如何将Context传递给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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