Question

我一直在使用Callable，但现在我需要该函数在call方法中使用param。我知道这不是call的能力所以我怎么能这样做？

我目前有什么（错误的）：

AsyncTask async = new MyAsyncTask();
async.finished(new Callable(param) {
    // the function called during async.onPostExecute;
    doSomething(param);
});
async.execute(url);

MyAsyncTask：

...
@Override
protected void onPostExecute(JSONObject result)  {
    //super.onPostExecute(result);
    if(result != null) {
        try {
            this._finished.call(result); // not valid because call accepts no params
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

public void finished(Callable<Void> func) {
    this._finished = func;
}
...

Answer 1

如果您将param设为最终变量，则可以在Callable中引用它：

final String param = ...;
async.finished(new Callable() {
    // the function called during async.onPostExecute;
    doSomething(param);
});

当你创建 Callable时，你必须这样做 - 你以后不能给它值。如果由于某种原因需要它，你必须基本上使用共享状态 - Callable可以访问的某个“持有者”，以及在Callable执行之前可以设置值的“持有者” 。这可能只是MyAsyncTask本身：

final MyAsyncTask async = new MyAsyncTask();
async.finished(new Callable() {
    // the function called during async.onPostExecute;
    doSomething(async.getResult());
});
async.execute(url);

然后：

private JSONObject result;
public JSONObject getResult() {
    return result;
}

@Override
protected void onPostExecute(JSONObject result)  {
    this.result = result;
    if(result != null) {
        try {
            this._finished.call();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 2

我创建了一个像这样的新课程

import java.util.concurrent.Callable;

public abstract class ParamCallable<T> implements Callable<T> {
    public String Member; // you can add what you want here, ints, bools, etc.
}

然后你所要做的就是

ParamCallable<YourType> func = new ParamCallable<YourType>() {
    public YourType call() {
        // Do stuff.
        // Reference Member or whatever other members that you added here.
        return YourType;
    }
}

然后当你调用它时，设置你的数据并调用call（）

func.Member = value;
func.call();

传递使用param的android函数

2 个答案: