SimpleAdapter 每隔一秒启动一次就崩溃一次

Posted 2023-05-07

【中文标题】SimpleAdapter 每隔一秒启动一次就崩溃一次

【英文标题】：SimpleAdapter crashes every second launch time

【发布时间】：2017-06-20 00:43:21

【问题描述】：

我有一个 SimpleAdapter 过滤 inputSearch 和可点击的项目（我从 mysql 数据库中获得）。

有时在我的项目午餐时出现错误：

java.lang.RuntimeException: Unable to start activity ComponentInfocom.brzozowski.marcin.inzynierka/com.brzozowski.marcin.inzynierka.activities.ChooseGroupActivity: java.lang.NullPointerException: Attempt to invoke virtual method 'android.widget.Filter android.widget.SimpleAdapter.getFilter()' on a null object reference
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
                  at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947)
                  at android.app.ActivityThread.access$900(ActivityThread.java:151)
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1309)
                  at android.os.Handler.dispatchMessage(Handler.java:102)
                  at android.os.Looper.loop(Looper.java:135)
                  at android.app.ActivityThread.main(ActivityThread.java:5254)
                  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:903)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
               Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.widget.Filter android.widget.SimpleAdapter.getFilter()' on a null object reference
                  at com.brzozowski.marcin.inzynierka.activities.ChooseGroupActivity$2.onTextChanged(ChooseGroupActivity.java:103)
                  at android.widget.TextView.sendOnTextChanged(TextView.java:7679)
                  at android.widget.TextView.setText(TextView.java:4060)
                  at android.widget.TextView.setText(TextView.java:3915)
                  at android.widget.EditText.setText(EditText.java:85)
                  at android.widget.TextView.setText(TextView.java:3890)
                  at android.widget.TextView.onRestoreInstanceState(TextView.java:3790)
                  at android.view.View.dispatchRestoreInstanceState(View.java:13740)
                  at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2893)
                  at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2893)
                  at android.view.View.restoreHierarchyState(View.java:13718)
                  at com.android.internal.policy.impl.PhoneWindow.restoreHierarchyState(PhoneWindow.java:2009)
                  at android.app.Activity.onRestoreInstanceState(Activity.java:1023)
                  at android.app.ListActivity.onRestoreInstanceState(ListActivity.java:219)
                  at android.app.Activity.performRestoreInstanceState(Activity.java:978)
                  at android.app.Instrumentation.callActivityOnRestoreInstanceState(Instrumentation.java:1162)
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
                  at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947) 
                  at android.app.ActivityThread.access$900(ActivityThread.java:151) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1309) 
                  at android.os.Handler.dispatchMessage(Handler.java:102) 
                  at android.os.Looper.loop(Looper.java:135) 
                  at android.app.ActivityThread.main(ActivityThread.java:5254) 
                  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:903) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

当我下次启动应用程序时，一切正常。 所以错误发生在每第二次启动。

【问题讨论】：

可以输入你的ChooseGroupActivity的代码吗？

我添加了代码。

【参考方案1】：

从 onResume 中移除 simpleAdapter 初始化。 在你的 onCreate 中

@Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        initAdapter();


private void initAdapter()
        simpleAdapter = new SimpleAdapter(this, employeeList,
        android.R.layout.simple_list_item_1,
        new String[]  "groups" , new int[]  android.R.id.text1 );
        listView.setAdapter(simpleAdapter);

@Override
public void onTextChanged(CharSequence s, int start, int before, int count)  
 if(simpleAdapter == null)
    initAdapter();

simpleAdapter.getFilter().filter(s);
       

【参考方案2】：

您在onResume 中创建了SimpleAdapter，但这里发生的是您在onCreate 中设置了textChangedListener。调用onCreate 后，Android 会恢复视图状态，包括视图中的文本。这会在 onResume 运行之前触发文本更改侦听器并创建 SimpleAdapter。我认为你可以将SimpleAdapter 设置移动到onCreate，然后它应该就可以工作了。