Android笔记-ContentProvider call方法

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  • ContentProvider call方法 使用.

  • 资料来源:

    https://developer.android.com/guide/topics/providers/content-providers
    https://juejin.im/entry/5a4c39605188257c4d1b8a4a

  • 更新

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     20.04.17 初始化
    21.02.11 添加一个错误修正
    21.02.13 补充完整

导语

  • 开始实现的 NoWakeLock 使用了 ContentProvider 标准的查询和插入,结果实在不尽如人意.太死板了.
  • 进入瓶颈,去翻 Xprivacylua 的源码,发现 Xprivacylua 也使用了 ContentProvider ,不过大段是自定义的 call 方法.
  • 从网上资料来看,call 方法确实灵活多了,也是同步的调用,底层与查询/插入都是一样的实现.传输数据一次不能超过 1M.传输的数据需要可序列化.

声明 ContentProvider

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class DSContentProvider : ContentProvider() {  
    override fun onCreate(): Boolean {  
        return true  
 }  
  
    override fun call(method: String, arg: String?, extras: Bundle?): Bundle? {  
        //无序处理  
 if (extras == null) {  
            return null  
 }  
        return context?.let { ProviderHandler.getInstance(it).getMethod(method, extras) }  
 }  
  
    override fun query(  
        uri: Uri, projection: Array<String>?, selection: String?,  
 selectionArgs: Array<String>?, sortOrder: String?  
    ): Cursor? {  
        return null  
 }  
  
    override fun insert(uri: Uri, values: ContentValues?): Uri? {  
        return uri  
    }  
  
    override fun delete(uri: Uri, selection: String?, selectionArgs: Array<String>?): Int {  
        return 0  
 }  
  
    override fun getType(uri: Uri): String? {  
        return null  
 }  
  
    override fun update(  
        uri: Uri, values: ContentValues?, selection: String?,  
 selectionArgs: Array<String>?  
    ): Int {  
        return 0  
 }  
}

在 AndroidManifest.xml -> application 下声明

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<provider
     android:name=".data.provider.DSContentProvider"
     android:authorities="com.js.deepsleep"
     android:enabled="true"
     android:exported="false" />

call 方法

  • fun call(method: String, arg: String?, extras: Bundle?): Bundle? {}

    • method: String 一般是我们自定义 call 方法的方法名.
    • arg: String? 大概是可有可无的字段.
    • extras: Bundle? 传输数据的载体,需要从 Bundle 中取出对应数据.

  • 实际的例子也非常简单

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    override fun call(method: String, arg: String?, extras: Bundle?): Bundle? {
        //no need handler
        if (extras == null) {
            return null
        }
        return context?.let { ProviderHandler.getInstance(it).getMethod(method, extras) }
    }

  • 传入 method 到具体的 Handler,再根据具体的方法名,执行获取结果.(kt 真香😂)

  • 以一个 test 方法为例,因为 call 方法要求返回一个 Bundle? 这里直接返回了 “Test”.

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    @VisibleForTesting
    fun test(bundle: Bundle): Bundle? {
      val test = bundle.get("Test") as String?

      LogUtil.d(TAG, "$test")

      val tmp = Bundle()
      tmp.putString("Test", "Test")
      return tmp
    }

  • 调用 Test 方法

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    fun getMethod(methodName: String, bundle: Bundle): Bundle? {
      return when (methodName) {
        "test" -> test(bundle)
        else -> null
      }
    }

  • AndroidTest 类

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    class NWLContentProviderTest {
      private var mContentResolver: ContentResolver? = null
      private val authority = "com.js.nowakelock"

      @Before
      fun setUp() {
          val context = ApplicationProvider.getApplicationContext<Context>()
          mContentResolver = context.contentResolver
      }

      @Test
      fun call() {
          val method = "test"
          val url = Uri.parse("content://$authority")

          val extras = Bundle()
          extras.putString("Test", "Test")

          val bundle = mContentResolver?.call(url, method, null, extras)
          //if (bundle != null) {
          //    LogUtil.d("test1", bundle.toString())
          //}
          assertEquals(bundle!!.getString("Test"), "Test")
      }
    }

  • 执行测试,取回的结果也是 “Test”.

AndroidX.test dependency error

参考 Set up project for AndroidX Test 添加 Android X Test 依赖

运行 NWLContentProviderTest 会提示错误:

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Execution failed for task ':app:processDebugAndroidTestManifest'.
> Could not resolve all files for configuration ':app:debugAndroidTestRuntimeClasspath'.
   > Could not resolve androidx.test:core:1.3.0.
     Required by:
         project :app
         project :app > androidx.test.ext:junit:1.1.2
         project :app > androidx.test.ext:truth:1.3.0
         project :app > androidx.test.espresso:espresso-intents:3.3.0
      > Cannot find a version of 'androidx.test:core' that satisfies the version constraints:
           Dependency path 'DeepSleep:app:unspecified' --> 'androidx.test:core:1.3.0'
           Constraint path 'DeepSleep:app:unspecified' --> 'androidx.test:core:{strictly 1.2.0}' because of the following reason: debugRuntimeClasspath uses version 1.2.0
           Dependency path 'DeepSleep:app:unspecified' --> 'androidx.test.ext:junit:1.1.2' --> 'androidx.test:core:1.3.0'
           Dependency path 'DeepSleep:app:unspecified' --> 'androidx.test.ext:truth:1.3.0' --> 'androidx.test:core:1.3.0'
           Dependency path 'DeepSleep:app:unspecified' --> 'androidx.test.espresso:espresso-intents:3.3.0' --> 'androidx.test:core:1.3.0'

参考 AndroidX.test dependency error 发现是 androidx.fragment:fragment-testing 要求核心版本是 1.2…这不是大水冲了龙王庙吗…

原帖的解决方案没太看懂,反正先注释掉 androidx.fragment:fragment-testing 目前没有再使用.

结语

  • 为了个 IPC 还折腾了 aidl + service. 还有 call 配合 service,加上之前的 XSharedPreferences ,几乎把android ipc 折腾全了…
  • 之后就是填坑了,希望能尽快填完.