第三篇 深入ListView篇

直奔主题~!

结构如图：

main.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
</LinearLayout>

showcontent.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical" android:layout_width="fill_parent"
	android:layout_height="fill_parent">
	<LinearLayout android:layout_width="fill_parent"
		android:layout_height="wrap_content" android:id="@+id/linearLayout1"
		android:gravity="center">
		<ImageView android:layout_width="100dip"
			android:layout_height="100dip" android:src="@drawable/icon"
			android:id="@+id/iv"></ImageView>
		<TextView android:text="今晚打老虎" android:id="@+id/tv"
			android:layout_width="wrap_content" android:layout_height="wrap_content"
			></TextView>
	</LinearLayout>

</LinearLayout>

Control_ListView_LoadingActivity.java代码:

public class Control_ListView_LoadingActivity extends ListActivity implements
		OnScrollListener {
	private LayoutParams layoutParams1 = new LinearLayout.LayoutParams(
			LinearLayout.LayoutParams.WRAP_CONTENT,
			LinearLayout.LayoutParams.WRAP_CONTENT);
	private LayoutParams layoutParams2 = new LinearLayout.LayoutParams(
			LinearLayout.LayoutParams.FILL_PARENT,
			LinearLayout.LayoutParams.FILL_PARENT);
	private ProgressBar pb;
	private TextView tv;
	private int lastItem = 0;
	mylistener adapter;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		// setContentView(R.layout.main);
		Layout_initialize();
	}

	public void Layout_initialize() {
		LinearLayout ll1 = new LinearLayout(
				Control_ListView_LoadingActivity.this);
		pb = new ProgressBar(Control_ListView_LoadingActivity.this);
		tv = new TextView(Control_ListView_LoadingActivity.this);
		pb.setPadding(0, 0, 15, 0);
		ll1.addView(pb, layoutParams1);
		tv.setText("正在加载...");
		tv.setGravity(Gravity.CENTER_HORIZONTAL);
		ll1.addView(tv, layoutParams2);
		ll1.setGravity(Gravity.CENTER);
		LinearLayout loadingLayout = new LinearLayout(this);
		loadingLayout.addView(ll1, layoutParams1);
		loadingLayout.setGravity(Gravity.CENTER);
		ListView listView = getListView();
		listView.addFooterView(loadingLayout);
		registerForContextMenu(listView);
		adapter = new mylistener(Control_ListView_LoadingActivity.this);
		setListAdapter(adapter);
		listView.setOnScrollListener(Control_ListView_LoadingActivity.this);

	}

	Handler hd = new Handler() {

		@Override
		public void handleMessage(Message msg) {
			// TODO Auto-generated method stub
			// super.handleMessage(msg);
			if (msg.what == 123) {

				adapter.notifyDataSetChanged();
				// setListAdapter(adapter);
			}
		}

	};

	public void onScroll(AbsListView view, int firstVisibleItem,
			int visibleItemCount, int totalItemCount) {
		// TODO Auto-generated method stub
		lastItem = firstVisibleItem + visibleItemCount - 1;

	}

	public void onScrollStateChanged(AbsListView view, int scrollState) {
		// TODO Auto-generated method stub
		
	      
		// 这里并没有执行 ,所以可以放到onscroll里进行解决,原因暂定
        if(scrollState==OnScrollListener.SCROLL_STATE_IDLE)
        {
        	Toast.makeText(Control_ListView_LoadingActivity.this, "没有调用", Toast.LENGTH_LONG).show();
        }
	
		if (lastItem == adapter.count) {
			adapter.count += 5;
			Message msg = hd.obtainMessage(123);
			hd.sendMessage(msg);

		}
	}

	class mylistener extends BaseAdapter {
		Context ct;
		int count = 5;

		public mylistener(Context ct) {
			this.ct = ct;
		}

		public int getCount() {
			// TODO Auto-generated method stub
			return count;
		}

		public Object getItem(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			// return null;
			LayoutInflater lif = getLayoutInflater();
			convertView = lif.inflate(R.layout.showcontent, null);
			return convertView;
		}

	}
}