举例说明ListView的用法

通过在Layout中添加ListView Widget可以达到在页面布局具有列表效果的交互页面。在这里通过举例来说明怎样在Layout中添加ListView以及怎样应用。

配合设计了两个事件Listener: OnItemSelectedListener事件为鼠标的滚轮转动时所选择的值；OnItemClickListener事件则为当鼠标单击时，所触发的事件。由此可以区别出list中的“选择”与“单击”差异。

使用ArrayAdapter(Context context, int textViewResourceId , T[] objects)这个构造器，其中textViewResourceId是定义在“res/layout/my_simple_list_item.xml”里的资源ResourceID(R.layout.my_simple_list_item),里面使用CheckedTextView来取得ListView中选择的项目。

程序中使用了LinearLayout对象，动态地将TextView与ListView附加进原有的Layout布局当中。用LinearLayout.LayoutParams来创建对象param1,再调用LinearLayout的addView方法将TextView和ListView以及params对象传入。

程序如下所示：

public class A07Activity extends Activity {

private static final String[]week="sunday","monday","tuesday","wednesday","thursday","friday","saturday"};

private TextView tv;

private ListView lv;

private ArrayAdapter<String> aa;

private LinearLayout ll;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

tv=new TextView(this);

tv.setText(R.string.title);

tv.setTextColor(Color.RED);

lv=new ListView(this);

lv.setBackgroundColor(Color.GREEN);

ll=new LinearLayout(this);

ll.setOrientation(LinearLayout.VERTICAL);

ll.setBackgroundColor(android.graphics.Color.YELLOW);

aa=new ArrayAdapter<String>(A07Activity.this,R.layout.my_simple_list,week);

lv.setAdapter(aa);

LinearLayout.LayoutParams params01=new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);

ll.addView(lv, params01);

LinearLayout.LayoutParams params02=new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);

ll.addView(tv, params02);

setContentView(ll);

lv.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView<?> arg0, View arg1,

int arg2, long arg3) {

// TODO Auto-generated method stub

tv.setText("你选择的是："+arg0.getSelectedItem().toString());

}

@Override

public void onNothingSelected(AdapterView<?> arg0) {

// TODO Auto-generated method stub

}

});

lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {

@Override

public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,

long arg3) {

// TODO Auto-generated method stub

tv.setText("你选择的是："+week[arg2]);

}

});

}

}

res/layout/my_simple_list.xml如下:

<?xml version="1.0" encoding="utf-8"?>

<CheckedTextView

xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/myCheckedTextView1"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

/>