Allow HTML5 video autoplay inside AgentWeb (closes #339)

[jim-daf]

Let HTML5 video autoplay inside AgentWeb

Closes #339

What changed

agentweb-core/src/main/java/com/just/agentweb/AbsAgentWebSettings.java

Call WebSettings.setMediaPlaybackRequiresUserGesture(false) from the default settings pipeline. Without this, every video.play() triggered by JavaScript on the loaded page was rejected by Chromium with the well-known message "play() can only be initiated by a user gesture", which is exactly what the reporter saw on the douyin reflow page.

The existing call to setMixedContentMode(MIXED_CONTENT_ALWAYS_ALLOW) already handles the "Mixed Content" half of the same trace. With both flags in place the same page now plays back normally.

Key snippet

mWebSettings.setJavaScriptCanOpenWindowsAutomatically(true);
mWebSettings.setMediaPlaybackRequiresUserGesture(false);

Notes

The flag is documented as having no effect for Web Audio in some Chromium versions. That is acceptable here because the issue is about HTML5 <video> playback. Apps that want to keep the Chromium default can override AgentWebSettingsImpl.toSetting and re-enable the gesture requirement.

[Copilot]

Pull request overview

Enables HTML5 video autoplay in AgentWeb by updating the default WebSettings configuration, addressing issue #339 where video.play() was blocked due to missing gesture exemptions.

Changes:

• Adds WebSettings.setMediaPlaybackRequiresUserGesture(false) to the default settings pipeline.
• Documents the motivation and context for the autoplay setting change inline.

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[Copilot]

WebSettings#setMediaPlaybackRequiresUserGesture was added in API 17. Since this module’s minSdkVersion is 14, calling it unconditionally can crash on API 14–16 with NoSuchMethodError. Please guard this call with a Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1 check (or equivalent) so older devices skip it safely.

Suggested change

	mWebSettings.setMediaPlaybackRequiresUserGesture(false);
	if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
	mWebSettings.setMediaPlaybackRequiresUserGesture(false);
	}

[Justson]

感谢贡献，但这个改动暂不合入，说明一下原因。

1. 缺少 API 版本守卫（会导致崩溃）

WebSettings.setMediaPlaybackRequiresUserGesture() 是 API 17 才引入的：

<method name="setMediaPlaybackRequiresUserGesture(Z)V" since="17"/>

而 agentweb-core 的 minSdkVersion 是 14。AbsAgentWebSettings#settings() 里对每一处受版本限制的调用都严格加了守卫（JELLY_BEAN / KITKAT / LOLLIPOP），唯独新增的这行没有，在 API 14~16 上会抛 NoSuchMethodError。项目 lint 配置了 abortOnError false，构建不会拦住它。

2. 更根本的问题：这是在替所有使用者改默认行为

这行代码会让每一个接入 AgentWeb 的 App 的 WebView 都开始允许自动播放（含声音）。这个副作用对流量、电量和用户体验的影响不小，不适合作为库的默认值。

而使用者现在就已经可以自行开启，不需要改库：

public IAgentWebSettings getSettings() {
    return new AbsAgentWebSettings() {
        @Override
        public IAgentWebSettings toSetting(WebView webView) {
            IAgentWebSettings settings = super.toSetting(webView);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
                settings.getWebSettings().setMediaPlaybackRequiresUserGesture(false);
            }
            return settings;
        }
        @Override protected void bindAgentWebSupport(AgentWeb agentWeb) { }
    };
}

如果希望做成库的一等能力，欢迎重开一个 PR，把它做成 AgentWeb.Builder 上的显式开关（默认保持关闭）并补上版本守卫，那样我很乐意合入。issue #339 暂时保持 open。

另外本 PR 与 #1085 内容重复（同一改动的两个位置），一并说明。