android - 如何在运行时更改 android 应用程序主题？

Question

我正在尝试在运行时更改我的应用主题
我有我的 ChangeTheme 类和 Utility(SharedPreferences) 类

ChangeTheme.java

public class ChangeTheme extends AppCompatActivity {

    private final static int THEME_LIGHT = 1;
    private final static int THEME_DARK = 2;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.change_theme_activity);
        updateTheme();
    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.myoptions,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        int id = item.getItemId();

        switch (id){
            case R.id.theme:
                Intent toChangeTheme = new Intent(ChangeTheme.this,ChangeTheme.class);
                startActivity(toChangeTheme);
        }

        return true;
    }

    public void onRadioButtonClicked(View view) {
        // Is the button now checked?
        boolean checked = ((RadioButton) view).isChecked();

        // Check which radio button was clicked
        switch(view.getId()) {
            case R.id.lightTheme:
                if (checked){
                    setTheme(R.style.AppTheme);
                }

                    break;
            case R.id.darkTheme:
                if (checked){
                    setTheme(R.style.AppThemeDark);
                }

                    break;
        }
    }

    public void updateTheme() {
        if (Utility.getTheme(getApplicationContext()) <= THEME_LIGHT) {
            setTheme(R.style.AppTheme);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
                getWindow().setStatusBarColor(getResources().getColor(R.color.colorPrimary));
            }
        } else if (Utility.getTheme(getApplicationContext()) == THEME_DARK) {
            setTheme(R.style.AppThemeDark);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                getWindow().addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
                getWindow().setStatusBarColor(getResources().getColor(R.color.colorSecondary));
            }
        }
    }

}

change_theme_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingTop="12dp"
    android:paddingLeft="8dp"
    android:paddingRight="8dp">

    <TextView
        android:id="@+id/textTheme"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Change Theme To:"
        android:layout_marginTop="125dp">
    </TextView>

    <RadioGroup
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginTop="20dp">
        <RadioButton
            android:id="@+id/lightTheme"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Light Theme"
            android:onClick="onRadioButtonClicked"/>
        <RadioButton
            android:id="@+id/darkTheme"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Dark Theme"
            android:onClick="onRadioButtonClicked"/>
    </RadioGroup>

</LinearLayout>

Utility.java

public class Utility {
    public static void setTheme(Context context, int theme) {
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
        prefs.edit().putInt(context.getString(R.string.prefs_theme_key), theme).apply();
    }
    public static int getTheme(Context context) {
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
        return prefs.getInt(context.getString(R.string.prefs_theme_key), -1);
    }
}

styles.xml

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="AppThemeDark" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorSecondary</item>
        <item name="colorPrimaryDark">@color/colorSecondaryDark</item>
        <item name="colorAccent">@color/colorSecondaryAccent</item>
    </style>

</resources>

当我单击按钮更改主题时没有任何 react ，为什么？
你能帮助我吗？
我已经检查过类似的问题，但没有任何帮助
更新 2020/09/08

ChangeTheme.java

public class ChangeTheme extends AppCompatActivity {

    private final static int THEME_LIGHT = 1;
    private final static int THEME_DARK = 2;
    private RadioButton lightThemeButton;
    private RadioButton darkThemeButton;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.change_theme_activity);

        lightThemeButton = (RadioButton) findViewById(R.id.lightTheme);
        darkThemeButton = (RadioButton) findViewById(R.id.darkTheme);
    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.myoptions,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        int id = item.getItemId();

        switch (id){
            case R.id.theme:
                Intent toChangeTheme = new Intent(ChangeTheme.this,ChangeTheme.class);
                startActivity(toChangeTheme);
        }

        return true;
    }

    public void onRadioButtonClicked(View view) {
        // Is the button now checked?
        boolean checked = ((RadioButton) view).isChecked();

        // Check which radio button was clicked
        switch(view.getId()) {
            case R.id.lightTheme:
                if (checked){
                    Utility.changeToTheme(this, Utility.THEME_LIGHT);
                }
                break;
            case R.id.darkTheme:
                if (checked){
                    Utility.changeToTheme(this, Utility.THEME_DARK);
                }
                break;
        }
    }
}

Utility.java

public class Utility {

    private static int sTheme;
    public final static int THEME_LIGHT = 0;
    public final static int THEME_DARK = 1;

    //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();
        activity.startActivity(new Intent(activity, activity.getClass()));
    }

    //Set the theme of the activity, according to the configuration. */
    public static void onActivityCreateSetTheme(Activity activity)
    {
        switch (sTheme)
        {
            default:
            case THEME_LIGHT:
                activity.setTheme(R.style.AppTheme);
                break;
            case THEME_DARK:
                activity.setTheme(R.style.DarkTheme);
                break;
        }
    }
}

styles.xml

<color name="color_primary_grey">#212121</color>
<color name="color_primary_black">#000000</color>
<color name="color_accent_white">#aeaeae</color>

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

<style name="DarkTheme" parent="AppTheme">
    <item name="colorPrimary">@color/color_primary_grey</item>
    <item name="colorPrimaryDark">@color/color_primary_black</item>
    <item name="colorAccent">@color/color_accent_white</item>
</style>

我现在必须做什么才能在运行时更改主题？

Answer 1

我之前为我的应用程序这样做过。
对于我的解决方案，我遵循了 this guide 中介绍的方法.
以下是要采取的步骤:

在共享首选项中保留主题的名称(或 ID)。你已经这样做了

在您的 Activity 的 onCreate 方法中获取应该应用的主题的字符串/ID(在样式中定义)，如下所示:

        // inside activities onCreate method
        // Within your switch command each case should look like this
        theme.applyStyle(R.style.AppColorsDefault, true) // in Java it should be getTheme()
        // for other cases just replace the style
        theme.applyStyle(R.style.AppColorsDark, true) // true forces overwriting attributes that are -potentially - defined by your AppTheme 

重新启动您的 Activity 以使您的更改生效(主题只能在您的 onCreate 方法中设置，因此您需要重新启动您的 Activity )

        val intent = requireActivity().intent // use Intent intent = getActivity().getIntent() in Java
        intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION)
        requireActivity().finish() // use getActivity() again
        startActivity(intent)

在我的解决方案中，您也不需要继承主题。应用的样式只需要包含更改。
这里有一个例子:
样式文件

<resources>

    <!-- Base application theme. 
         Also consider using a Material Theme
         Theme.MaterialComponents.Light.DarkActionBar
    -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <!-- put all the attributes here that should be applied to the app independent from the applied colors -->
    </style>

    <style name="AppColorsDefault">
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>


    <style name="AppColorsDark">
        <item name="colorPrimary">@color/colorSecondary</item>
        <item name="colorPrimaryDark">@color/colorSecondaryDark</item>
        <item name="colorAccent">@color/colorSecondaryAccent</item>
    </style>

</resources>

如果您的应用程序有多个 Activity ，并且您希望将更改的样式(例如颜色)应用于所有 Activity :
只需创建 BaseActivity那个 extends AppCompatActivity并让您的所有 Activity 扩展此 BaseActivity