Question

我想在Android编程上编写自定义ListView代码这是我的RowObject类：

public class RowObject {
    public int icon;
    public String title;

    public RowObject() {
        super();
    }

    public RowObject(int icon, String title) {
        super();
        this.icon = icon;
        this.title = title;
    }
}

My RowAdapter类：

public class RowAdapter extends ArrayAdapter<RowObject> {
    Context _context;
    int _layoutResourceId;
    RowObject[] _arrayData;

    public RowAdapter(Context context, int layoutResourceId,
            RowObject[] arrayData) {
        super(context, layoutResourceId, arrayData);
        this._context = context;
        this._layoutResourceId = layoutResourceId;
        this._arrayData = arrayData;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        View _row = convertView;
        RowObjectViewHolder _viewHolder = null;

        if (_row == null) {
            LayoutInflater _inflater = ((Activity) _context)
                    .getLayoutInflater();
            _row = _inflater.inflate(_layoutResourceId, parent, false);

            _viewHolder = new RowObjectViewHolder();
        //  _viewHolder._imgIcon = (ImageView) _row.findViewById(R.id.imgIcon);
            _viewHolder._txtTitle = (TextView) _row.findViewById(R.id.txtTitle);
            _viewHolder._cbxCheck = (CheckBox) _row.findViewById(R.id.cbxCheck);
            _row.setTag(_viewHolder);
        } else {
            _viewHolder = (RowObjectViewHolder) _row.getTag();
        }
        RowObject _objRow = _arrayData[position];
        _viewHolder._txtTitle.setText(_objRow.title);
    //  _viewHolder._imgIcon.setImageResource(_objRow.icon);
        _viewHolder._cbxCheck.setChecked(false);
        return _row;
    }

    static class RowObjectViewHolder {
        //ImageView _imgIcon;
        TextView _txtTitle;
        CheckBox _cbxCheck;
    }
}

在MainActivity类中，我调用RowAdaper类。没关系，我有一个自定义的ListView：

public class MainActivity extends Activity {
    // Alt + Shift + S: override method
    private ListView _listView;

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

        RowObject _arrayRowObject[] = new RowObject[] {
                new RowObject(R.drawable.facebook, "Facebook"),
                new RowObject(R.drawable.skype, "Skype") };

        RowAdapter adapter = new RowAdapter(this, R.layout.listview_item_row,
                _arrayRowObject);

        _listView = (ListView) findViewById(R.id.listView);
        View header = (View) getLayoutInflater().inflate(
                R.layout.listview_header_row, null);
        _listView.addHeaderView(header);

        _listView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

但是，当我创建一个新的Activity（Main1Activity）时，我希望在第一次运行时调用Main1Activity。
在MainActivity类中，我有：

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main1);
        }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

因为第一次调用setContentView(R.layout.activity_main1); Main1Activity 但是，当我插入一些代码（调用适配器）时，我没有看到ListView。什么问题？

public class Main1Activity extends Activity {
    private ListView _listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main1);

        RowObject _arrayRowObject[] = new RowObject[] {
                new RowObject(R.drawable.facebook, "Facebook"),
                new RowObject(R.drawable.skype, "Skype") };

        RowAdapter adapter = new RowAdapter(this.getBaseContext(), R.layout.listview_item_row,
                _arrayRowObject);

        _listView = (ListView) findViewById(R.id.listView);
        View header = (View) getLayoutInflater().inflate(
                R.layout.listview_header_row, null);
        _listView.addHeaderView(header);

        _listView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main1, menu);

        return true;
    }

}

我想我在这一行有问题：

RowAdapter adapter = new RowAdapter(this.getBaseContext(), R.layout.listview_item_row,
                    _arrayRowObject);

你可以帮我解决这个问题吗？谢谢！

Answer 1

如果您希望在启动应用时调用Main1Activity，那么仅更改setContentView中的布局是不够的。你需要在android manifest文件中指定你的启动器活动。

<intent-filter>
     <action android:name="android.intent.action.MAIN" />

     <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

您需要使用此意图过滤器。

例如：

在应用启动时启动MainActivity

<application
        android:allowBackup="true"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name=".Main1Activity"
            android:label="@string/app_name" >

        </activity>
    </application>

或者，如果您要启动Main1Activity

<application
        android:allowBackup="true"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >

        </activity>

        <activity
            android:name=".Main1Activity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

希望很清楚！

在Android编程中从另一个活动（不是主要活动）调用自定义ListView时出错？

1 个答案: