一個添加刪除黑名單的小記錄（11）

public class MainActivity extends Activity {
	private ListView listview;
	private EditText info_phonenumber;// 輸入號碼
	private TextView empty;
	private ArrayAdapter<String> adapter;
	private Map<String, Object> mapUser;// 存放號碼的map

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		listview = (ListView) this.findViewById(R.id.listview);
		info_phonenumber = (EditText) this.findViewById(R.id.info_text);
		empty = (TextView) this.findViewById(R.id.empty);
		// 給listview註冊上下文
		listview.setEmptyView(empty);// 這一步設置當沒有數據時才顯示這個empty控件
		mapUser = new HashMap<String, Object>();
		List<String> list = getBlacklist();
		adapter = new ArrayAdapter<String>(this,
				android.R.layout.simple_list_item_1, list);
		listview.setAdapter(adapter);
		registerForContextMenu(listview);//給上下文菜單註冊

	}

	@Override//上下文菜單
	public void onCreateContextMenu(ContextMenu menu, View v,
			ContextMenuInfo menuInfo) {
		AdapterContextMenuInfo contextMenuInfo = (AdapterContextMenuInfo) menuInfo;
		menu.setHeaderIcon(R.drawable.ic_launcher);
		// 裝換成：AdapterContextMenuInfo後獲取選取的那一項的位置（position）

		menu.setHeaderTitle("提示："
				+ getBlacklist().get(contextMenuInfo.position));
		getMenuInflater().inflate(R.menu.menu, menu);
		super.onCreateContextMenu(menu, v, menuInfo);
	}

	@Override
	public boolean onContextItemSelected(MenuItem item) {
		AdapterContextMenuInfo contextMenuInfo = (AdapterContextMenuInfo) item
				.getMenuInfo();
		// 拿到該位置的內容，即號碼
		String key = getBlacklist().get(contextMenuInfo.position);
		switch (item.getItemId()) {
		case R.id.delete:
			mapUser.remove(key);
			fillListView();
			break;
		case R.id.noaction:
			break;
		}
		return super.onContextItemSelected(item);
	}

	// 按鈕事件
	public void checkButton(View view) {
		switch (view.getId()) {
		case R.id.bnt_add:
			String phonenumber = info_phonenumber.getText().toString();
			// 將號碼添加到map中
			mapUser.put(phonenumber, null);
			fillListView();
			break;
		case R.id.bnt_clear:
			mapUser.clear();
			fillListView();
			break;
		}
	}

	// 更新數據
	public void fillListView() {
		adapter.clear();
		adapter.addAll(getBlacklist());
	}

	private List<String> getBlacklist() {
		List<String> list = new ArrayList<String>();
		for (Map.Entry<String, Object> entry : mapUser.entrySet()) {
			list.add(entry.getKey());// 將號碼放到集合中
		}
		return list;

	}
}

//佈局
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <EditText
        android:id="@+id/info_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="請輸入黑名單號碼" />

    <LinearLayout
        android:id="@+id/layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/info_text"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/bnt_add"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="checkButton"
            android:text="添加黑名單" />

        <Button
            android:id="@+id/bnt_clear"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="checkButton"
            android:text="刪除黑名單" />
    </LinearLayout>

    <TextView
        android:id="@+id/show_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/layout"
        android:text="如下是添加的數據" />

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/show_text" />

    <TextView
        android:id="@+id/empty"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/listview"
        android:text="沒有更多內容" />

</RelativeLayout>