如何将Context传递给AsyncTask？ [英] How to pass Context to AsyncTask?

问题描述

如何在 Async Task 类中传递上下文，该类在主要活动的不同java文件中编码但是它被调用来自主要活动？

How to pass context in Async Task class which is coded in different java file from Main Activity but it called from main activity?

以下是我的代码：

 @Override

protected void onPostExecute(List<Movie_ModelClass> result) {
        super.onPostExecute(result);

        if (result != null) {
            Movie_Adapter movieAdapter = new Movie_Adapter(new MainActivity().getApplicationContext() , R.layout.custom_row, result);
            MainActivity ovj_main = new MainActivity();
            ovj_main.lv_main.setAdapter(movieAdapter);
        } else {
            Toast.makeText(new MainActivity().getApplicationContext() ,"No Data Found", Toast.LENGTH_LONG);

        }
        if (progressDialog.isShowing()) {
            progressDialog.dismiss();
    }

推荐答案

你可以传递一个 Context 实例作为构造函数参数（并保留 WeakReference 以避免内存泄漏）。

You could just pass a Context instance as a constructor parameter (and keep a WeakReference to it to avoid memory leaks).

例如：

public class ExampleAsyncTask extends AsyncTask {
    private WeakReference<Context> contextRef;

    public ExampleAsyncTask(Context context) {
        contextRef = new WeakReference<>(context);
    }

    @Override
    protected Object doInBackground(Object[] params) {
        // ...
    }

    @Override
    protected void onPostExecute(Object result) {
        Context context = contextRef.get();
        if (context != null) {
            // do whatever you'd like with context
        }
    }
}

执行：

new ExampleAsyncTask(aContextInstance).execute();

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