPreferences.Editor editor = settings.edit();
        editor.putInt("themeCustom", newTheme);
        editor.commit();
    }

使用后退按钮保存sharedPreferences

4 个答案: