背景
每次在StudyDemos工程里，添加知识点Demo时，总有一部分工作是重复的，那就是在首页添加入口。省掉这个重复添加的过程就是我的目的。
实现思路
与APIDemo App类似，实现思路如下：
- 对manifest里的activity添加两个约定，查找规范和目录规范
- 首页自动扫描上面特定的intent-filter，获取Demo列表和名称
- 通过RecyclerView显示，同时支持多级目录
效果如下所示：
此Demo的源码：AndroidStudyDemo
实现过程
查找规范和目录规范
查找规范：通过指定特殊的intent-filter实现过滤出真正的Demo Activity，复用Android已有的SAMPLE_CODE类别，如下所示：
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| <intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.SAMPLE_CODE"/>
</intent-filter>
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目录规范：通过“/”分割多级目录和名称，如下所示：
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| android:label="Binder/AIDL例子"
|
首页显示
由于有目录的概念，不是简单的查找出所有的Demo Activity后直接显示，需要判断类型：
- 当前如果是目录，跳转的Intent还首页，但只显示当前目录下的子目录或Demo
- 当前如果是Demo，跳转的Intent就是Demo界面
查询所有的Demo
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| val intent: Intent = Intent(Intent.ACTION_MAIN)
.addCategory(Intent.CATEGORY_SAMPLE_CODE)
.setPackage(this.packageName)
val list: List<ResolveInfo> =
this.packageManager.queryIntentActivities(intent, 0) ?: return demos
|
对所有的Demo进行过滤处理，只获取当前目录下的子目录或Demo
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| private fun getData(prefix: String): MutableList<DemosAdapter.Demo> {
val demos: MutableList<DemosAdapter.Demo> = mutableListOf<DemosAdapter.Demo>()
val intent: Intent = Intent(Intent.ACTION_MAIN)
.addCategory(Intent.CATEGORY_SAMPLE_CODE)
.setPackage(this.packageName)
val list: List<ResolveInfo> =
this.packageManager.queryIntentActivities(intent, 0) ?: return demos
var prefixPath: List<String>? = null
var prefixWithSlash: String = prefix
if(prefix != "") {
prefixPath = prefix.split("/")
prefixWithSlash = "$prefix/"
}
val map:MutableMap<String, Boolean> = mutableMapOf<String, Boolean>()
for (info in list) {
val label:String = info.activityInfo.loadLabel(this.packageManager).toString()
if(prefixPath == null || label.startsWith(prefixWithSlash)) {
val labelPath = label.split("/")
val nextLabel: String = labelPath[prefixPath?.size ?: 0]
if ((prefixPath?.size ?: 0) == (labelPath.size - 1)) {
val result = Intent()
result.setClassName(info.activityInfo.packageName, info.activityInfo.name)
demos.add(DemosAdapter.Demo(nextLabel, result))
} else {
if(map.get(nextLabel) == null){
val result = Intent(this, StudyDemos::class.java)
result.putExtra("com.example.android.apis.Path", if(prefix == "") nextLabel else "${prefix}/${nextLabel}")
demos.add(DemosAdapter.Demo(nextLabel, result))
map.put(nextLabel, true)
}
}
}
}
return demos
}
|
RecyclerView显示
初始化RecyclerView
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| val recyclerView: RecyclerView = findViewById<RecyclerView>(R.id.recycler_view)
recyclerView.setHasFixedSize(true)
val linearLayoutManager = LinearLayoutManager(this)
linearLayoutManager.orientation = LinearLayoutManager.VERTICAL
recyclerView.layoutManager = linearLayoutManager
val demos: MutableList<DemosAdapter.Demo> = getData(path?:"")
recyclerView.adapter = DemosAdapter(demos, object: DemosAdapter.OnItemClickListener {
override fun onClick(holder: DemosAdapter.DemosViewHolder, demo: DemosAdapter.Demo) {
this@StudyDemos.startActivity(demo.intent)
}
})
recyclerView.addItemDecoration(DividerItemDecoration(this, DividerItemDecoration.VERTICAL))
|
Adapter：
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| class DemosAdapter(var demos: MutableList<Demo>, var itemClickListener: OnItemClickListener) : RecyclerView.Adapter<DemosAdapter.DemosViewHolder>() {
override fun getItemViewType(position: Int): Int {
return 0
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DemosViewHolder {
val inflater = LayoutInflater.from(parent.context)
val itemView = inflater.inflate(R.layout.item_demo, parent, false)
return DemosViewHolder(itemView)
}
override fun getItemCount(): Int {
return demos.size
}
override fun onBindViewHolder(holder: DemosViewHolder, position: Int) {
val demo = demos[position]
holder.titleView.setText(demo.title)
holder.itemView.setOnClickListener {
itemClickListener.onClick(holder, demo)
}
}
interface OnItemClickListener {
fun onClick(holder: DemosViewHolder, demo: Demo)
}
class Demo(var title: String, var intent: Intent) {}
class DemosViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val titleView: TextView
init {
titleView = itemView.findViewById(R.id.title_view)
}
}
}
|
参考
- ApiDemos
