【Android】错误Cyclic inheritance in

作者: itbird01 | 来源:发表于2018-08-03 12:00 被阅读10次
    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<String> data = new ArrayList<String>();
            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<String> data = new ArrayList<String>();
            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<String> mList;
        private LayoutInflater mInflater;
        private ListViewButtonClickListener mListener;
    
        public ListViewAdapter(Context context, ArrayList<String> 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;
        }
    }
    
    

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