用户界面（四）GridView、ScrollView

1. GridView

1) gridview.xml 

<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:id="@+id/gridview"
    android:numColumns="auto_fit"
    android:verticalSpacing="10dp"
    android:horizontalSpacing="10dp"
    android:columnWidth="90dp"
    android:stretchMode="columnWidth"
    android:gravity="center" 
     ></GridView>
           

2) GridActivity.java

public class GridActivity extends Activity{
	private GridView m_gridview=null;
	private SimpleAdapter mSimpleAdapter;
	private List<Map<String, Integer>> mList = new ArrayList<Map<String, Integer>>();
	public  void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.gridview);
	    
		m_gridview=(GridView)findViewById(R.id.gridview);
		m_gridview.setBackgroundResource(R.drawable.mm);
		//设置Adapter
		initSimpleAdapter();
		m_gridview.setAdapter(mSimpleAdapter);
		m_gridview.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// TODO Auto-generated method stub
				if(position==0)
				{
					Intent m_Inten1=new Intent(GridActivity.this,GalleryActivity.class);
					startActivity(m_Inten1);
				}
			}			
		});	
	}	
	private void initSimpleAdapter() {
		Field[] fields = R.drawable.class.getDeclaredFields(); // 取得drawable下的全部属性
		// 循环取得的属性，以pic开头的都是要显示的图片，保存到list里面
		for (Field field : fields) {
			if (field.getName().startsWith("pic")) {
				Map<String, Integer> map = new HashMap<String, Integer>();
				try {
					map.put("image", field.getInt(R.drawable.class));
				} catch (Exception e) {
					e.printStackTrace();
				}
				mList.add(map);
			}
		}
		mSimpleAdapter = new SimpleAdapter(this, mList, R.layout.gallery_item,
				new String[] { "image" }, new int[] { R.id.image });				
	}	
}
           

实现的效果就和手机上的界面一个，一个个应用图标排列在主界面上。

2. SCrollView

  ScrollView的作用是当一屏显示不完时，可以通过滚动来显示。

1）scroll.xml

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/scroll"
    android:scrollbars="none">
    <LinearLayout 
        android:id="@+id/layout"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
        <TextView 
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="textview"
            android:id="@+id/textview1"  
           />
        <Button 
            android:id="@+id/button1"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"         
         />     
    </LinearLayout>
</ScrollView>
           

ScrollView 中包含一个线性布局，这个线性布局中由一个TextView和一个Button组成，因此点击按钮时每次也增加一个这样的线性布局。

2）ScrollActivity.java

public class ScrollActivity extends Activity{
	private LinearLayout m_Layout;
	private ScrollView m_ScrollView;
	private final Handler m_Handler=new Handler();
	
	public void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.scrollview);
		
		m_Layout=(LinearLayout)findViewById(R.id.layout);
		m_ScrollView=(ScrollView)findViewById(R.id.scroll);
		Button m_Button=(Button)findViewById(R.id.button1);
		m_Button.setOnClickListener(new Button.OnClickListener(){
			private int mIndex=1;
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				TextView textView=new TextView(ScrollActivity.this);
				textView.setText("Text view"+mIndex);
				LinearLayout.LayoutParams p=new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,
						LinearLayout.LayoutParams.WRAP_CONTENT);		
				
				m_Layout.addView(textView,p);
				Button buttonView=new Button(ScrollActivity.this);
				buttonView.setText("Button"+mIndex++);
				m_Layout.addView(buttonView,p);
				buttonView.setOnKeyListener(new View.OnKeyListener() {
					
					@Override
					public boolean onKey(View v, int keyCode, KeyEvent event) {
						// TODO Auto-generated method stub
						if(keyCode==KeyEvent.KEYCODE_DPAD_DOWN&&event.getAction()==KeyEvent.ACTION_DOWN)
						{
							findViewById(R.id.button1).requestFocus();
							return true;							
						}					
						return false;
					}
				});	
				m_Handler.post(mScrollToButton);
			}			
		});
	  m_Button.setOnKeyListener(mAddButtonKeyListener);
				
	}
	
	private Runnable mScrollToButton=new Runnable(){//定义线程体
		@Override
		public void run() {
			// TODO Auto-generated method stub
			int off=m_Layout.getMeasuredHeight()-m_ScrollView.getHeight();
			if(off>0){
				m_ScrollView.scrollTo(0, off);
			}
		}
	};
	private View.OnKeyListener mAddButtonKeyListener = new Button.OnKeyListener(){

		@Override
		public boolean onKey(View v, int keyCode, KeyEvent event) {
			// TODO Auto-generated method stub
			View viewToFucos=null;
			if(event.getAction()==KeyEvent.ACTION_DOWN)
			{
				int iCount=m_Layout.getChildCount();
				switch(keyCode)
				{
				case KeyEvent.KEYCODE_DPAD_UP:
					if(iCount>0){
						viewToFucos=m_Layout.getChildAt(iCount-1);						
					}
					break;
				case KeyEvent.KEYCODE_DPAD_DOWN:
					if(iCount<m_Layout.getWeightSum())
					{
						viewToFucos=m_Layout.getChildAt(iCount+1);
						
					}
					break;
				default:
					break;
				}				
			}
			if(viewToFucos!=null)
			{
				viewToFucos.requestFocus();
				return true;
			}
			else			
			return false;
		}		
	};
}
           

实现的效果，每点一下button按钮，就会增加一个线性布局。  实现了动态的增加控件.

1> LinearLayout.LayoutParams p 设置布局的参数, 调用addView方法时加入这个参数,就会按这个布局方式显示.

2> m_Layout.addView(textView,p);  往Layout布局中加入一个控件.

3> findViewById(R.id.button1). requestFocus();   申请获得焦点.

4> Button.setOnClickListener  点击监听,  buttonView.setOnKeyListener   按键监听.