Android隐式抽屉及缩放控制（20）

• SlidingDrawer是一种抽屉型组件，当用户打开这个小抽屉以后会出一个大礼包，就是一系列的程序集，玩过手机版的植物大战僵尸的知道手机界面本来就小，而为了节省空间就会用一个小小抽屉或箭头标志，这样就解决了布局空间紧张问题。

其方法有这几种：

首先定义main.xml布局文件：

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

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
      <SlidingDrawer
           android:orientation="horizontal" 
        android:id="@+id/slidingdrawer1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:content="@+id/content"
        android:handle="@+id/handle" >

        <ImageView
			android:id="@+id/handle"
			android:src="@drawable/ic"
			android:layout_width="wrap_content"
			android:layout_height="wrap_content" />

        <LinearLayout
            android:id="@+id/content"
            android:orientation="vertical" 
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" >
        </LinearLayout>
    </SlidingDrawer>
    

</RelativeLayout>

 之后我们想要添加的组件添加到linearlayout：content里面，它相当于抽屉，把软件程序集藏得好好地，图片imageview相当于抽屉拉手，一个标志作用

现在定义Activity：

public class MainActivity extends Activity {

	
	private SlidingDrawer slid=null;
	private ImageView image=null;
	private ImageView handle=null;
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		image=new ImageView(this);
		image.setImageResource(R.drawable.draw);
		
		LinearLayout layout = (LinearLayout) super.findViewById(R.id.content) ;	
		layout.addView(image);
		this.slid = (SlidingDrawer) super.findViewById(R.id.slidingdrawer1) ;
		this.handle = (ImageView) super.findViewById(R.id.handle) ;
		//打开隐藏抽屉
		this.slid.setOnDrawerOpenListener(new OnDrawerOpenListenerImpl()) ;
		//关闭隐藏抽屉
		this.slid.setOnDrawerCloseListener(new OnDrawerCloseListenerImpl()) ;
		//拖动隐藏抽屉组件
		this.slid.setOnDrawerScrollListener(new OnDrawerScrollListenerImpl()) ;
	}
	private class OnDrawerOpenListenerImpl implements OnDrawerOpenListener {

		@Override
		public void onDrawerOpened() {
			MainActivity.this.handle.setImageResource(R.drawable.right) ;
		}
		
	}
	
	private class OnDrawerCloseListenerImpl implements OnDrawerCloseListener {

		@Override
		public void onDrawerClosed() {
			MainActivity.this.handle.setImageResource(R.drawable.ic) ;
		}
		
	}
	
	private class OnDrawerScrollListenerImpl implements OnDrawerScrollListener {

		@Override
		public void onScrollEnded() {
			Toast.makeText(MainActivity.this, "窗口拖动结束。", Toast.LENGTH_SHORT).show() ;
		}

		@Override
		public void onScrollStarted() {
			Toast.makeText(MainActivity.this, "正在拖动窗口。", Toast.LENGTH_SHORT).show() ;
		}
		
	}


	@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;
	}

}

 
 

 


 
 这里为了简单起见只显示一张图片，读者可以随意加组件。

 

• 缩放组件

就是下面这个组件

现在我们来完成一个实例，文字放大器，这一方面做好了我们就能轻松实现图片放大缩小了

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <ZoomControls
        android:id="@+id/zoomControls1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

 Activity代码：

public class MainActivity extends Activity {

	private ZoomControls zoomControls;
	private int size;
	private TextView text;
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		this.zoomControls=(ZoomControls)super.findViewById(R.id.zoomControls);
		this.text=(TextView)super.findViewById(R.id.text);
		this.zoomControls.setOnZoomInClickListener(new ZoomIn());
		
		this.zoomControls.setOnZoomOutClickListener(new ZoomOut());		
				
				
	}
	//更改文字大小
	private class  ZoomIn implements OnClickListener{

		@Override
		public void onClick(View arg0) {
			// TODO Auto-generated method stub
			MainActivity.this.size=size+2;
			MainActivity.this.text.setTextSize(size);
			
		}
		
	}
	//更改文字大小
	private class  ZoomOut implements OnClickListener{

		@Override
		public void onClick(View arg0) {
			// TODO Auto-generated method stub
			MainActivity.this.size=size-2;
			MainActivity.this.text.setTextSize(size);
			
		}
		
	}

	@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;
	}

}

 仔细发现缩放组件其实就是按钮，所用的监听方法也是按钮的，那么得到的启示就是我们可以用更漂亮的imagebutton来实现这个功能，这就交给读者朋友们。

实现效果如下：