Android 使用适配器显示SQLiteDatabase中的数据

DBHelper类的代码：

人族活动的代码：

public class Terran extends Activity {

    private DBHelper dbHelp = null;
    private Cursor ourCursor = null;
    private DBAdapter adapter = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        try {

            super.onCreate(savedInstanceState);
            setContentView(R.layout.terran_layout);

            // this is our listview element, obtained by id from our xml layout
            ListView myListView = (ListView) findViewById(R.id.tvterran);

            // create our database helper
            dbHelp = new DBHelper(this);
            // we call the create right afther initializing helper
            dbHelp.createDatabase();
            // open the database
            dbHelp.openDataBase();
            // get our cursor
            ourCursor = dbHelp.getTerran();

            // tell android to start managing cursor
            startManagingCursor(ourCursor);
            // create our adapter
            adapter = new DBAdapter(ourCursor);
            // set the adapter
            myListView.setAdapter(adapter);

        } catch (Exception e) {

            // send real error message
            Log.e("ERROR", "ERROR IN CODE: " + e.toString());

            e.printStackTrace();
        }
    }

    class DBAdapter extends CursorAdapter {
        DBAdapter(Cursor c) {
            super(Terran.this, c);
        }

        @Override
        public void bindView(View row, Context ctxt, Cursor c) {
            // TODO Auto-generated method stub
            terranHolder holder = (terranHolder) row.getTag();
            holder.populateFrom(c, dbHelp);

        }

        @Override
        public View newView(Context ctxt, Cursor c, ViewGroup parent) {
            // TODO Auto-generated method stub
            LayoutInflater inflater = getLayoutInflater();
            View row = inflater.inflate(R.layout.terran_layout, parent, false);
            terranHolder holder = new terranHolder(row);
            row.setTag(holder);
            return (row);
        }
    }

    static class terranHolder {
        private TextView name = null;

        terranHolder(View row) {
            name = (TextView) row.findViewById(R.id.tvterran);
        }

        void populateFrom(Cursor c, DBHelper r) {
            name.setText(r.getName(c));
        }
    }

}

Logcat异常：

01-30 20:07:13.765: E/ERROR(7153): ERROR IN CODE: java.lang.NullPointerException
01-30 20:07:13.775: W/System.err(7153): java.lang.NullPointerException
01-30 20:07:13.775: W/System.err(7153):     at com.subdeveloper.starcraftbuilds.Terran.onCreate(Terran.java:46)
01-30 20:07:13.775: W/System.err(7153):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-30 20:07:13.775: W/System.err(7153):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
01-30 20:07:13.775: W/System.err(7153):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1499)
01-30 20:07:13.775: W/System.err(7153):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127)
01-30 20:07:13.775: W/System.err(7153):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339)
01-30 20:07:13.775: W/System.err(7153):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:731)
01-30 20:07:13.775: W/System.err(7153):     at android.widget.TabHost.setCurrentTab(TabHost.java:403)
01-30 20:07:13.775: W/System.err(7153):     at android.widget.TabHost.addTab(TabHost.java:242)

---

我无法从查询结果中获取要生成的ListView。从我的调试中，我了解到错误在第46行的人族类中。我想不出是怎么回事。通过与其他数据库的测试，数据库连接可以正常工作

com.subdeveloper.starcraftbuilds.Terran.onCreateTerran.java:46

在中放置断点并运行调试器。有些东西是空的，我猜是列表。它开得像46

顺便说一句，我是黄金随机球员。过去是高抛钻石。祝项目顺利

您的ListView为空，这意味着您的布局中没有具有该id的ListView，或者android没有为列表生成正确的id，并且您的旧id不正确

---

尝试刷新项目，从gen文件夹中删除R类，以便再次生成ID，重新启动IDE。

除了您向我们展示的内容外，还可以指出哪一行是第46行。myListView.setAdapteradapter；第46行可能是ListView未正确初始化。你确定在你的R.layout.terran\u布局中有一个id为tvterran的列表视图吗？是的，带有名为tvterran的列表视图的linearlayout。添加一个日志。检查这个，lisview:+myListView就在第46行之前，然后运行你的应用程序。在Logcat中查看这一行返回的内容。tryed debugation显示适配器有值，直到初始化listview。逐步完成它。在那里的某个地方是空的。

01-30 20:07:13.765: E/ERROR(7153): ERROR IN CODE: java.lang.NullPointerException
01-30 20:07:13.775: W/System.err(7153): java.lang.NullPointerException
01-30 20:07:13.775: W/System.err(7153):     at com.subdeveloper.starcraftbuilds.Terran.onCreate(Terran.java:46)
01-30 20:07:13.775: W/System.err(7153):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-30 20:07:13.775: W/System.err(7153):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
01-30 20:07:13.775: W/System.err(7153):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1499)
01-30 20:07:13.775: W/System.err(7153):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127)
01-30 20:07:13.775: W/System.err(7153):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339)
01-30 20:07:13.775: W/System.err(7153):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:731)
01-30 20:07:13.775: W/System.err(7153):     at android.widget.TabHost.setCurrentTab(TabHost.java:403)
01-30 20:07:13.775: W/System.err(7153):     at android.widget.TabHost.addTab(TabHost.java:242)