Jingtianer

如何选择页面展示的屏幕

1. Presentation – 指定display的Dialog

public class Presentation extends Dialog {
    public Presentation(Context outerContext, Display display) {
        this(outerContext, display, 0);
    }
}

• 本质是dialog

• 传入display

• Presentation 的上下文与其宿主 Activity 的上下文相互独立。加载布局、资源时必须使用 Presentation 自身的上下文进行布局填充与资源加载，才能保证加载出适配目标显示器尺寸、屏幕密度的资源素材。

public Presentation(@NonNull Context outerContext, @NonNull Display display, int theme,
            @WindowType int type) {
    super(createPresentationContext(outerContext, display, theme, type), theme, false);

    mDisplay = display;
    mDisplayManager = getContext().getSystemService(DisplayManager.class);

    final Window w = getWindow();
    final WindowManager.LayoutParams attr = w.getAttributes();
    w.setAttributes(attr);
    w.setGravity(Gravity.FILL);
    w.setType(getWindowType(type, display));
    setCanceledOnTouchOutside(false);
}

private static Context createPresentationContext(
            Context outerContext, Display display, int theme, @WindowType int type) {
    if (outerContext == null) {
        throw new IllegalArgumentException("outerContext must not be null");
    }
    if (display == null) {
        throw new IllegalArgumentException("display must not be null");
    }

    Context windowContext = outerContext.createDisplayContext(display)
            .createWindowContext(getWindowType(type, display), null /* options */);
    if (theme == 0) {
        TypedValue outValue = new TypedValue();
        windowContext.getTheme().resolveAttribute(
                com.android.internal.R.attr.presentationTheme, outValue, true);
        theme = outValue.resourceId;
    }
    return new ContextThemeWrapper(windowContext, theme);
}

• 当 Presentation 所依附的显示器被移除时，Presentation 会自动关闭（对应 Dialog.cancel()）。宿主 Activity 在自身执行暂停 / 恢复生命周期时，需要自行控制 Presentation 内部正在播放的内容，同步执行暂停、恢复操作。