{"id":319,"date":"2020-03-27T16:44:42","date_gmt":"2020-03-27T08:44:42","guid":{"rendered":"https:\/\/badgameshow.com\/fly\/?p=319"},"modified":"2023-02-03T11:20:30","modified_gmt":"2023-02-03T03:20:30","slug":"android-jetpack-livedata","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/fly\/android-jetpack-livedata\/","title":{"rendered":"\ud83d\udcc8\u3010Jetpack\u3011Android LiveData \u5b58\u6d3b\u8cc7\u6599 \u7bc4\u4f8b\ud83d\udcbb"},"content":{"rendered":"<h1>\ud83d\udcc8\u3010Jetpack\u3011Android LiveData \u5b58\u6d3b\u8cc7\u6599 \u7bc4\u4f8b\ud83d\udcbb<\/h1>\n<h4>LiveData \u662f\u5728 Android \u6846\u67b6\u4e2d\u63a8\u51fa\u7684\u4e00\u500b\u65b0\u6280\u8853\uff0c\u5b83\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u5728 Android \u4e2d\u5be6\u73fe\u8cc7\u6599\u72c0\u614b\u548c UI \u8cc7\u6599\u7d81\u5b9a\u3002<\/h4>\n<h4>\u5b83\u6975\u5927\u5730\u6539\u5584\u4e86\u958b\u767c\u8005\u8207 UI \u548c\u8cc7\u6599\u4e4b\u9593\u7684\u96d9\u5411\u7d81\u5b9a\uff0c\u4e26\u4e14\u5177\u6709\u5f88\u5f37\u7684\u751f\u547d\u9031\u671f\u610f\u8b58\uff0c\u9019\u80fd\u8b93\u958b\u767c\u8005\u66f4\u8f15\u9b06\u5730\u69cb\u5efa\u4e26\u4fdd\u6301\u5176 Android \u61c9\u7528\u7a0b\u5f0f\u7684\u6574\u500b\u751f\u547d\u9031\u671f\u4e2d\u7684 UI\u3002<\/h4>\n<h4>LiveData \u540c\u6642\u80fd\u6190\u611b\u958b\u767c\u8005\uff0c\u8b93\u4ed6\u5011\u53ea\u9700\u8981\u91dd\u5c0d\u5f8c\u7aef\u8cc7\u6599\u7684\u66f4\u6539\u505a\u61c9\u5c0d\uff0c\u800c\u4e0d\u7528\u64d4\u5fc3\u91cd\u65b0\u8f09\u5165\u548c\u91cd\u7e6a\u6574\u500b UI\u3002<\/h4>\n<hr \/>\n<h4>\u6587\u7ae0\u76ee\u9304<\/h4>\n<ol>\n<li><a href=\"#a\">LiveData ViewModel<\/a><\/li>\n<li><a href=\"#b\">LiveData<\/a><\/li>\n<li><a href=\"#c\">Developer Documents LiveData<\/a><\/li>\n<\/ol>\n<hr \/>\n<p><a id=\"a\"><\/a><\/p>\n<h4>1.LiveData ViewModel<\/h4>\n<h5>Person.kt<\/h5>\n<pre><code class=\"language-kotlin line-numbers\">data class Person(\n    val name: String = \"\",\n    val age: Int = 0\n)\n<\/code><\/pre>\n<h5>PersonViewModel.kt<\/h5>\n<pre><code class=\"language-kotlin line-numbers\">class PersonViewModel : ViewModel() {\n\n    private val _name = MutableLiveData&lt;String&gt;()\n    val name: LiveData&lt;String&gt; = _name\n\n    private val _person = MutableLiveData&lt;Person&gt;()\n    val person: LiveData&lt;Person&gt; = _person\n\n    fun changeValue() {\n        _name.value = \"wade\"\n        _person.value = Person(\"wade\", 25)\n    }\n}\n<\/code><\/pre>\n<p><a id=\"b\"><\/a><\/p>\n<h4>2.LiveData<\/h4>\n<h5>build.gradle<\/h5>\n<pre><code class=\"language-groovy line-numbers\">dependencies {\n    def fragment_version = \"1.5.5\"\n    implementation \"androidx.fragment:fragment-ktx:$fragment_version\"\n}\n<\/code><\/pre>\n<h5>MainActivity.kt<\/h5>\n<pre><code class=\"language-kotlin line-numbers\">class MainActivity : AppCompatActivity() {\n\n    private val viewModel: PersonViewModel by viewModels()\n\n    override fun onCreate(savedInstanceState: Bundle?) {\n        super.onCreate(savedInstanceState)\n        setContentView(R.layout.activity_main)\n\n        viewModel.name.observe(this) { name -&gt;\n            Toast.makeText(this, name, Toast.LENGTH_SHORT).show()\n        }\n\n        viewModel.person.observe(this) { person -&gt;\n            Toast.makeText(this, \"<span class=\"katex math inline\">{person.name}<\/span>{person.age}\", Toast.LENGTH_SHORT).show()\n        }\n\n        viewModel.changeValue()\n    }\n}\n<\/code><\/pre>\n<p><a id=\"c\"><\/a><\/p>\n<h4>3.Developer Documents LiveData<\/h4>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/developer.android.com\/topic\/libraries\/architecture\/livedata\" title=\"Open in Documents LiveData\" target=\"_blank\" rel=\"noopener\">Open in Documents LiveData<\/a><\/p>\n\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div>","protected":false},"excerpt":{"rendered":"<p>\ud83d\udcc8\u3010Jetpack\u3011Android LiveData \u5b58\u6d3b\u8cc7\u6599 \u7bc4\u4f8b\ud83d\udcbb LiveData \u662f\u5728 Android &hellip; <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"pgc_sgb_lightbox_settings":"","footnotes":""},"categories":[106],"tags":[13,107,43],"class_list":["post-319","post","type-post","status-publish","format-standard","hentry","category-jetpack","tag-android","tag-jetpack","tag-livedata"],"_links":{"self":[{"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/posts\/319","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/comments?post=319"}],"version-history":[{"count":11,"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/posts\/319\/revisions"}],"predecessor-version":[{"id":1840,"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/posts\/319\/revisions\/1840"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/media?parent=319"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/categories?post=319"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/fly\/wp-json\/wp\/v2\/tags?post=319"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}