super.onActivityResult 内部适配器 class？ Android

Question

我的 RecyclerView 包含非常复杂的项目，多个 buttons/images/texts。为了访问每个 button/image，我在适配器 class.

中设置了点击监听器

但是现在我正在尝试添加设置联系人铃声的功能，但我遇到了问题。

我这样调用 onActivityResult 方法：

Intent contactIntent = new Intent(Intent.ACTION_PICK);
                contactIntent.setType(ContactsContract.Contacts.CONTENT_TYPE);
                contactIntent.putExtra("ITEM_POSITION", position);
                ((Activity) context).startActivityForResult(contactIntent, CONTACT_CHOOSER_ACTIVITY_CODE );

而且效果很好。但问题是：

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch (requestCode) {
....
...
...
}
}

我收到此错误：Cannot resolve method 'onActivityResult(int, int, android.content.Intent)' 有什么办法可以避免这种情况吗？或者是否可以在适配器 class 中使用此方法？如果不是我该怎么办？

Answer 1

您不能在任何适配器 class 中使用此方法，这只是 Activity 中的一个方法，每个 class extends Activity 都可以覆盖此方法，但是当然不是适配器。

请参阅java

中的Overrides

关于 onActivityResult，请参阅 Activity#onActivityResult(int, int, Intent)

对于 RecyclerView.Adapter 之类的东西，您需要在适配器中定义一个接口并在 Activity 中实现该接口。

例如，这里是一个应用程序的代码，它将所点击项目的字符串及其位置发送到显示它的新 Activity：

主要Activity:

public class MainActivity extends AppCompatActivity implements MyAdapter.CallbackInterface {


    private static final int MY_REQUEST = 1001;

    private static final String [] ITEMS = {"Item 1", "Item 2", "Item 3" ,"Item 4", "Item 5", "Item 6"};

    private MyAdapter myAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // ... Adapter setup, simple LinearLayoutManager and String [] used
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.rec_view);
        myAdapter = new MyAdapter(this, ITEMS);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(myAdapter);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch(resultCode){

            case RESULT_OK:

                // ... Check for some data from the intent
                if(requestCode == MY_REQUEST){
                    // .. lets toast again
                    int position = -1;
                    if(data != null){
                        position = data.getIntExtra("Position", 0);
                    }

                    if(position != -1) {
                        Toast.makeText(this, "Handled the result successfully at position " + position, Toast.LENGTH_SHORT).show();
                    }else{
                        Toast.makeText(this, "Failed to get data from intent" , Toast.LENGTH_SHORT).show();
                    }
                }

                break;

            case RESULT_CANCELED:

                // ... Handle this situation
                break;
        }
    }

    /**
     * Interface Method which communicates to the Acitivty here from the {@link MyAdapter}
     * @param position - the position
     * @param text - the text to pass back
     */
    @Override
    public void onHandleSelection(int position, String text) {

        Toast.makeText(this, "Selected item in list "+ position + " with text "+ text, Toast.LENGTH_SHORT).show();

        // ... Start a new Activity here and pass the values
        Intent secondActivity = new Intent(MainActivity.this, DetailActivity.class);
        secondActivity.putExtra("Text",text);
        secondActivity.putExtra("Position", position);
        startActivityForResult(secondActivity, MY_REQUEST);
    }
}

xml 主Activity:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.divshark.recyclerviewsimpledemo.MainActivity">

    <android.support.v7.widget.RecyclerView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/rec_view" />
</RelativeLayout>

我的适配器：

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyHolder>{

    private CallbackInterface mCallback;
    private String [] mMyItems;
    private Context mContext;

    public interface CallbackInterface{

        /**
         * Callback invoked when clicked
         * @param position - the position
         * @param text - the text to pass back
         */
        void onHandleSelection(int position, String text);
    }

    public MyAdapter(Context context, String [] myItems){

        mContext = context;
        mMyItems = myItems;

        // .. Attach the interface
        try{
            mCallback = (CallbackInterface) context;
        }catch(ClassCastException ex){
            //.. should log the error or throw and exception
            Log.e("MyAdapter","Must implement the CallbackInterface in the Activity", ex);
        }
    }

    @Override
    public int getItemCount() {
        return mMyItems.length;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public void onBindViewHolder(MyHolder holder, final int position) {

        // Set the text for the View
        holder.mTextView.setText(mMyItems[position]);

        // Use your listener to pass back the data
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(mCallback != null){
                    mCallback.onHandleSelection(position, mMyItems[position]);
                }
            }
        });
    }

    @Override
    public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(mContext).inflate(R.layout.list_item, parent, false);
        return new MyHolder(view);
    }

    static class MyHolder extends RecyclerView.ViewHolder{

        TextView mTextView;

        public MyHolder(View itemView) {
            super(itemView);

            mTextView = (TextView) itemView.findViewById(R.id.tv_list_item);
        }
    }
}

适配器布局：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="?listPreferredItemHeight">

    <TextView
        android:id="@+id/tv_list_item"
        android:textColor="@android:color/black"
        tools:text="Some Text Holder"
        android:layout_marginLeft="16dp"
        android:textSize="18sp"
        android:layout_centerVertical="true"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</RelativeLayout>

和细节Activity：

public class DetailActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.detail_activity);

        TextView textView = (TextView) findViewById(R.id.tv_detail_text);

        if(getIntent() != null && getIntent().getExtras() != null) {
            Bundle extras = getIntent().getExtras();
            String text = extras.getString("Text");
            int position = extras.getInt("Position");

            textView.setText(String.format("%s at position %d", text, position));

            // .. For this purpose set result okay and use position as part of data when Activity finishes
            // Which will in turn invoke the onActivityResult method in the calling activity
            Intent resultIntent = new Intent();
            resultIntent.putExtra("Position", position);
            setResult(RESULT_OK, resultIntent);
        }
    }
}

细节布局activity：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent">


    <TextView
        android:id="@+id/tv_detail_text"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</FrameLayout>

祝你好运，编码愉快！

Answer 2

另一种解决方案是在 activity class 中设置 onActivityResult 方法，您可以在其中启动 RecyclerView/ListView。这也有效，除了出于某种原因，当我尝试使用意图传递数据时出现 NPE 错误，因此解决方法是创建静态 String/Int 并更改它在点击和访问时的值。那很好用。但是上面的答案也很好，而且在性能方面也一样好，甚至更好。

Answer 3

我不知道你为什么需要从适配器调用 onActivityResult() 方法 class。

无论如何，最好的解决方案是从 adpater class 启动 ActivityForResult() 并通过指定请求代码和结果代码

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