当我在Android Studio中运行我的应用时，一切都正常运行。通过运行RushSearch（）查询正确填充抽屉中的ListView。 但是当我创建了apk并且我在我的智能手机上安装以尝试运行应用程序时，第一次运行时Drawer中的ListView没有填充。如果我关闭应用程序并再次运行它，一切都是正确的。
为什么会出现这种异常？
MainActivity.java类上的onCreate方法的代码是这个
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
callWebservice();
// Layout principale col drawer
setContentView(R.layout.activity_main_drawer);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
leftArrow = (ImageView) findViewById(R.id.left_arrow);
titolo = (TextView) findViewById(R.id.titolo_id);
ActionBarDrawerToggle actionBarDrawerToggle =
new ActionBarDrawerToggle(this, drawerLayout, toolbar,
R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawerLayout.setDrawerListener(actionBarDrawerToggle);
actionBarDrawerToggle.syncState();
drawerListView = (ListView) findViewById(R.id.drawer_listView);
// SELECT * FROM Sections where Fk == 0;
sectionsList = new RushSearch().whereEqual("Fk", 0).find(Sections.class);
Log.d("ELEMENTI",""+sectionsList.size());
drawerListViewAdapter = new DrawerListViewAdapter(sectionsList, getApplicationContext());
// Adapter che si occupa di popolare il drawer
drawerListView.setAdapter(drawerListViewAdapter);
// Listner per il click su un elemento del drawer
drawerListView.setOnItemClickListener(click);
}
方法callWebservice（）负责从url获取JSON文件，其代码是这个
private void callWebservice() {
String tag_json_obj = "GetItem";
String url = String.format("http://digitalbox.getsandbox.com/item");
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
saveSections(response.getJSONArray("Sections"));
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Settings", "Error: " + error.getMessage());
}
}) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> headers = new HashMap<String, String>();
headers.put("Content-Type", "application/json");
headers.put("Accept", "application/json");
return headers;
}
};
NetworkController.getInstance().addToRequestQueue(jsonObjectRequest, tag_json_obj);
}
private void saveSections(final JSONArray section) {
Thread t = new Thread(new Runnable() {
@Override
public void run() {
int c = section.length();
for (int i = 0; i < c; i++) {
try {
JSONObject obj = section.getJSONObject(i);
Sections s = new RushSearch().whereEqual("ID", obj.getInt("ID")).findSingle(Sections.class);
if (s == null) {
s = new Sections();
s.setID(obj.getInt("ID"));
}
if (!obj.isNull("Fk"))
s.setFk(obj.getInt("Fk"));
s.setTitle(obj.getString("Title"));
if (!obj.isNull("CategoryColor"))
s.setCategoryColor(obj.getString("CategoryColor"));
s.setPos(obj.getInt("Pos"));
s.setLanguageId(obj.getInt("LanguageId"));
s.setUnavailableForSend(obj.getBoolean("UnavailableForSend"));
s.save();
} catch (JSONException e) {
e.printStackTrace();
}
}
Log.d("sections", "DB updated");
}
});
t.setPriority(Thread.MIN_PRIORITY);
t.start();
}
如果我使用Android Studio运行应用程序，在AVD智能手机中，我有此日志
11-30 15:21:53.520 2170-2170/? I/art: Not late-enabling -Xcheck:jni (already on)
11-30 15:21:53.520 2170-2170/? I/art: Late-enabling JIT
11-30 15:21:53.558 2170-2170/? I/art: JIT created with code_cache_capacity=2MB compile_threshold=1000
11-30 15:21:53.685 2170-2170/rawpepper.it.digitalbox W/System: ClassLoader referenced unknown path: /data/app/rawpepper.it.digitalbox-2/lib/x86
11-30 15:21:54.099 2170-2170/rawpepper.it.digitalbox W/art: Before Android 4.1, method int android.support.v7.internal.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
11-30 15:21:54.469 2170-2170/rawpepper.it.digitalbox D/ELEMENT: 13
11-30 15:21:54.486 2170-2210/rawpepper.it.digitalbox D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
11-30 15:21:54.592 2170-2210/rawpepper.it.digitalbox I/OpenGLRenderer: Initialized EGL, version 1.4
11-30 15:21:54.719 2170-2210/rawpepper.it.digitalbox W/EGL_emulation: eglSurfaceAttrib not implemented
11-30 15:21:54.719 2170-2210/rawpepper.it.digitalbox W/OpenGLRenderer: Failed to set EGL_SWAP_BEHAVIOR on surface 0xad6fc2e0, error=EGL_SUCCESS
11-30 15:21:57.542 2170-2204/rawpepper.it.digitalbox D/Volley: [117] BasicNetwork.logSlowRequests: HTTP response for request=<[ ] http://digitalbox.getsandbox.com/item 0x95b78f5f NORMAL 1> [lifetime=3034], [size=196862], [rc=200], [retryCount=0]
11-30 15:21:57.691 2170-2180/rawpepper.it.digitalbox W/art: Suspending all threads took: 25.964ms
11-30 15:21:57.909 2170-2405/rawpepper.it.digitalbox D/sections: DB updated
告诉我sectionList数组中的元素数是13（第六行），这是正确的。 app run with Android Studio 如果我创建apk并将其安装在我的智能手机上，我将其插入PC以检查日志，当我运行应用程序时，我有这个日志
11-30 15:35:01.765 17183-17183/rawpepper.it.digitalbox I/art: Late-enabling -Xcheck:jni
11-30 15:35:01.883 17183-17183/rawpepper.it.digitalbox W/System: ClassLoader referenced unknown path: /data/app/rawpepper.it.digitalbox-2/lib/arm
11-30 15:35:02.357 17183-17183/rawpepper.it.digitalbox W/art: Before Android 4.1, method int android.support.v7.internal.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
11-30 15:35:03.235 17183-17183/rawpepper.it.digitalbox D/ELEMENT: 0
11-30 15:35:03.249 17183-17260/rawpepper.it.digitalbox D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
11-30 15:35:03.304 17183-17260/rawpepper.it.digitalbox I/Adreno-EGL: <qeglDrvAPI_eglInitialize:379>: QUALCOMM Build: 09/02/15, 76f806e, Ibddc658e36
11-30 15:35:03.306 17183-17260/rawpepper.it.digitalbox I/OpenGLRenderer: Initialized EGL, version 1.4
11-30 15:35:05.976 17183-17321/rawpepper.it.digitalbox D/sections: DB updated
告诉我sectionList数组中的元素是0，但如果我关闭并再次运行它，一切都是正确的。
答案 0 :(得分：0)
您需要在下载数据后设置抽屉。例如，在onCreate（）中下载新节和setUpDraw（）时调用saveDate（）。
private void saveData(Sections newSections) {
newSections.save()
setUpDraw()
}
private void setUpDraw() {
drawerListView = (ListView) findViewById(R.id.drawer_listView);
sectionsList = new RushSearch().whereEqual("Fk", 0).find(Sections.class);
drawerListViewAdapter = new DrawerListViewAdapter(sectionsList, context); // You don't want application context
drawerListView.setAdapter(drawerListViewAdapter);
drawerListView.setOnItemClickListener(click);
}
答案 1 :(得分：0)
我认为您应该将这部分内容称为代码：
Warning: React.createElement: type should not be null, undefined, boolean, or number. It should be a string (for DOM elements) or a ReactClass (for composite components). Check the render method of `exports`. react.js:20250
warning @ react.js:20728
ReactElementValidator.createElement @ react.js:9853
t.exports.React.createClass.render @ bundle.js:1ReactCompositeComponentMixin._renderValidatedComponentWithoutOwnerOrContext @ react.js:6330
ReactCompositeComponentMixin._renderValidatedComponent @ react.js:6350
wrapper @ react.js:12868
ReactCompositeComponentMixin._updateRenderedComponent @ react.js:6303
ReactCompositeComponentMixin._performComponentUpdate @ react.js:6287
ReactCompositeComponentMixin.updateComponent @ react.js:6216
wrapper @ react.js:12868
ReactCompositeComponentMixin.performUpdateIfNecessary @ react.js:6164
ReactReconciler.performUpdateIfNecessary @ react.js:13667
runBatchedUpdates @ react.js:15356
Mixin.perform @ react.js:17245
Mixin.perform @ react.js:17245
assign.perform @ react.js:15313
flushBatchedUpdates @ react.js:15374
wrapper @ react.js:12868
Mixin.closeAll @ react.js:17311
Mixin.perform @ react.js:17258
ReactDefaultBatchingStrategy.batchedUpdates @ react.js:8842
batchedUpdates @ react.js:15321
ReactEventListener.dispatchEvent @ react.js:10336
Uncaught Error: Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object. Check the render method of `exports`.
saveSections（）方法完成后。像这样：
var List = require("components/Forms/productList/view.jsx");}
答案 2 :(得分：0)
我修改了我的代码，现在我有了onCreate()方法的代码
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
callWebservice();
// setContentView(R.layout.activity_main);
// Layout principale col drawer
setContentView(R.layout.activity_main_drawer);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
leftArrow = (ImageView) findViewById(R.id.left_arrow);
titolo = (TextView) findViewById(R.id.titolo_id);
ActionBarDrawerToggle actionBarDrawerToggle =
new ActionBarDrawerToggle(this, drawerLayout, toolbar,
R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawerLayout.setDrawerListener(actionBarDrawerToggle);
actionBarDrawerToggle.syncState();
drawerListView = (ListView) findViewById(R.id.drawer_listView);
setupDrawer();
}
setupDrawer()方法
private void setupDrawer() {
// SELECT * FROM Sections where Fk == 0;
sectionsList = new RushSearch().whereEqual("Fk", 0).find(Sections.class);
Log.d("ELEMENT", "" + sectionsList.size());
drawerListViewAdapter = new DrawerListViewAdapter(sectionsList, getApplicationContext());
// Adapter che si occupa di popolare il drawer
drawerListView.setAdapter(drawerListViewAdapter);
// Listner per il click su un elemento del drawer
drawerListView.setOnItemClickListener(click);
}
如果我在{-1}}或onCreate()之后在try-catch中调用此方法，我会遇到同样的问题。
答案 3 :(得分：0)
private void callWebservice() {
String tag_json_obj = "GetItem";
String url = String.format("http://digitalbox.getsandbox.com/item");
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
new SaveData().execute(response.getJSONArray("Sections"));
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Settings", "Error: " + error.getMessage());
}
}) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> headers = new HashMap<String, String>();
headers.put("Content-Type", "application/json");
headers.put("Accept", "application/json");
return headers;
}
};
NetworkController.getInstance().addToRequestQueue(jsonObjectRequest, tag_json_obj);
}
然后在您的活动中添加此内部类：
private final class SaveData extends AsyncTask<JSONArray, Void, Void> {
protected Void doInBackground(JSONArray... params) {
int c = section.length();
for (int i = 0; i < c; i++) {
try {
JSONObject obj = section.getJSONObject(i);
Sections s = new RushSearch().whereEqual("ID", obj.getInt("ID")).findSingle(Sections.class);
if (s == null) {
s = new Sections();
s.setID(obj.getInt("ID"));
}
if (!obj.isNull("Fk"))
s.setFk(obj.getInt("Fk"));
s.setTitle(obj.getString("Title"));
if (!obj.isNull("CategoryColor"))
s.setCategoryColor(obj.getString("CategoryColor"));
s.setPos(obj.getInt("Pos"));
s.setLanguageId(obj.getInt("LanguageId"));
s.setUnavailableForSend(obj.getBoolean("UnavailableForSend"));
s.save();
} catch (JSONException e) {
e.printStackTrace();
}
}
Log.d("sections", "DB updated");
return null;
}
public void onPostExecute(Void result) {
sectionsList = new RushSearch().whereEqual("Fk", 0).find(Sections.class);
Log.d("ELEMENTI",""+sectionsList.size());
drawerListViewAdapter = new DrawerListViewAdapter(sectionsList, getApplicationContext());
}
}
我希望这有帮助！