可动态布局的Android抽屉之基础
最后更新于：2022-04-01 15:47:42
本文来自[http://blog.csdn.net/hellogv/](http://blog.csdn.net/hellogv/) ，欢迎转摘，引用必须注明出处！
以前曾经介绍过[《Android提高第十九篇之"多方向"抽屉》](http://blog.csdn.net/hellogv/article/details/6264706)，当这个抽屉组件不与周围组件发生压挤的情况下(周围组件布局不变)，是比较好使的，但是如果需要对周围组件挤压，则用起来欠缺美观了。
如下图。在对周围压挤的情况下，抽屉是先把周围的组件一次性压挤，再通过动画效果展开/收缩的，这种做法的好处是快速简单，坏处是如果挤压范围过大，则效果生硬。
本文实现的自定义抽屉组件，主要针对这种压挤效果做出改良，渐进式压挤周围组件，使得过渡效果更加美观。如下图。
本文实现的抽屉原理是酱紫：
1.抽屉组件主要在屏幕不可视区域，手柄在屏幕边缘的可视区域。即 抽屉.rightMargin=-XXX + 手柄.width
2.指定一个周围组件为可压挤，即LayoutParams.weight=1;当然用户也可以指定多个View.
3.使用AsyncTask来实现弹出/收缩的动画，弹出：抽屉.rightMargin+=XX，收缩：抽屉.rightMargin-=XX
总结，本文的自定义抽屉虽然对压挤周围组件有过渡效果，但是比较耗资源，读者可以针对不同的情况考虑使用。
**本文的源码可以到**[**http://download.csdn.net/detail/hellogv/3615686**](http://download.csdn.net/detail/hellogv/3615686)** 下载。**
接下来贴出本文全部源代码：
main.xml的源码:
~~~
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:id="@+id/container">
<GridView android:id="@+id/gridview" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:numColumns="auto_fit"
android:verticalSpacing="10dp" android:gravity="center"
android:columnWidth="50dip" android:horizontalSpacing="10dip" />
</LinearLayout>
~~~
GridView的Item.xml的源码：
~~~
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content" android:paddingBottom="4dip"
android:layout_width="fill_parent">
<ImageView android:layout_height="wrap_content" android:id="@+id/ItemImage"
android:layout_width="wrap_content" android:layout_centerHorizontal="true">
</ImageView>
<TextView android:layout_width="wrap_content"
android:layout_below="@+id/ItemImage" android:layout_height="wrap_content"
android:text="TextView01" android:layout_centerHorizontal="true"
android:id="@+id/ItemText">
</TextView>
</RelativeLayout>
~~~
Panel.java是本文核心，抽屉组件的源码，这个抽屉只实现了从右往左的弹出/从左往右的收缩，读者可以根据自己的需要修改源码来改变抽屉动作的方向：
~~~
public class Panel extends LinearLayout{
public interface PanelClosedEvent {
void onPanelClosed(View panel);
}
public interface PanelOpenedEvent {
void onPanelOpened(View panel);
}
/**Handle的宽度，与Panel等高*/
private final static int HANDLE_WIDTH=30;
/**每次自动展开/收缩的范围*/
private final static int MOVE_WIDTH=20;
private Button btnHandle;
private LinearLayout panelContainer;
private int mRightMargin=0;
private Context mContext;
private PanelClosedEvent panelClosedEvent=null;
private PanelOpenedEvent panelOpenedEvent=null;
/**
* otherView自动布局以适应Panel展开/收缩的空间变化
* @author GV
*
*/
public Panel(Context context,View otherView,int width,int height) {
super(context);
this.mContext=context;
//改变Panel附近组件的属性
LayoutParams otherLP=(LayoutParams) otherView.getLayoutParams();
otherLP.weight=1;//支持压挤
otherView.setLayoutParams(otherLP);
//设置Panel本身的属性
LayoutParams lp=new LayoutParams(width, height);
lp.rightMargin=-lp.width+HANDLE_WIDTH;//Panel的Container在屏幕不可视区域，Handle在可视区域
mRightMargin=Math.abs(lp.rightMargin);
this.setLayoutParams(lp);
this.setOrientation(LinearLayout.HORIZONTAL);
//设置Handle的属性
btnHandle=new Button(context);
btnHandle.setLayoutParams(new LayoutParams(HANDLE_WIDTH,height));
btnHandle.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View arg0) {
LayoutParams lp = (LayoutParams) Panel.this.getLayoutParams();
if (lp.rightMargin < 0)// CLOSE的状态
new AsynMove().execute(new Integer[] { MOVE_WIDTH });// 正数展开
else if (lp.rightMargin >= 0)// OPEN的状态
new AsynMove().execute(new Integer[] { -MOVE_WIDTH });// 负数收缩
}
});
//btnHandle.setOnTouchListener(HandleTouchEvent);
this.addView(btnHandle);
//设置Container的属性
panelContainer=new LinearLayout(context);
panelContainer.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
this.addView(panelContainer);
}
/**
* 定义收缩时的回调函数
* @param event
*/
public void setPanelClosedEvent(PanelClosedEvent event)
{
this.panelClosedEvent=event;
}
/**
* 定义展开时的回调函数
* @param event
*/
public void setPanelOpenedEvent(PanelOpenedEvent event)
{
this.panelOpenedEvent=event;
}
/**
* 把View放在Panel的Container
* @param v
*/
public void fillPanelContainer(View v)
{
panelContainer.addView(v);
}
/**
* 异步移动Panel
* @author hellogv
*/
class AsynMove extends AsyncTask<Integer, Integer, Void> {
@Override
protected Void doInBackground(Integer... params) {
int times;
if (mRightMargin % Math.abs(params[0]) == 0)// 整除
times = mRightMargin / Math.abs(params[0]);
else
// 有余数
times = mRightMargin / Math.abs(params[0]) + 1;
for (int i = 0; i < times; i++) {
publishProgress(params);
try {
Thread.sleep(Math.abs(params[0]));
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return null;
}
@Override
protected void onProgressUpdate(Integer... params) {
LayoutParams lp = (LayoutParams) Panel.this.getLayoutParams();
if (params[0] < 0)
lp.rightMargin = Math.max(lp.rightMargin + params[0],
(-mRightMargin));
else
lp.rightMargin = Math.min(lp.rightMargin + params[0], 0);
if(lp.rightMargin==0 && panelOpenedEvent!=null){//展开之后
panelOpenedEvent.onPanelOpened(Panel.this);//调用OPEN回调函数
}
else if(lp.rightMargin==-(mRightMargin) && panelClosedEvent!=null){//收缩之后
panelClosedEvent.onPanelClosed(Panel.this);//调用CLOSE回调函数
}
Panel.this.setLayoutParams(lp);
}
}
}
~~~
main.java是主控部分，演示了Panel的使用：
~~~
public class main extends Activity {
public Panel panel;
public LinearLayout container;
public GridView gridview;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.setTitle("“可动态布局”的抽屉组件之构建基础-----hellogv");
gridview = (GridView) findViewById(R.id.gridview);
container=(LinearLayout)findViewById(R.id.container);
panel=new Panel(this,gridview,200,LayoutParams.FILL_PARENT);
container.addView(panel);//加入Panel控件
//新建测试组件
TextView tvTest=new TextView(this);
tvTest.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT));
tvTest.setText("测试组件，红字白底");
tvTest.setTextColor(Color.RED);
tvTest.setBackgroundColor(Color.WHITE);
//加入到Panel里面
panel.fillPanelContainer(tvTest);
panel.setPanelClosedEvent(panelClosedEvent);
panel.setPanelOpenedEvent(panelOpenedEvent);
//往GridView填充测试数据
ArrayList<HashMap<String, Object>> lstImageItem = new ArrayList<HashMap<String, Object>>();
for (int i = 0; i < 100; i++) {
HashMap<String, Object> map = new HashMap<String, Object>();
map.put("ItemImage", R.drawable.icon);
map.put("ItemText", "NO." + String.valueOf(i));
lstImageItem.add(map);
}
SimpleAdapter saImageItems = new SimpleAdapter(this,
lstImageItem,
R.layout.item,
new String[] { "ItemImage", "ItemText" },
new int[] { R.id.ItemImage, R.id.ItemText });
gridview.setAdapter(saImageItems);
gridview.setOnItemClickListener(new ItemClickListener());
}
PanelClosedEvent panelClosedEvent =new PanelClosedEvent(){
@Override
public void onPanelClosed(View panel) {
Log.e("panelClosedEvent","panelClosedEvent");
}
};
PanelOpenedEvent panelOpenedEvent =new PanelOpenedEvent(){
@Override
public void onPanelOpened(View panel) {
Log.e("panelOpenedEvent","panelOpenedEvent");
}
};
class ItemClickListener implements OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> arg0,View arg1, int arg2, long arg3) {
@SuppressWarnings("unchecked")
HashMap<String, Object> item = (HashMap<String, Object>) arg0
.getItemAtPosition(arg2);
setTitle((String) item.get("ItemText"));
}
}
~~~
后面还会继续介绍如何在Panel加入拖拉效果的处理！