实现Android 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，在这里我参考一些别人写的博客试例讲这种实现细节。



创建一个工程。在这里我命名为LauncherDemo.在这个例子中我在main.xml文件中写入如下，贴上代码：

android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
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">
android:id="@+id/handle"
android:layout_width="88dip"
android:layout_height="44dip"
android:background="@drawable/handle"
/>
android:id="@+id/content"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#00ff00">


android:id="@+id/allapps"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>




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：
public class LauncherActivity extends Activity implements OnItemClickListener{
private GridView mGridView;
private Context mContext;
private PackageManager mPackageManager;
private List 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 resInfo;

//构造函数
public GridItemAdapter(Context c,List 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;
}

}
}