【Android】错误Cyclic inheritance involving(循环继承问题)

编译工程时，遇到“Cyclic inheritance involving”，翻译过来就是，

编译错误.png

实际代码：

package itbird.com.myapplication33;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;

/**
 * MainActivity
 * @author itbird
 */
public class MainActivity extends AppCompatActivity implements MainActivity.ListViewButtonClickListener {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView) findViewById(R.id.listview);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this, "listview item click position = " + position, Toast.LENGTH_SHORT).show();
            }
        });
        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this, "listview item long click position = " + position, Toast.LENGTH_SHORT).show();
                return true;
            }
        });
        ArrayList data = new ArrayList();
        data.add("test1");
        data.add("test2");
        data.add("test3");

        ListViewAdapter adapter = new ListViewAdapter(this, data);
        adapter.setOnButtonClickListener(this);
        listView.setAdapter(adapter);
    }

    public interface ListViewButtonClickListener {
        void onClick(int position);
    }

    @Override
    public void onClick(int position) {
        Toast.makeText(MainActivity.this, "listview item button long click position = " + position, Toast.LENGTH_SHORT).show();
    }
}

错误原因：

循坏继承在java中是不允许的，不仅仅局限于接口，类也不能循环继承。因为编译的时候，编译器不知道该先编译哪个。比如你的这个例子，编译class MainActivity的时候需要先编译MainActivity.ListViewButtonClickListener，但是MainActivity.ListViewButtonClickListener又是class MainActivity的内部接口

解决方法：

只要把接口ListViewButtonClickListener移动到另外的文件中就不会有这样的问题了

package itbird.com.myapplication33;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;

/**
 * MainActivity
 * @author itbird
 */
public class MainActivity extends AppCompatActivity implements ListViewAdapter.ListViewButtonClickListener {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView) findViewById(R.id.listview);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this, "listview item click position = " + position, Toast.LENGTH_SHORT).show();
            }
        });
        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this, "listview item long click position = " + position, Toast.LENGTH_SHORT).show();
                return true;
            }
        });
        ArrayList data = new ArrayList();
        data.add("test1");
        data.add("test2");
        data.add("test3");

        ListViewAdapter adapter = new ListViewAdapter(this, data);
        adapter.setOnButtonClickListener(this);
        listView.setAdapter(adapter);
    }

    @Override
    public void onClick(int position) {
        Toast.makeText(MainActivity.this, "listview item button long click position = " + position, Toast.LENGTH_SHORT).show();
    }
}

package itbird.com.myapplication33;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.TextView;

import java.util.ArrayList;

/**
 * ListViewAdapter
 * Created by itbird on 2018/8/3.
 */

public class ListViewAdapter extends BaseAdapter {
    private Context mContext;
    private ArrayList mList;
    private LayoutInflater mInflater;
    private ListViewButtonClickListener mListener;

    public ListViewAdapter(Context context, ArrayList stringList) {
        mContext = context;
        mList = stringList;
        mInflater = LayoutInflater.from(mContext);
    }

    public void setOnButtonClickListener(ListViewButtonClickListener listener) {
        mListener = listener;
    }

    @Override
    public int getCount() {
        if (mList == null) {
            return 0;
        }
        return mList.size();
    }

    @Override
    public Object getItem(int position) {
        if (mList == null) {
            return null;
        }
        return mList.get(position);
    }

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

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
        if (convertView == null) {
            // 下拉项布局
            convertView = mInflater.inflate(R.layout.list_item_btn, null);
            holder = new ViewHolder();
            holder.title = (TextView) convertView.findViewById(R.id.title);
            holder.btn = (Button) convertView.findViewById(R.id.btn);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.title.setText(mList.get(position));
        // 通常将position设置为tag，方便之后判断点击的button是哪一个
        holder.btn.setTag(position);
        holder.btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mListener != null) {
                    mListener.onClick(position);
                }
            }
        });
        return convertView;
    }

    public interface ListViewButtonClickListener {
        void onClick(int position);
    }

    class ViewHolder {
        TextView title;
        Button btn;
    }
}