我的应用程序在启动时加载了很多东西,经过测试,它在开始时延迟太久而没有splash screen
。所以,我希望在我的应用加载完成之前显示splash screen
。我不希望在X秒内显示带有计时器的屏幕。我在这里找到了一个例子:
我尝试在上面的SO主题中实现代码,但我不理解代码。在将它集成到我的代码中后,我想出了一个错误,我在下面的代码中注释了它。但我不了解很多代码,我在下面的代码中评论了我感到困惑的部分。
public class MainMenu extends Activity {
private ProgressDialog pd = null;
private Object data = null; //What is this?
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.mainmenu);
// show the ProgressDialog on this thread
this.pd = ProgressDialog.show(this, "Working...", "Downloading data...", true, false);
// start a new thread that will download all the data
new DownloadTask().execute("Any parameters to download."); //What is DownloadTask()?
}
private class DownloadTask extends AsyncTask<String, Void, Object> {
protected Object doInBackground(String... args) { //Are these parameters correct?
return "replace this with your object"; //What is this?
}
protected void onPostExecute(Object results) {
// pass the resulting data to the main activity
MainMenu.this.data = result; //Error: "result cannot be resolved to a variable"
if(MainMenu.this.pd != null) {
MainMenu.this.pd.dismiss();
}
}
}
}
答案 0 :(得分:3)
让我们从错误开始:
MainMenu.this.data = result;
注意拼写错误?它应该是结果* s *:
MainMenu.this.data = results;
解决下面的其余问题:
private class DownloadTask extends AsyncTask<String, Void, Object>
声明适用于名为DownloadTask
的内联类,它声明您将String
(通过String...
)作为doInBackground(String... params)
的参数。
第二个参数(在您的情况下为Void
)表示用于通过publishProgress(DATATYPE)
/ onProgressUpdate(DATATYPE... progress)
“发布”进度的数据类型。此方法适用于通知用户更改,例如,当您下载完文件但仍有少量文件时。
最后一个参数(Object
)表示您将传递给onPostExecute(DATATYPE)
的数据类型,在此示例中为Object
。这可以是在某处更新ListAdapter,也可以根据doInBackground
中完成的操作的结果触发任何其他UI更改。
答案 1 :(得分:2)
在ProgressDialog
中显示onPreexecute
并在onPostExcute
方法中将其关闭
类似这样的事情
private class DownloadTask extends AsyncTask<String, Void, Object> {
@Override
protected void onPreExecute() {
mProgressDialog = new ProgressDialog(activity);
mProgressDialog =ProgressDialog.show(activity, "", "Please Wait",true,false);
super.onPreExecute();
}
protected Object doInBackground(String... args) { //Are these parameters correct?
return "replace this with your object"; //What is this?
}
protected void onPostExecute(Object results) {
// pass the resulting data to the main activity
MainMenu.this.data = results; //it should be results
if (mProgressDialog != null || mProgressDialog.isShowing()){
mProgressDialog.dismiss();
}
if(MainMenu.this.pd != null) {
MainMenu.this.pd.dismiss();
}
}