Android解决：The content of the adapter has changed but ListView did not receive a notification

(Updated: )
android

项目中的错误，记录一下。

完整的错误信息如下：

1
The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread. [in ListView(2131492991, class android.widget.ListView) with Adapter(class com.impulsefitness.support.ui.WorkOrderDetailActivity$CustomFeedbackListViewAdapter)]

大意是说adapter内容已改变，但listview未收到通知，上下文不同步了。

精简一下，我有两个ActivityA和ActivityB。首先打开ActivityA，显示一个列表（listView），然后点击一个按钮startActivityForResult打开了B，B中添加了信息提交后setResult到A。B负责添加数据，添加完数据回到A，通知A重新load一遍远端数据，没问题（不要问我为什么要重新load一遍）。

在Activity A中单独起了一个线程去处理任务（请求远端service获取数据），handler收到message之后启动这个线程t，然后Activity A又startActivityForResult了另一个Activity B（这时候ActivityA已经onPause了，但是线程依然在运行，而且还在handler的callback队列中），当Activity B处理完逻辑setResult给Activity A（并且把自己给finish掉），需要让ActivityA重新请求service数据，也就是说线程t要重新运行一次，这时候handler里面已经有线程t这个对象了，然后就导致了上述的错误（好像这么说很牵强啊），参照CSDN牛人的文章，还是线程与上下文的事。

解决办法，在ActivityA的onPause将线程t从handler的callback中移除（然后handler再次收到同样的请求service的message时会重新将此线程t加入到callback队列中），如下：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
@Override
    protected void onPause() {
        super.onPause();
        handler.removeCallbacks(tListFeedback);
    }
Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);

            switch (msg.what) {
                //页面加载，loading显示
                case 0x00:
                    pbFeedback.setVisibility(View.VISIBLE);
                    Message.obtain(this, 0x01, msg.obj).sendToTarget();
                    break;
                //请求service，用于获取反馈列表数据
                case 0x01:
                    tListFeedback = new ThreadListFeedback(msg.obj.toString());
                    ThreadPoolUtils.execute(tListFeedback);
                    break;

ActivityA的完整代码如下：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
super.findViewById(R.id.tvContactAddress);
        tvComment2 = (TextView) super.findViewById(R.id.tvComment2);
        tvPartIdNm = (TextView) super.findViewById(R.id.tvPartIdNm);
        tvPartAmount = (TextView) super.findViewById(R.id.tvPartAmount);
        tvPartFee = (TextView) super.findViewById(R.id.tvPartFee);
        tvCustomerName = (TextView) super.findViewById(R.id.tvCustomerName);
        tvMobile = (TextView) super.findViewById(R.id.tvMobile);
        tvContactName = (TextView) super.findViewById(R.id.tvContactName);
        tvContactMobile = (TextView) super.findViewById(R.id.tvContactMobile);
        ivCall1 = (ImageView) super.findViewById(R.id.ivCall1);
        ivCall2 = (ImageView) super.findViewById(R.id.ivCall2);
        lvFeedback = (ListView) super.findViewById(R.id.lvFeedback);
        pbFeedback = (ProgressBar) super.findViewById(R.id.pbFeedback);

        customAdapter = new CustomFeedbackListViewAdapter(activity);
        lvFeedback.setEmptyView(super.findViewById(R.id.llListViewNoItemFeedbackDetail));
        lvFeedback.setAdapter(customAdapter);

        AddFeedbackListener feedbackListener = new AddFeedbackListener();
        btnAddFeedback.setOnClickListener(feedbackListener);

        FinishListener finishListener = new FinishListener();
        ivBack.setOnClickListener(finishListener);
        llIvBack.setOnClickListener(finishListener);

        tvTitle.setText(this.getResources().getText(R.string.activity_name_workorder_detail));

        Intent i = getIntent();
        Bundle b = i.getExtras();
        if (null == b) {
            tost(R.string.activity_workorder_detail_invalid_workorderno);
            this.finish();
        } else {
            String workOrderNo = b.getString("workorderno");
            if (null == workOrderNo) {
                tost(R.string.activity_workorder_detail_invalid_workorderno);
                this.finish();
            } else {

                Message.obtain(handler, 0x00, workOrderNo).sendToTarget();      //通知handler，开始load数据

                tvWorkOrderNo.setText(workOrderNo);
                tvServiceType.setText(b.getString("serviceType"));
                tvBookingTime.setText(b.getString("bookingTime"));
                tvContactAddress.setText(b.getString("constructAddress"));
                tvComment2.setText(b.getString("comment2"));
                tvPartIdNm.setText(b.getString("partId") + b.getString("partName"));
                tvPartAmount.setText(b.getString("partAmount") + "台");
                tvPartFee.setText(b.getString("partFee"));
                tvCustomerName.setText(b.getString("customerName"));
                tvMobile.setText(b.getString("mobile"));
                tvContactName.setText(b.getString("contactName"));
                tvContactMobile.setText(b.getString("contactMobile"));

                ivCall1.setOnClickListener(new CallListener(tvMobile.getText().toString()));
                ivCall2.setOnClickListener(new CallListener(tvContactMobile.getText().toString()));
            }
        }
    }

    /**
     * 自定义ListView Adapter
     */
    class CustomFeedbackListViewAdapter extends BaseAdapter {

        //对象所在的上下文Activity
        Activity activity;

        public CustomFeedbackListViewAdapter(Activity activity) {
            this.activity = activity;
        }

        @Override
        public int getCount() {
            return listViewData.size();
        }

        @Override
        public Object getItem(int position) {
            return listViewData.get(position);
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        class ViewHolder {
            TextView tvFeedbackContent;
            ImageView ivArrowLaunch;
        }

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {

            ViewHolder holder;
            LayoutInflater inflater = activity.getLayoutInflater();

            if (convertView == null) {
                convertView = inflater.inflate(R.layout.listview_feedback_detail_item, null);
                holder = new ViewHolder();

            } else {
                holder = (ViewHolder) convertView.getTag();
                if (null == holder)
                    holder = new ViewHolder();
            }

            holder.tvFeedbackContent = (TextView) convertView.findViewById(R.id.tvFeedbackContentCombineStatement);
            holder.ivArrowLaunch = (ImageView) convertView.findViewById(R.id.ivFeedbackContentArrowLaunch);

            holder.ivArrowLaunch.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    tost(R.string.btn_txt_ok);
                }
            });

            HashMap<String, Object> map = listViewData.get(position);
            holder.tvFeedbackContent.setText(
                    map.get("employeeName").toString() + "在" + map.get("isrtDt") + "添加了反馈\"" + map.get("feedbackContent") + "\""
            );

            return convertView;
        }
    }

    ThreadListFeedback tListFeedback;
    /**
     * 消息处理handler
     */
    Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);

            switch (msg.what) {
                //页面加载，loading显示
                case 0x00:
                    pbFeedback.setVisibility(View.VISIBLE);
                    Message.obtain(this, 0x01, msg.obj).sendToTarget();
                    break;
                //请求service，用于获取反馈列表数据
                case 0x01:
                    tListFeedback = new ThreadListFeedback(msg.obj.toString());
                    ThreadPoolUtils.execute(tListFeedback);
                    break;
                //请求成功，已获取到数据
                case 0x02:
                    pbFeedback.setVisibility(View.GONE);
                    Bundle b = msg.getData();
                    if (null != b)
                        try {
                            SaxJson(b.get("remoteInfo"));
                        } catch (JSONException e) {
                            e.printStackTrace();
                            Message.obtain(this, -0x03, e.getMessage()).sendToTarget();
                        }
                    else
                        Message.obtain(this, -0x03, ":" + getString(activity, R.string.not_acquired_data)).sendToTarget();
                    break;
                //请求失败
                case -0x02:
                    pbFeedback.setVisibility(View.GONE);
                    String m = getString(activity, R.string.not_acquired_data) + msg.obj;
                    tost(m);
                    break;
                //解析json串异常
                case -0x03:
                    tost("parse error" + msg.obj);
                    break;
                //解析json正常，刷新UI
                case 0x04:
                    customAdapter.notifyDataSetChanged();
                    Message.obtain(this, 0x05).sendToTarget();
                    break;
                case 0x05:
                    setListViewHeight(lvFeedback);
                    break;
            }
        }
    };

    @Override
    protected void onPause() {
        super.onPause();
        handler.removeCallbacks(tListFeedback);
    }

    /**
     * 请求service获取反馈列表Runnable对象
     */
    class ThreadListFeedback extends Thread {

        String workOrderNo;

        public ThreadListFeedback(String workOrderNo) {
            this.workOrderNo = workOrderNo;
        }

        @Override
        public void run() {
            Map<String, Object> requestData = new HashMap<>();
            Bundle bundle = new Bundle();
            try {
                requestData.put("workOrderNo", workOrderNo);

                SoapInfo soapInfo = ServiceConstant.getWorkOrderFeedbackList();
                soapInfo.setRequestData(requestData);

                SoapService soapService = new SoapService(soapInfo);
                String remoteInfo = soapService.getRemoteInfo();
                bundle.putString("remoteInfo", remoteInfo);

                if (remoteInfo == "-1")
                    Message.obtain(handler, -0x02, getString(activity, R.string.activity_workorder_detail_invalid_workorderno)).sendToTarget();
                else {
                    Message m = Message.obtain(handler, 0x02);
                    m.setData(bundle);
                    m.sendToTarget();
                }

                Log.i(MainActivity.TAG, "remoteInfo:" + remoteInfo);

            } catch (Exception e) {
                e.printStackTrace();
                Message.obtain(handler, -0x02, e.getMessage()).sendToTarget();
            }
        }
    }

    /**
     * 解析service返回json串
     *
     * @param objJson
     */
    void SaxJson(Object objJson) throws JSONException {
        JSONArray jsonArray = new JSONArray(objJson.toString());

        for (int i = 0; i < jsonArray.length(); i++) {
            JSONObject jsonObject = (JSONObject) jsonArray.get(i);
            HashMap<String, Object> item = new HashMap<>();

            item.put("feedbackId", jsonObject.getString("feedbackId").trim());
            item.put("workOrderNo", jsonObject.getString("workOrderNo").trim());
            item.put("repairEmployeeId", jsonObject.getString("repairEmployeeId").trim());
            item.put("employeeName", jsonObject.getString("employeeName").trim());

            item.put("contactName", jsonObject.getString("contactName").trim());
            item.put("contactPhone", jsonObject.getString("contactPhone").trim());
            item.put("contactMobile", jsonObject.getString("contactMobile").trim());
            item.put("contactTime", jsonObject.getString("contactTime").trim());
            item.put("feedbackContent", jsonObject.getString("feedbackContent").trim());
            item.put("isrtDt", SimpleUtils.DateTimeUtils.parseTime("yyyy-MM-dd", jsonObject.getString("isrtDt").trim()));

            listViewData.add(item);
        }

        Message.obtain(handler, 0x04).sendToTarget();
    }

    /**
     * 添加反馈按钮事件监听器
     */
    class AddFeedbackListener implements View.OnClickListener {
        @Override
        public void onClick(View v) {

            Intent i = getIntent();
            i.putExtra("workorderno", tvWorkOrderNo.getText());
            i.setClass(WorkOrderDetailActivity.this, WorkOrderFeedbackActivity.class);
            startActivityForResult(i, 0x00);
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch (requestCode) {
            case 0x00:
                //添加反馈完成，刷新数据
                if (null != data) {
                    boolean submitted = data.getBooleanExtra("submitted", false);
                    if (submitted)
                        Message.obtain(handler, 0x00, data.getStringExtra("workOrderNo")).sendToTarget();      //通知handler，开始load数据
                }
                break;
        }
    }

    /**
     * 关闭当前Activity单击事件监听器
     */
    class FinishListener implements View.OnClickListener {
        @Override
        public void onClick(View v) {
            WorkOrderDetailActivity.this.finish();
        }
    }

    /**
     * Call监听器
     */
    class CallListener implements View.OnClickListener {
        String telNo;

        public CallListener(String telNo) {
            this.telNo = telNo;
        }

        @Override
        public void onClick(View v) {
            Intent intent = new Intent(Intent.ACTION_DIAL, Uri.parse("tel://" + telNo));
            startActivity(intent);
        }
    }

    /**
     * 自定义actionBar布局文件
     * http://www.cnblogs.com/yc-755909659/p/4290784.html
     *
     * @param layoutId
     */

    void setActionBarLayout(int layoutId) {

        if (null != actionBar) {
            actionBar.setDisplayShowHomeEnabled(false);
            actionBar.setDisplayShowCustomEnabled(true);
            actionBar.setDisplayShowTitleEnabled(false);
            LayoutInflater inflator = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View v = inflator.inflate(layoutId, null);
            ActionBar.LayoutParams layout = new ActionBar.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
            actionBar.setCustomView(v, layout);
        }
    }
}

新解：

还是上面的错误信息，注意这句：

1
Make sure the content of your adapter is not modified from a background thread, but only from the UI thread.

确保adapter的内容不要在后台线程中修改，只能从UI线程中修改。而我的代码是直接message交给handler去处理的，难道这也算后台线程？于是想到了Runnable对象，它是依附于UI线程的，然后使用了handler.post(new Runnable())的方法，测试成功。