Java 无法通过活动更新listview

我创建了一个基于

listview

的应用程序，当我通过另一个活动添加数据时，数据不会在

listview

中更新，因为它应该在listview中更新

当我在“活动”中的“保存”按钮上创建了一个

onSave

方法，但它似乎没有在列表视图中得到更新时

mainactivity.java

package com.example.listviewdemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.ListView;

public class MainActivity extends Activity {
    TimeTrackerAdapter timeTrackerAdapter;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView)
                findViewById(R.id.times_list);
                timeTrackerAdapter = new TimeTrackerAdapter();
                listView.setAdapter(timeTrackerAdapter);
    }

    public boolean onCreateOptionsMenu(Menu m) {
        super.onCreateOptionsMenu(m);
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.time_list_menu, m );
        return true;
    }

    public static final int TIME_ENTRY_REQUEST_CODE = 1;
    public boolean onMenuItemSelected(int featureId, MenuItem item) {
        if (item.getItemId() == R.id.add_time_menu_item) {
            Intent intent = new Intent(this, AddTimeActivity.class);
            startActivityForResult(intent, TIME_ENTRY_REQUEST_CODE);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == TIME_ENTRY_REQUEST_CODE) {
            if (resultCode == RESULT_OK) {
                String notes = data.getStringExtra("notes");
                String time = data.getStringExtra("time");

                timeTrackerAdapter.addTimeRecord( new TimeRecord(time, notes));
                timeTrackerAdapter.notifyDataSetChanged();
            }
            }
    }



}

package com.example.listviewdemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class AddTimeActivity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_time);
        }
    public void onCancel(View view) {
        finish();
    }
    public void onSave(View view) {
        Intent intent = getIntent();

        EditText timeView = (EditText)findViewById(R.id.time_view);
        intent.putExtra("time", timeView.getText().toString());

        EditText notesView = (EditText)findViewById(R.id.notes_view);
        intent.putExtra("notes", notesView.getText().toString());

        this.setResult(RESULT_OK, intent);
        finish();
    }
}

    package com.example.listviewdemo;

import java.util.ArrayList;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class TimeTrackerAdapter extends BaseAdapter {
    private ArrayList<TimeRecord> times = new ArrayList<TimeRecord>();
    public TimeTrackerAdapter() {
        times.add(new TimeRecord(
                "38:23", "Feeling good!"));
                times.add(new TimeRecord(
                "49:01", "Tired. Needed more caffeine"));
                times.add(new TimeRecord(
                "26:21", "I’m rocking it!"));
                times.add(new TimeRecord(
                "29:42", "Lost some time on the hills, but pretty good."));     
    }

    @Override
    public int getCount() {
        return times.size();
    }

    @Override
    public Object getItem(int index) {
        return getItem(index);
    }

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

    @Override
    public View getView(int index, View view, ViewGroup parent) {
        if (view == null) {
            LayoutInflater inflater =
                    LayoutInflater.from(parent.getContext());
            view = inflater.inflate(
                    R.layout.time_list_item, parent, false);
        }
        TimeRecord time = times.get(index);
        TextView timeTextView = (TextView)
                view.findViewById(R.id.time_view);
        timeTextView.setText(time.getTime());
        TextView notesTextView = (TextView)
                view.findViewById(R.id.notes_view);
        notesTextView.setText(time.getNotes());
        return view;

    }

    public void addTimeRecord(TimeRecord timeRecord) {
        // TODO Auto-generated method stub

    }





}

addtimeactivity.java

package com.example.listviewdemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.ListView;

public class MainActivity extends Activity {
    TimeTrackerAdapter timeTrackerAdapter;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView)
                findViewById(R.id.times_list);
                timeTrackerAdapter = new TimeTrackerAdapter();
                listView.setAdapter(timeTrackerAdapter);
    }

    public boolean onCreateOptionsMenu(Menu m) {
        super.onCreateOptionsMenu(m);
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.time_list_menu, m );
        return true;
    }

    public static final int TIME_ENTRY_REQUEST_CODE = 1;
    public boolean onMenuItemSelected(int featureId, MenuItem item) {
        if (item.getItemId() == R.id.add_time_menu_item) {
            Intent intent = new Intent(this, AddTimeActivity.class);
            startActivityForResult(intent, TIME_ENTRY_REQUEST_CODE);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == TIME_ENTRY_REQUEST_CODE) {
            if (resultCode == RESULT_OK) {
                String notes = data.getStringExtra("notes");
                String time = data.getStringExtra("time");

                timeTrackerAdapter.addTimeRecord( new TimeRecord(time, notes));
                timeTrackerAdapter.notifyDataSetChanged();
            }
            }
    }



}

package com.example.listviewdemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class AddTimeActivity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_time);
        }
    public void onCancel(View view) {
        finish();
    }
    public void onSave(View view) {
        Intent intent = getIntent();

        EditText timeView = (EditText)findViewById(R.id.time_view);
        intent.putExtra("time", timeView.getText().toString());

        EditText notesView = (EditText)findViewById(R.id.notes_view);
        intent.putExtra("notes", notesView.getText().toString());

        this.setResult(RESULT_OK, intent);
        finish();
    }
}

    package com.example.listviewdemo;

import java.util.ArrayList;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class TimeTrackerAdapter extends BaseAdapter {
    private ArrayList<TimeRecord> times = new ArrayList<TimeRecord>();
    public TimeTrackerAdapter() {
        times.add(new TimeRecord(
                "38:23", "Feeling good!"));
                times.add(new TimeRecord(
                "49:01", "Tired. Needed more caffeine"));
                times.add(new TimeRecord(
                "26:21", "I’m rocking it!"));
                times.add(new TimeRecord(
                "29:42", "Lost some time on the hills, but pretty good."));     
    }

    @Override
    public int getCount() {
        return times.size();
    }

    @Override
    public Object getItem(int index) {
        return getItem(index);
    }

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

    @Override
    public View getView(int index, View view, ViewGroup parent) {
        if (view == null) {
            LayoutInflater inflater =
                    LayoutInflater.from(parent.getContext());
            view = inflater.inflate(
                    R.layout.time_list_item, parent, false);
        }
        TimeRecord time = times.get(index);
        TextView timeTextView = (TextView)
                view.findViewById(R.id.time_view);
        timeTextView.setText(time.getTime());
        TextView notesTextView = (TextView)
                view.findViewById(R.id.notes_view);
        notesTextView.setText(time.getNotes());
        return view;

    }

    public void addTimeRecord(TimeRecord timeRecord) {
        // TODO Auto-generated method stub

    }





}

timetrackeradapter.java

package com.example.listviewdemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.ListView;

public class MainActivity extends Activity {
    TimeTrackerAdapter timeTrackerAdapter;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = (ListView)
                findViewById(R.id.times_list);
                timeTrackerAdapter = new TimeTrackerAdapter();
                listView.setAdapter(timeTrackerAdapter);
    }

    public boolean onCreateOptionsMenu(Menu m) {
        super.onCreateOptionsMenu(m);
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.time_list_menu, m );
        return true;
    }

    public static final int TIME_ENTRY_REQUEST_CODE = 1;
    public boolean onMenuItemSelected(int featureId, MenuItem item) {
        if (item.getItemId() == R.id.add_time_menu_item) {
            Intent intent = new Intent(this, AddTimeActivity.class);
            startActivityForResult(intent, TIME_ENTRY_REQUEST_CODE);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == TIME_ENTRY_REQUEST_CODE) {
            if (resultCode == RESULT_OK) {
                String notes = data.getStringExtra("notes");
                String time = data.getStringExtra("time");

                timeTrackerAdapter.addTimeRecord( new TimeRecord(time, notes));
                timeTrackerAdapter.notifyDataSetChanged();
            }
            }
    }



}

package com.example.listviewdemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class AddTimeActivity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_time);
        }
    public void onCancel(View view) {
        finish();
    }
    public void onSave(View view) {
        Intent intent = getIntent();

        EditText timeView = (EditText)findViewById(R.id.time_view);
        intent.putExtra("time", timeView.getText().toString());

        EditText notesView = (EditText)findViewById(R.id.notes_view);
        intent.putExtra("notes", notesView.getText().toString());

        this.setResult(RESULT_OK, intent);
        finish();
    }
}

    package com.example.listviewdemo;

import java.util.ArrayList;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class TimeTrackerAdapter extends BaseAdapter {
    private ArrayList<TimeRecord> times = new ArrayList<TimeRecord>();
    public TimeTrackerAdapter() {
        times.add(new TimeRecord(
                "38:23", "Feeling good!"));
                times.add(new TimeRecord(
                "49:01", "Tired. Needed more caffeine"));
                times.add(new TimeRecord(
                "26:21", "I’m rocking it!"));
                times.add(new TimeRecord(
                "29:42", "Lost some time on the hills, but pretty good."));     
    }

    @Override
    public int getCount() {
        return times.size();
    }

    @Override
    public Object getItem(int index) {
        return getItem(index);
    }

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

    @Override
    public View getView(int index, View view, ViewGroup parent) {
        if (view == null) {
            LayoutInflater inflater =
                    LayoutInflater.from(parent.getContext());
            view = inflater.inflate(
                    R.layout.time_list_item, parent, false);
        }
        TimeRecord time = times.get(index);
        TextView timeTextView = (TextView)
                view.findViewById(R.id.time_view);
        timeTextView.setText(time.getTime());
        TextView notesTextView = (TextView)
                view.findViewById(R.id.notes_view);
        notesTextView.setText(time.getNotes());
        return view;

    }

    public void addTimeRecord(TimeRecord timeRecord) {
        // TODO Auto-generated method stub

    }





}

package com.example.listviewdemo；
导入java.util.ArrayList；
导入android.view.LayoutInflater；
导入android.view.view；
导入android.view.ViewGroup；
导入android.widget.BaseAdapter；
导入android.widget.TextView；
公共类TimeTrackerAdapter扩展BaseAdapter{
private ArrayList times=new ArrayList（）；
公共时间跟踪器适配器（）{
添加（新的时间记录）(
“38:23”，“感觉很好！”；
添加（新的时间记录）(
“49:01”，“累了，需要更多的咖啡因”）；
添加（新的时间记录）(
“26:21”，“我在摇它！”；
添加（新的时间记录）(
“29:42”，“在山上耽误了一些时间，但还不错。”）；
}
@凌驾
public int getCount（）{
返回次数。size（）；
}
@凌驾
公共对象getItem（int索引）{
返回项目（索引）；
}
@凌驾
公共长getItemId（int索引）{
收益指数；
}
@凌驾
公共视图getView（int索引、视图视图、视图组父级）{
如果（视图==null）{
充气机=
LayoutInflater.from（parent.getContext（））；
视图=充气机。充气(
R.layout.time\u list\u项，父项，false）；
}
TimeRecord time=times.get（索引）；
TextView timeTextView=（TextView）
view.findViewById（R.id.time\u视图）；
timeTextView.setText（time.getTime（））；
TextView notesTextView=（TextView）
视图。findViewById（R.id.notes\u视图）；
notesTextView.setText（time.getNotes（））；
返回视图；
}
public void addTimeRecord（TimeRecord TimeRecord）{
//TODO自动生成的方法存根
}
}

您的问题是这一行：

public void addTimeRecord(TimeRecord timeRecord) {
    // TODO Auto-generated method stub

}

你还没有真正实现这个函数，所以它不会做任何事情！我猜你想这样做：

public void addTimeRecord(TimeRecord timeRecord) {
    times.add(timeRecord);
    notifyDataSetChanged();
}

---

请注意，这样一来，在第一个活动中就不需要冗余的

notifyDataSetChanged（）

。

为什么

addTimeRecord

是空的

试试这个

public void addTimeRecord(TimeRecord timeRecord) {
    times.add(timeRecord);
}

---

开始倒转。有人打电话给你吗？你是在你的if声明里说的吗？继续这样做，直到找到问题。我没有得到问题，我甚至尝试在断点的帮助下进行调试，但是@PearSonartPhoto没有任何用处您从什么角度确认了事情似乎在运行？事情一直在运行，除了数据没有添加到列表视图中，因为它应该是这样的。您确实需要包含

TimeTrackerAdapter

的代码，因为您拥有的一切似乎都在正常运行，但是我不确定什么是

TimeTrackerAdapter

，更不用说它是否做了正确的事情了。呃，这就解决了，当创建onActivityResult AddTimeRecord时产生了错误，为此我生成了自动生成的方法来抑制错误。谢谢你是的，因为我说它变成了一个自动生成的方法，所以我没有太多的关注它，我的无知。它与时间一起工作。添加（时间记录）；非常感谢。