我的应用程序目前包含 2 个活动。. 带有 Gallery View 的 MAIN 活动。带有 ListView 的 FriendsListActivity
当用户使用后退按钮离开 FriendsListActivity 并返回到 MAIN 活动时,以下错误在调试模式下不断弹出。
DalvikVM[localhost:8676] 线程 [<1> main] (Suspended (exception RuntimeException))
ActivityThread.performResumeActivity(IBinder, boolean) line: 2095
ActivityThread.handleResumeActivity(IBinder, boolean, boolean) line: 2110
BinderProxy(ActivityThread$H) .handleMessage(Message) 行:954 ActivityThread$H(Handler).dispatchMessage(Message) 行:99 Looper.loop() 行:123 ActivityThread.main(String[]) 行:3647 Method.invokeNative(Object, Object[] , Class, Class[], Class, int, boolean) line: not available [native method] Method.invoke(Object, Object...) line: 507
ZygoteInit$MethodAndArgsCaller.run() line: 839 ZygoteInit.main(String[]) line: 597 NativeStart.main(String[]) line: not available [native method] Thread [<8> Binder Thread #2] (Running)
线程 [<7> 活页夹线程 #1](正在运行)
使用 LogCat
03-13 22:01:10.972: 错误/AndroidRuntime(1038): 致命异常: main 03-13 22:01:10.972: 错误/AndroidRuntime(1038): java.lang.RuntimeException: 无法恢复活动 {com.package .MAIN/com.package.MAIN.MAIN}:java.lang.NullPointerException 03-13 22:01:10.972:错误/AndroidRuntime(1038):在 android.app.ActivityThread.performResumeActivity(ActivityThread.java:2095)03- 13 22:01:10.972: 错误/AndroidRuntime(1038): 在 android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2110) 03-13 22:01:10.972: 错误/AndroidRuntime(1038): 在 android.app。 ActivityThread$H.handleMessage(ActivityThread.java:954) 03-13 22:01:10.972: 错误/AndroidRuntime(1038): 在 android.os.Handler.dispatchMessage(Handler.java:99) 03-13 22:01: 10.972:错误/AndroidRuntime(1038):在 android.os.Looper。循环(Looper.java:123)03-13 22:01:10.972:错误/AndroidRuntime(1038):在 android.app.ActivityThread.main(ActivityThread.java:3647)03-13 22:01:10.972:错误/ AndroidRuntime(1038): at java.lang.reflect.Method.invokeNative(Native Method) 03-13 22:01:10.972: ERROR/AndroidRuntime(1038): at java.lang.reflect.Method.invoke(Method.java: 507) 03-13 22:01:10.972: 错误/AndroidRuntime(1038): 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 03-13 22:01:10.972: 错误/ AndroidRuntime(1038): 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 03-13 22:01:10.972: 错误/AndroidRuntime(1038): 在 dalvik.system.NativeStart.main(Native方法)03-13 22:01:10.972:错误/AndroidRuntime(1038):引起:java.lang.NullPointerException 03-13 22:01:10.972:错误/AndroidRuntime(1038): 在 com.package.MAIN.MAIN.onResume(MAIN.java:91) 03-13 22:01:10.972: 错误/AndroidRuntime(1038): 在 android.app.Instrumentation.callActivityOnResume(Instrumentation .java:1149) 03-13 22:01:10.972: 错误/AndroidRuntime(1038): 在 android.app.Activity.performResume(Activity.java:3833) 03-13 22:01:10.972: 错误/AndroidRuntime(1038) ): 在 android.app.ActivityThread.performResumeActivity(ActivityThread.java:2085) 03-13 22:01:10.972: ERROR/AndroidRuntime(1038): ... 10 更多performResume(Activity.java:3833) 03-13 22:01:10.972: ERROR/AndroidRuntime(1038): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2085) 03-13 22:01:10.972: ERROR/ AndroidRuntime(1038): ... 10 更多performResume(Activity.java:3833) 03-13 22:01:10.972: ERROR/AndroidRuntime(1038): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2085) 03-13 22:01:10.972: ERROR/ AndroidRuntime(1038): ... 10 更多
变量面板中的更多信息说明:
this: ActivityThread
e: NullPointerException
cause: NullPointerException
detailMessage: null
stackTrace: null
r: ActivityThread$ActivityClientRecord
activity: MAIN
一次 Eclipse 恢复后的 detailMessage:无法恢复活动(主要)
FriendsListActivity 中的代码如下所示
public class FriendsListActivity extends ListActivity {
// ===========================================================
// Fields
// ===========================================================
private ArrayList<Friend> friends = new ArrayList<Friend>();
private FriendsArrayAdapter friendsArrayAdapter;
private ListView listView;
// ===========================================================
// onCreate
// ===========================================================
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.friends_list);
registerForContextMenu(getListView());
setButtonNewFriendClickListener();
}
public void generateFriendsList() {
FriendsService fs = new FriendsService(this);
friends = fs.getFriendsList();
listView = (ListView) findViewById(android.R.id.list);
friendsArrayAdapter = new FriendsArrayAdapter(
this, R.layout.friend_list_item, friends);
listView.setAdapter(friendsArrayAdapter);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.friends_context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
FriendsService fs = new FriendsService(this);
Friend f = new Friend();
f = friends.get(info.position);
switch (item.getItemId()) {
case R.id.edit:
Intent i = new Intent(this, FriendEditActivity.class);
i.putExtra("userid", f.userId);
startActivity(i);
return true;
case R.id.delete:
fs.deleteFriend(f.userId);
generateFriendsList();
return true;
default:
return super.onContextItemSelected(item);
}
}
// ===========================================================
// onPause
// ===========================================================
protected void onPause() {
super.onPause();
finish();
}
// ===========================================================
// onResume
// ===========================================================
protected void onResume() {
super.onResume();
generateFriendsList();
}
// ===========================================================
// onStop
// ===========================================================
protected void onStop() {
super.onStop();
}
// ===========================================================
// onDestroy
// ===========================================================
@Override
protected void onDestroy() {
super.onDestroy();
}
// ===========================================================
// Activity methods
// ===========================================================
private void setButtonNewFriendClickListener() {
Button clickButton = (Button)findViewById(R.id.button_add_friend);
clickButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent i = new Intent(v.getContext(), FriendNewActivity.class);
startActivity(i);
}
});
}
AndroidManifest 看起来像这样
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
android:versionCode="1"
android:versionName="1.0" package="com.package.mypackage">
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name="com.package.mypackage.mypackage"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".FriendsListActivity"></activity>
<activity android:name=".FriendEditActivity"></activity>
<activity android:name=".FriendNewActivity"></activity>
<activity android:name=".TakePictureActivity"></activity>
<activity android:name=".FriendsService"></activity>
<activity android:name=".MyService"></activity>
</application>
<uses-sdk android:minSdkVersion="9" />
MAIN 活动如下所示:
package com.package.mypackage;
import java.util.ArrayList;
import com.package.domain.Domain;
import com.package.service.MyService;
import com.package.viewadapter.myImageAdapter;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.Button;
import android.widget.Gallery;
import android.widget.Toast;
public class myActivity extends Activity {
// ===========================================================
// Fields
// ===========================================================
private MyImageAdapter myImageAdapter;
private ArrayList<Domain> domain = new ArrayList<Domain>();
// ===========================================================
// onCreate
// ===========================================================
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
/* Set Buttons to listen for any click event. */
setButtonFriendsClickListener();
setButtonCameraClickListener();
setButtonPreferencesClickListener();
}
// ===========================================================
// onStart
// ===========================================================
@Override
public void onStart() {
super.onStart();
/* Find the gallery defined in the main.xml */
Gallery g = (Gallery) findViewById(R.id.gallery);
/* Show a Toast message when image is clicked */
g.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
MyImageAdapter image_ID = new MyImageAdapter(myActivity.this, position, null);
if (image_ID.getItemId(position) == 0) {
Toast test_toast = Toast.makeText(myActivity.this, "This is the New Image click", Toast.LENGTH_SHORT);
test_toast.show();
}
else {
Toast test_toast = Toast.makeText(myActivity.this, "The clicked image has image number " + image_ID.getItemId(position) + " in the imageadapter.", Toast.LENGTH_SHORT);
test_toast.show();
}
}
});
g.setOnItemLongClickListener(new OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View v, int position, long id) {
MyImageAdapter image_ID = new MyImageAdapter(myActivity.this, position, null);
Toast test_toast = Toast.makeText(myActivity.this, "The long clicked image has image number " + image_ID.getItemId(position) + " in the imageadapter.", Toast.LENGTH_SHORT);
test_toast.show();
return true;
}
});
}
// ===========================================================
// onPause
// ===========================================================
protected void onPause() {
super.onPause();
}
// ===========================================================
// onResume
// ===========================================================
protected void onResume() {
super.onResume();
generateMyGallery();
}
// ===========================================================
// onStop
// ===========================================================
protected void onStop() {
super.onStop();
}
// ===========================================================
// onDestroy
// Is also called when user changes from horizontal
// to vertical orientation and back
// ===========================================================
@Override
protected void onDestroy() {
super.onDestroy();
}
// ===========================================================
// Save and Restore UI states
// ===========================================================
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
}
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
}
// ===========================================================
// Main Activity methods
// ===========================================================
public void generateMyGallery() {
MyService cs = new MyService(this);
domain = cs.getDomainList();
// Add the new_image drawable to the ArrayList
Domain d = new Domain();
d.photoLocation = "drawable";
d.photoName = "new_image";
d.extra1 = "no_text";
d.extra2 = "no_text";
domain.add(0, d);
myImageAdapter = new MyImageAdapter(this, R.layout.text_overlay_image_view, domain);
/* Find the gallery defined in the main.xml */
Gallery g = (Gallery) findViewById(R.id.gallery);
g.setSpacing(10);
/* Apply a new (custom) ImageAdapter to it. */
g.setAdapter(myImageAdapter);
g.setSelection(1);
}
private void setButtonFriendsClickListener() {
Button clickButton = (Button)findViewById(R.id.button_friends_list);
clickButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
setContentView(R.layout.friends_list);
Intent myIntent = new Intent(v.getContext(), FriendsListActivity.class);
startActivity(myIntent);
}
});
}
private void setButtonCameraClickListener() {
Button clickButton = (Button)findViewById(R.id.button_take_picture);
clickButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
setContentView(R.layout.take_picture);
Intent myIntent = new Intent(v.getContext(), TakePictureActivity.class);
startActivity(myIntent);
}
});
}
private void setButtonPreferencesClickListener() {
Button clickButton = (Button)findViewById(R.id.button_preferences);
clickButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent myIntent = new Intent(v.getContext(), MyPreferencesActivity.class);
startActivity(myIntent);
}
});
}
};
任何人都知道应用程序崩溃的原因。任何帮助深表感谢。
我确实发现,当我在启动 FriendListActivity 时完成() MAIN 活动并在关闭 FriendListActivity 时重新启动 MAIN 活动时,不会发生崩溃。但是,这基本上会重新启动应用程序,这不是本意。
谢谢大家,我的问题解决了。这就是我所做的。
. 将所有与画廊相关的操作移动到 onCreate 时,不再发生崩溃。但是在返回 MAIN 活动后,该活动没有显示。
. 然后,我将所有 onCreate(除了 super)、generateGallery 和 onStart() 移动到 onResume。现在它工作正常!