上下文錯誤，同時將asynctask值傳遞給mainactivity

Question

在我的主要活動中，如果我應用此代碼，我得到錯誤gridviewadapter() cannot be applied,這是上下文中的問題。

GridViewAdapter adapter = new GridViewAdapter(this, R.layout.grid_item_layout, result); 

如果我申請這樣的：

public MainActivity (Context context) { 
     mContext = context; 

    } 
     GridViewAdapter adapter = new GridViewAdapter(mContext, R.layout.grid_item_layout, result); 

我在logcat的

java.lang.InstantiationException: can't instantiate class com.justedhak.www.i.MainActivity; no empty constructor 

我想傳遞的AsyncTask ArrayList的價值mainactivity這個錯誤..如何解決？

Answer 1

不應使用MainActivity類的構造函數。 請使用：的

GridViewAdapter adapter = new GridViewAdapter(getApplicationContext(), R.layout.grid_item_layout, result); 

代替：

GridViewAdapter adapter = new GridViewAdapter(this, R.layout.grid_item_layout, result); 

Answer 2

刪除此構造

public MainActivity (Context context) { 
    mContext = context; 
} 

添加此內部MainActivity的onCreate()

mContext = this; 

Answer 3

GridViewAdapter適配器=新GridViewAdapter（此，R.layout.grid_item_layout，列表項）;

Answer 4

嘗試

GridViewAdapter adapter = new GridViewAdapter(MainActivity.this, R.layout.grid_item_layout, result); 

Answer 5

如果你想傳遞mContext變量，初始化這個變量如下所示：

public class MainActivity extends AppCompatActivity { 
    private final Context mContext = this; 

    ... // other codes such as onCreate... 
} 

希望這有助於！