安卓应用程序级的字体大小preference

问题描述

是否有可能使一个应用程序范围内设置字体大小要使用的显示文本中的所有观点？ 我想提供一个preference到应该允许扩展应用程序中的所有文本的用户。

Is it possible to make an application-wide setting for the font-size to be used by all views displaying text? I would like to provide a Preference to the user which should allow scaling all text in the app.

Android的明确允许使用SP尺度单位可扩展的文本，但没有实际的方式来在全球的方法设置用户的字体大小preference。

Android explicitly allows using the "sp" dimension unit for scalable text, however there is no actual way to set the "user's font size preference" in a global way.

迭代通过活动的实例化所有视图是不是一个真正的选择; - ）

Iterating through all views on Activity instantiation is not really an option ;-)

推荐答案

这就是我做它为我的应用程序。 在几句话 - 在 Activity.onCreate（）你的风格和特定的字体大小的资源ID，并应用这种风格到活动的主题。然后用preferences活动，您可在这些集之间切换。

Here it's how I made it for my app. In a few words - in Activity.onCreate() you get resource id of style with specific set of font sizes and apply this style to theme of activity. Then with preferences activity you can switch between these sets.

首先在价值/ attrs.xml申报设置的字体大小的属性：

First of all in values/attrs.xml declare attributes for set of font sizes:

<declare-styleable name="FontStyle">
    <attr name="font_small" format="dimension" />
    <attr name="font_medium" format="dimension" />
    <attr name="font_large" format="dimension" />
    <attr name="font_xlarge" format="dimension" />
</declare-styleable>

然后在值/ styles.xml声明字体大小的几集：

Then in values/styles.xml declare few sets of font sizes:

<style name="FontStyle">
</style>

<style name="FontStyle.Small">
    <item name="font_small">14sp</item>
    <item name="font_medium">16sp</item>
    <item name="font_large">18sp</item>
    <item name="font_xlarge">20sp</item>
</style>

<style name="FontStyle.Medium">
    <item name="font_small">18sp</item>
    <item name="font_medium">20sp</item>
    <item name="font_large">22sp</item>
    <item name="font_xlarge">24sp</item>
</style>

<style name="FontStyle.Large">
    <item name="font_small">26sp</item>
    <item name="font_medium">28sp</item>
    <item name="font_large">30sp</item>
    <item name="font_xlarge">32sp</item>
</style>

然后在的onCreate（）的每一次活动的方法添加：

Then in onCreate() method of every activity add:

getTheme().applyStyle(new Preferences(this).getFontStyle().getResId(), true);

其中， preferences 是一个门面共享preferences 目标：

public class Preferences {
    private final static String FONT_STYLE = "FONT_STYLE";

    private final Context context;

    public Preferences(Context context) {
        this.context = context;
    }

    protected SharedPreferences open() {
        return context.getSharedPreferences("prefs", Context.MODE_PRIVATE);
    }

    protected Editor edit() {
        return open().edit();
    }

    public FontStyle getFontStyle() {
        return FontStyle.valueOf(open().getString(FONT_STYLE,
            FontStyle.Medium.name()));
    }

    public void setFontStyle(FontStyle style) {
        edit().putString(FONT_STYLE, style.name()).commit();
    }
}

和fontstyle的是：

and FontStyle is:

public enum FontStyle {
    Small(R.style.FontStyle_Small, "Small"), 
    Medium(R.style.FontStyle_Medium, "Medium"), 
    Large(R.style.FontStyle_Large, "Large");

    private int resId;
    private String title;

    public int getResId() {
        return resId;
    }

    public String getTitle() {
        return title;
    }

    FontStyle(int resId, String title) {
        this.resId = resId;
        this.title = title;
    }
}

和 FontStyle.values​​（）作为项目的微调在 preferencesActivity 。 这是我怎么是这样的：

And FontStyle.values() is used as items for Spinner in your PreferencesActivity. That's how mine looks like:

public class PreferencesActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    getTheme().applyStyle(new Preferences(this).getFontStyle().getResId(), true);
    super.onCreate(savedInstanceState);

    setContentView(R.layout.preferences);

    Preferences prefs = new Preferences(this);

    Spinner fontStylesView = (Spinner) findViewById(R.id.font_styles);
    FontStylesAdapter adapter = new FontStylesAdapter(this,
            R.layout.font_styles_row, FontStyle.values());
    fontStylesView.setAdapter(adapter);

    fontStylesView.setSelection(prefs.getFontStyle().ordinal());
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getSupportMenuInflater();
    inflater.inflate(R.menu.preferences, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.menu_done:
        onMenuDone();
        finish();
        return true;
    case R.id.menu_cancel:
        finish();
        return true;
    default:
        return false;
    }
}

private void onMenuDone() {
    Preferences prefs = new Preferences(this);

    Spinner fontStylesView = (Spinner) findViewById(R.id.font_styles);
    prefs.setFontStyle((FontStyle) fontStylesView.getSelectedItem());
}
}

最后，你可以用你的字体大小preferences：

And finally you can use your font size preferences:

<TextView android:textSize="?attr/font_large" />

或者我preFER使用样式，在值/ styles.xml补充：

Or I prefer using styles, in values/styles.xml add:

<style name="Label" parent="@android:style/Widget.TextView">
    <item name="android:textSize">?attr/font_medium</item>
    <item name="android:layout_width">wrap_content</item>
    <item name="android:layout_height">wrap_content</item>
</style>

<style name="Label.XLarge">
    <item name="android:textSize">?attr/font_xlarge</item>
</style>

你可以这样使用它：

And you can use it in this way:

<TextView style="@style/Label.XLarge" />

我希望我的回答可以帮助你。

I hope my answer will help you.