标题翻译
Android Studio - Make an activity wait until loading UI
问题
我有一个包含`recyclerView`的活动，该`recyclerView`从数据库加载数据。有时在启动活动时，直到重新加载活动后才看到数据。
我尝试做的是显示一个加载动画持续 3 秒钟，等待数据加载完成，然后再显示数据。
我将以下内容添加到我的 XML 中：
<RelativeLayout
android:id="@+id/loadingPanel"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center" >
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:indeterminate="true" />
</RelativeLayout>
但是如何使我的活动等待 3 秒钟（显示加载动画），然后返回到已加载数据的活动？
英文翻译
I have an activity which contains a recyclerView that loads data from the database. Sometimes when starting the activity I don't see the data until reloading the activity.
What I'm trying to do is show a loading animation for 3 seconds and wait for it to load then show it.
I added this to my xml:
<RelativeLayout
android:id="@+id/loadingPanel"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center" >
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:indeterminate="true" />
</RelativeLayout>
But how can I make my activity wait for 3 seconds (showing the loading animation) and then go back to the activity with loaded data?
答案1
得分: 0
-
创建一个回调类：
interface Callback { public void onStart(); public void onComplete(<your_data_type> data); } -
将回调作为参数添加到你的方法中，该方法从数据库加载数据，然后在事件发生时需要调用回调的方法：
public void loadData(Callback callback) { callback.onStart(); <your_data_type> data = /* 从数据库加载数据 */; callback.onComplete(data); } -
将一个实现了回调的对象传递给
loadData方法：loadData(new Callback { public void onStart() { // 开始显示进度条 } public void onComplete(<your_data_type> data) { // 在你的可循环视图中显示数据 // 隐藏进度条 } });
当然，你需要在后台线程中调用loadData()方法，并在主线程中调用回调的方法。
英文翻译
-
Create a callback class:
interface Callback {
public void onStart();
public void onComplete(<your_data_type> data);
} -
Add a callback as an argument to your method, that loads data from database, then you need to call the callback's methods when the events happen:
public void loadData(Callback callback) {
callback.onStart();
<your_data_type> data = /* load data from database */;
callback.onComplete(data);
} -
Pass it an implemented callback to loadData method:
loadData(new Callback {});
public void onStart() {
// start showing your progress bar
}
public void onComplete(<your_data_type> data) {
// show data in your recycler view
// hide your progress bar
}
And of course you need to call loadData() method in a background thread and call the callback's methods in a main thread.
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