[代码例程] Android效果之 抽屉效果

在Android开发过程中，我们喜欢使用特效，比如抽屉效果，这样可以给人很好的体验。点击一个按钮，就像拉抽屉一样展开界面，这样的效果正是我在这里所要说明的。比如在AVD或真机上，我们都有看过这种效果。比较常用的应用是LAUNCH应用。在这个应用中我们实现了拉抽屉呈现所有的程序。那么我们就来开始实现这个让我们梦寐以求的效果吧。我们先创建一个工程。在这里我命名为drawerDemo.在这个例子中我在main.xml文件中写入如下，那么大家就来看看代码吧：

Java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"

>



<SlidingDrawer

android:id="@+id/slidingdrawer"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical"

android:handle="@+id/handle"

android:content="@+id/content">





<Button

android:id="@+id/handle"

android:layout_width="88dip"

android:layout_height="44dip"

android:background="@drawable/handle" />



<LinearLayout

android:id="@+id/content"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:background="#00ff00">



<GridView

android:id="@+id/allapps"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

/>



</LinearLayout>

</SlidingDrawer>

</LinearLayout>
复制代码看到这个SlidingDrawer控件。就像使用Button,TextView一样简单使用。然后在LauncherActivity.java代码如下：

Java代码：public class LauncherActivity extends Activity implements OnItemClickListener{



private GridView mGridView;

private Context mContext;

private PackageManager mPackageManager;

private List<ResolveInfo> mAllApps;



public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

setupViews();

}



public void setupViews(){

mContext = LauncherActivity.this;

mPackageManager = getPackageManager(); //包管理器

mGridView = (GridView)findViewById(R.id.allapps);

bindAllApps();

mGridView.setAdapter(new GridItemAdapter(mContext, mAllApps));

mGridView.setNumColumns(4);

mGridView.setOnItemClickListener(this);

}



public void bindAllApps(){

//这里是关键哦，我们平时写的应用总有一个activity申明成这两个属性

//也就是应用的入口

Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);

mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);



//符合上面条件的全部查出来,并且排序

mAllApps = mPackageManager.queryIntentActivities(mainIntent, 0);

Collections.sort(mAllApps, new ResolveInfo.DisplayNameComparator(mPackageManager));

}



//gridview点击事件，点击进入相关应用

@Override

public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

// TODO Auto-generated method stub

ResolveInfo res = mAllApps.get(position);

//该应用的包名和主Activity

String pkg = res.activityInfo.packageName;

String cls = res.activityInfo.name;

ComponentName componet = new ComponentName(pkg, cls);

Intent i = new Intent();

i.setComponent(componet);

startActivity(i);

}



//不明白BaseAdapter的用法 我高手进阶里有

private class GridItemAdapter extends BaseAdapter{

private Context context;

private List<ResolveInfo> resInfo;

//构造函数

public GridItemAdapter(Context c,List<ResolveInfo> res){

context = c;

resInfo = res;

}



@Override

public int getCount() {

// TODO Auto-generated method stub

return resInfo.size();

}



@Override

public Object getItem(int position) {

// TODO Auto-generated method stub

return null;

}



@Override

public long getItemId(int position) {

// TODO Auto-generated method stub

return 0;

}



@Override

public View getView(int position, View convertView, ViewGroup parent) {

//不明白LayoutInflater的我android高手进阶里有

convertView = LayoutInflater.from(context).inflate(R.layout.application_layout, null);

ImageView app_icon = (ImageView)convertView.findViewById(R.id.app_icon);

TextView app_tilte = (TextView)convertView.findViewById(R.id.app_title);

ResolveInfo res = resInfo.get(position);

app_icon.setImageDrawable(res.loadIcon(mPackageManager));

app_tilte.setText(res.loadLabel(mPackageManager).toString());

return convertView;

}



}

}