时序图
2、目的
最终会生成一个RequestBuilder，这是一个通用请求构建类，把要用的参数放到RequestBuilder中比如最后一步就是把，load的参数丢到 model里，不管是String还是int。
//RequestManager.CLASS
public class RequestManager implements LifecycleListener,
ModelTypes<RequestBuilder<Drawable>> {
public RequestBuilder<Drawable> load(@Nullable String string) {
//这里调用 Drawable 图片加载请求器为其加载
return asDrawable().load(string);
}
public RequestBuilder<Drawable> asDrawable() {
return as(Drawable.class);
}
@NonNull
@CheckResult
@Override
public RequestBuilder<Drawable> load(@Nullable Uri uri) {
return asDrawable().load(uri);
}
@NonNull
@CheckResult
@Override
public RequestBuilder<Drawable> load(@Nullable File file) {
return asDrawable().load(file);
}
public <ResourceType> RequestBuilder<ResourceType> as(
@NonNull Class<ResourceType> resourceClass) {
return new RequestBuilder<>(glide, this, resourceClass,
context);
}
}
//RequestBuilder.CLASS
public class RequestBuilder<TranscodeType> extends
BaseRequestOptions<RequestBuilder<TranscodeType>>
implements Cloneable,
ModelTypes<RequestBuilder<TranscodeType>> {
public RequestBuilder<TranscodeType> load(@Nullable String
string) {
return loadGeneric(string);
}
// 描述加载的数据源-这里可以看做是我们刚刚传递进来的 http://xxxx.png
@Nullable private Object model;
// 描述这个请求是否已经添加了加载的数据源
private boolean isModelSet;
private RequestBuilder<TranscodeType> loadGeneric(@Nullable
Object model) {
this.model = model;
isModelSet = true;
return this;
}
}
