调用 onResponse 时应用程序崩溃
App crashes when onResponse is called
我正在使用 volley 加载 JSON 数据。
这是 MainActivity
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private final String TAG = "MainActivity";
//Creating a list of posts
private List<PostItems> mPostItemsList;
//Creating Views
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "Device rotated and onCreate called");
//Initializing Views
recyclerView = (RecyclerView) findViewById(R.id.post_recycler);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
//Initializing the postlist
mPostItemsList = new ArrayList<>();
adapter = new PostAdapter(mPostItemsList, this);
recyclerView.setAdapter(adapter);
if (NetworkCheck.isAvailableAndConnected(this)) {
//Caling method to get data
getData();
} else {
final Context mContext;
mContext = this;
final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
alertDialogBuilder.setTitle("No Internet Connection");
alertDialogBuilder.setMessage("Failed to load. Please ensure you're connected to the internet and try again.");
alertDialogBuilder.setPositiveButton("Retry", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
if (!NetworkCheck.isAvailableAndConnected(mContext)) {
alertDialogBuilder.show();
} else {
getData();
}
}
});
alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
alertDialogBuilder.show();
}
}
//This method will get data from the web api
private void getData(){
Log.d(TAG, "getData called");
//Showing progress dialog
final ProgressDialog progressDialog = ProgressDialog.show(this, null, "Loading posts", false, false);
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigPost.GET_URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
progressDialog.dismiss();
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
}
如果应用程序启动并且我没有旋转它，它会加载并解析 JSON 非常好；但是如果应用程序启动并且我多次旋转设备，应用程序会在调用 onResponse 后立即崩溃。
这是堆栈跟踪
04-03 12:46:10.493 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:10.493 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:11.234 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:11.234 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:12.675 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:12.685 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:14.096 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:14.096 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:15.278 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:15.288 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:15.448 22221-22221/com.example.poster D/MainActivity: onResponse called
04-03 12:46:15.448 22221-22221/com.example.poster E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.poster, PID: 22221
java.lang.IllegalArgumentException: View=com.android.internal.policy.impl.PhoneWindow$DecorView{7873bab V.E..... R......D 0,0-480,174} not attached to window manager
at android.view.WindowManagerGlobal.findViewLocked(WindowManagerGlobal.java:396)
at android.view.WindowManagerGlobal.removeView(WindowManagerGlobal.java:322)
at android.view.WindowManagerImpl.removeViewImmediate(WindowManagerImpl.java:116)
at android.app.Dialog.dismissDialog(Dialog.java:341)
at android.app.Dialog.dismiss(Dialog.java:324)
at com.example.poster.MainActivity.onResponse(MainActivity.java:142)
at com.example.poster.MainActivity.onResponse(MainActivity.java:137)
at com.android.volley.toolbox.JsonRequest.deliverResponse(JsonRequest.java:65)
at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5910)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
从堆栈跟踪来看，第 142 行是 progressDialog.dismiss();，第 137 行是 new Response.Listener<JSONArray>() {
知道是什么原因造成的吗？
更新：我正在考虑对其进行编码，以便仅在首次创建应用程序时调用 getData()。这是因为，在配置更改（在本例中为旋转）后重新创建 activity 时，将调用 getData()。所以这会导致 activity 重新加载。这可能吗？ IE。仅在第一次调用 getData() 时，会创建 activity。
您只需要在关闭 progressdialog 时检查对象 null。
ProgressDialog progressDialog = ProgressDialog.show(this, null, "Loading posts", false, false);
if(progressDialog!=null)
progressDialog.dismiss();
当应用旋转时，activity 被重新创建。现在你已经得到了 ProgressDialog progressDialog 的实例。所以当 activity 旋转时，旧的 activity 被销毁，因此这个实例 progressDialog 被销毁。
现在，任务在后台线程上 运行，当它 returns 时，它找不到 progressDialog，因为它已被销毁，因此当前 not attached to window manager(IllegalArgumentException).
所以最好在访问实例 progressDialog 之前检查它 onResponse。
尝试像这样使用 ProgressDialog：
定义一个全局实例：
private ProgressDialog progressDialog;
在getData方法中：
private void getData(){
Log.d(TAG, "getData called");
//Showing progress dialog
progressDialog = new ProgressDialog(MainActivity.this);
progressDialog.setMessage("Loading posts");
progressDialog.show();
在onResponse回调中：
if(progressDialog!=null){
progressDialog.hide();
}
onDestroy 共 activity:
if(progressDialog!=null) progressDialog.dismiss(); // to prevent memory leak
我正在使用 volley 加载 JSON 数据。
这是 MainActivity
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private final String TAG = "MainActivity";
//Creating a list of posts
private List<PostItems> mPostItemsList;
//Creating Views
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "Device rotated and onCreate called");
//Initializing Views
recyclerView = (RecyclerView) findViewById(R.id.post_recycler);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
//Initializing the postlist
mPostItemsList = new ArrayList<>();
adapter = new PostAdapter(mPostItemsList, this);
recyclerView.setAdapter(adapter);
if (NetworkCheck.isAvailableAndConnected(this)) {
//Caling method to get data
getData();
} else {
final Context mContext;
mContext = this;
final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
alertDialogBuilder.setTitle("No Internet Connection");
alertDialogBuilder.setMessage("Failed to load. Please ensure you're connected to the internet and try again.");
alertDialogBuilder.setPositiveButton("Retry", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
if (!NetworkCheck.isAvailableAndConnected(mContext)) {
alertDialogBuilder.show();
} else {
getData();
}
}
});
alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
alertDialogBuilder.show();
}
}
//This method will get data from the web api
private void getData(){
Log.d(TAG, "getData called");
//Showing progress dialog
final ProgressDialog progressDialog = ProgressDialog.show(this, null, "Loading posts", false, false);
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigPost.GET_URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
progressDialog.dismiss();
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
}
如果应用程序启动并且我没有旋转它，它会加载并解析 JSON 非常好；但是如果应用程序启动并且我多次旋转设备，应用程序会在调用 onResponse 后立即崩溃。
这是堆栈跟踪
04-03 12:46:10.493 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:10.493 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:11.234 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:11.234 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:12.675 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:12.685 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:14.096 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:14.096 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:15.278 22221-22221/com.example.poster D/MainActivity: Device rotated and onCreate called
04-03 12:46:15.288 22221-22221/com.example.poster D/MainActivity: getData called
04-03 12:46:15.448 22221-22221/com.example.poster D/MainActivity: onResponse called
04-03 12:46:15.448 22221-22221/com.example.poster E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.poster, PID: 22221
java.lang.IllegalArgumentException: View=com.android.internal.policy.impl.PhoneWindow$DecorView{7873bab V.E..... R......D 0,0-480,174} not attached to window manager
at android.view.WindowManagerGlobal.findViewLocked(WindowManagerGlobal.java:396)
at android.view.WindowManagerGlobal.removeView(WindowManagerGlobal.java:322)
at android.view.WindowManagerImpl.removeViewImmediate(WindowManagerImpl.java:116)
at android.app.Dialog.dismissDialog(Dialog.java:341)
at android.app.Dialog.dismiss(Dialog.java:324)
at com.example.poster.MainActivity.onResponse(MainActivity.java:142)
at com.example.poster.MainActivity.onResponse(MainActivity.java:137)
at com.android.volley.toolbox.JsonRequest.deliverResponse(JsonRequest.java:65)
at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5910)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
从堆栈跟踪来看，第 142 行是 progressDialog.dismiss();，第 137 行是 new Response.Listener<JSONArray>() {
知道是什么原因造成的吗？
更新：我正在考虑对其进行编码，以便仅在首次创建应用程序时调用 getData()。这是因为，在配置更改（在本例中为旋转）后重新创建 activity 时，将调用 getData()。所以这会导致 activity 重新加载。这可能吗？ IE。仅在第一次调用 getData() 时，会创建 activity。
您只需要在关闭 progressdialog 时检查对象 null。
ProgressDialog progressDialog = ProgressDialog.show(this, null, "Loading posts", false, false);
if(progressDialog!=null)
progressDialog.dismiss();
当应用旋转时，activity 被重新创建。现在你已经得到了 ProgressDialog progressDialog 的实例。所以当 activity 旋转时，旧的 activity 被销毁，因此这个实例 progressDialog 被销毁。
现在，任务在后台线程上 运行，当它 returns 时，它找不到 progressDialog，因为它已被销毁，因此当前 not attached to window manager(IllegalArgumentException).
所以最好在访问实例 progressDialog 之前检查它 onResponse。
尝试像这样使用 ProgressDialog：
定义一个全局实例：
private ProgressDialog progressDialog;
在getData方法中：
private void getData(){
Log.d(TAG, "getData called");
//Showing progress dialog
progressDialog = new ProgressDialog(MainActivity.this);
progressDialog.setMessage("Loading posts");
progressDialog.show();
在onResponse回调中：
if(progressDialog!=null){
progressDialog.hide();
}
onDestroy 共 activity:
if(progressDialog!=null) progressDialog.dismiss(); // to prevent memory leak