java - 主要 Activity 未设置主题

Question

我正在尝试动态更改应用程序的主题。我有两项 Activity ，一项是主要 Activity ，另一项是设置 Activity 。

在设置 Activity 中，当选择颜色时，我将从颜色选择器对话框中更改主题，主题会更改。但主题仅针对设置 Activity 进行更改，而不针对主要 Activity 进行更改。

我尝试将颜色值从设置 Activity 发送到主 Activity ，但应用程序无法启动。它只显示空白屏幕。

当我进行调试时，我发现它卡在第一个 if(n==0){} 上，并且循环继续下去并没有结束。

不明白哪里出了问题。

当我来自设置 Activity 时，主要 Activity 也可能不会刷新。如何刷新主要 Activity ？

设置 Activity :

public class Settings extends AppCompatActivity {

    int no;

    public static final String MyPREFERENCES = "MyPrefs" ;
    public static final int color = 0;
    public static final int color_2 = 0;
    public static final int color_3 = 0;
    SharedPreferences sharedpreferences;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        Theme.onActivityCreateSetTheme(this);

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_settings);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);



        final ColorPickerDialog colorPickerDialog = new ColorPickerDialog();
        colorPickerDialog.initialize(R.string.dialog_title, new int[]{Color.CYAN, Color.LTGRAY, Color.BLACK, Color.BLUE, Color.GREEN, Color.MAGENTA, Color.RED, Color.GRAY, Color.YELLOW}, Color.YELLOW, 3, 2);
        colorPickerDialog.setOnColorSelectedListener(new ColorPickerSwatch.OnColorSelectedListener() {

            @Override
            public void onColorSelected(int color) {

                if (color == Color.CYAN) {
                    Theme.changeToTheme(Settings.this, Theme.THEME_DEFAULT);
                    no = 0;
                }
                else if (color == Color.LTGRAY)

                {
                    Theme.changeToTheme(Settings.this, Theme.THEME_WHITE);
                    no = 1;
                }
                else if (color == Color.BLACK) {

                    Theme.changeToTheme(Settings.this,Theme.THEME_BLUE);
                    no = 3;

                }
                Toast.makeText(Settings.this, "selectedColor : " + color, Toast.LENGTH_SHORT).show();
            }

        });

        SharedPreferences.Editor editor = sharedpreferences.edit();

        editor.putInt("color",no);
      //  editor.putInt("color_2",no);
      //  editor.putInt("color_3",no);
        editor.commit();

        LinearLayout theme = (LinearLayout)findViewById(R.id.theme);

        theme.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                colorPickerDialog.show(getSupportFragmentManager(), "colorpicker");
            }
        });
    }

}

主题:

    public class Theme {

    private static int sTheme;

    public final static int THEME_DEFAULT = 0;
    public final static int THEME_WHITE = 1;
    public final static int THEME_BLUE = 2;

    /** * Set the theme of the Activity, and restart it by creating a new Activity of the same type. */
    public static void changeToTheme(Activity activity, int theme) {
        sTheme = theme;
        activity.finish();
        Intent i = new Intent(activity,activity.getClass());
        activity.startActivity(i);
    }

    /** Set the theme of the activity, according to the configuration. */
    public static void onActivityCreateSetTheme(Activity activity) {
        switch (sTheme) {
            default:

            case THEME_DEFAULT:
                activity.setTheme(R.style.AppTheme);
                break;

            case THEME_WHITE:

                activity.setTheme(R.style.AppTheme_Solarized);
                break;

            case THEME_BLUE:

                activity.setTheme(R.style.BlueTheme);

                break;

        }
    }
}

主要 Activity :

public class MainActivity extends AppCompatActivity {

private NavigationView navigationView;
private DrawerLayout drawerLayout;
Toolbar mToolbar;
private MainFragment mFragment;
private int no,no1,no2;

@Override
protected void onCreate(Bundle savedInstanceState) {

   SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
    SharedPreferences.Editor editor = pref.edit();


    no = pref.getInt("color",0);


    if(no == 0)
    {
        setTheme(R.style.AppTheme);
    }

    else if(no == 1)
    {
        setTheme(R.style.AppTheme_Solarized);
    }

    else if(no == 2)
    {
        setTheme(R.style.BlueTheme);
    }

   // Theme.onActivityCreateSetTheme(this);

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

谢谢。

Answer 1

在您的Settings类中，您将选定的颜色写入“MyPrefs”首选项，但在您的MainActivity中，您正在从读取>“MyPref”(不带 S)偏好设置。

您已经拥有公共(public)常量 MyPREFERENCES，也尝试在 MainActivity 中使用它。