小编Ami*_*r_P的帖子

我想用这段代码在画布上绘制一个 drawable 但它不起作用，我不知道为什么

getResources().getDrawable(R.drawable.allergist).draw(canvas);

我将自定义视图的高度和宽度设置为与父视图匹配，但整个屏幕是白色的，屏幕上没有可绘制的

我正在尝试以android.support.v7.widget.SwitchCompat编程方式添加,我收到此错误:

java.lang.NullPointerException: Attempt to invoke interface method 'int java.lang.CharSequence.length()' on a null object reference
at android.text.StaticLayout.<init>(StaticLayout.java:422)
at android.support.v7.widget.SwitchCompat.makeLayout(SwitchCompat.java:602)
at android.support.v7.widget.SwitchCompat.onMeasure(SwitchCompat.java:526)
at android.view.View.measure(View.java:18799)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1458)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:746)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:629)
at android.view.View.measure(View.java:18799)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1458)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:746)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:629)
at android.view.View.measure(View.java:18799)
at android.support.v7.widget.Toolbar.measureChildCollapseMargins(Toolbar.java:1218)
at android.support.v7.widget.Toolbar.onMeasure(Toolbar.java:1326)
at android.view.View.measure(View.java:18799)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1458)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:746)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:629)
at android.support.design.widget.AppBarLayout.onMeasure(AppBarLayout.java:199)
at android.view.View.measure(View.java:18799)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:668)
at android.support.design.widget.AppBarLayout$Behavior.onMeasureChild(AppBarLayout.java:888)
at android.support.design.widget.AppBarLayout$Behavior.onMeasureChild(AppBarLayout.java:652)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:733)
at android.view.View.measure(View.java:18799)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5951)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135) …

  ATNRef= FirebaseDatabase.getInstance().getReference("AvailableTokenNumber");
                ATNRef.runTransaction(new Transaction.Handler() {
                    @Override
                    public Transaction.Result doTransaction(MutableData mutableData) {

                        if (mutableData.getValue(int.class ) == 0){
                            mutableData.setValue(2);
                            data.tokenNo = 1;
                            return Transaction.success(mutableData);

                        }else {
                            data.tokenNo=mutableData.getValue(int.class);
                            mutableData.setValue(data.tokenNo + 1);
                            return Transaction.success(mutableData);
                        }
                    }

每当代码第一次运行时，data.tokenNo的值均为0。之后，它将根据数据库值正确更新。

我无法弄清楚是什么使每次应用程序/代码的首次运行时data.token = 0的值。

我在UICollectionView使用iOS11模拟器时遇到了一个奇怪的问题.在项目中,我有一个UICollectionView与UIImageView细胞和我已经通过拖动到视图控制器创建赛格瑞作为触发塞格斯的细胞.它工作得很好但是知道segue没有执行所以我决定从单元格中删除segue Triggered Segues并且我从视图控制器创建了一个segue到目标视图控制器并从代码执行segue

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "PhotoCell", for: indexPath) as! PhotoCell
    if let url = URL(string: "\(StringResources.serverAddress)/Content/images/Files/Thumb/\(photos[indexPath.row])") {
        cell.image.downloadFrom(url: url)
    }
    return cell
}

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    print("clicked")
    performSegue(withIdentifier: "PhotoSegue", sender: collectionView.cellForItem(at: indexPath))
}

但它也没有工作,并且在控制台中没有点击打印.我已检查过单元格和UIImageView用户交互,UICollectionView委托也没问题.我该如何解决？

编辑:我发现了问题.当我双击单元格时,它只会调用

我有一个组件，它将显示两个Text相邻的项目列表。一个是标题，一个是内容。这是我的渲染实现：

let items = [
    {title: 'Test Test:', value: 'Long Test Long Test Long Test Long Test Long Test Long Test Long Test'},
    {title: 'Test:', value: 'Short Test Test Test'},
];
return (<FlatList
        style={{flex: 1, width: Dimensions.get('window').width}}
        data={items}
        renderItem={({item}) =>
            <View style={{flexDirection: 'row', width: Dimensions.get('window').width}}>
                <Text style={{color: colors.accentColor}}>{item.title}</Text>
                <Text>{item.value}</Text>
            </View>
        }/>);

问题是文本没有换行，当它是一个长文本时，它会进入屏幕。我该如何解决？

Launching lib\main.dart on STK LX1 in debug mode...

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:checkDebugAarMetadata'.
> Multiple task action failures occurred:
   > A failure occurred while executing com.android.build.gradle.internal.tasks.CheckAarMetadataWorkAction
      > The minCompileSdk (31) specified in a
        dependency's AAR metadata (META-INF/com/android/build/gradle/aar-metadata.properties)
        is greater than this module's compileSdkVersion (android-30).
        Dependency: androidx.window:window-java:1.0.0-beta04.
        AAR metadata file: C:\Users\Marwa\.gradle\caches\transforms-2\files-2.1\625039eaad011f884ddd84f857a44b7f\jetified-window-java-1.0.0-beta04\META-INF\com\android\build\gradle\aar-metadata.properties.
   > A failure occurred while executing com.android.build.gradle.internal.tasks.CheckAarMetadataWorkAction
      > The minCompileSdk (31) specified in a
        dependency's AAR metadata (META-INF/com/android/build/gradle/aar-metadata.properties)
        is greater …

即时通讯使用Android排球库为我的应用程序和当我使用wifi工作但它似乎有蜂窝数据连接的问题.在一些手机(LG G3 Android 6,魅族安卓5.1)与蜂窝数据它不起作用,并给出超时错误但在(HTC欲望816 android 4.4,LG g3 android 5.0)再次其工作

问题是什么？

logcat的:

D/ERROR: error => com.android.volley.TimeoutError

码:

showLoadingDialog();
StringRequest postRequest = new StringRequest(Request.Method.POST, url,
        new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                try {
                    JSONObject jobj = new JSONObject(response);
                    JSONObject jobjHRM = jobj.getJSONObject("HRM");
                    int status = jobjHRM.getInt("StatusCode");
                    if (status == 200) {
                        if (jobj.getJSONObject("Data").getBoolean("result") == true) {
                            login_info_editor.putInt("id", jobj.getJSONObject("Data").getInt("id"));
                            login_info_editor.putString("username", txtlayoutid.getEditText().getText().toString());
                                login_info_editor.putString("password", txtlayoutpass.getEditText().getText().toString());
                            login_info_editor.putBoolean("loged", true);
                            login_info_editor.commit();
                            checkversion();
                        } else {
                            login_info_editor.clear();
                            login_info_editor.commit();
                            txtlayoutid.requestFocus();
                            Toast.makeText(getApplicationContext(), "??? ?????? ?? ???? ? ???? …

最近我将我的xcode更新到8.0版和Alamofire 4.0.之后我得到Use of undeclared type 'Response'了这段代码:

func getDate(completion: (Response<AnyObject,NSError>) -> Void){
    Alamofire.request(.GET, "http://www.example.ir/api/utiliti/example" ,parameters:nil)
        .responseJSON{ response in
            completion(response)
    }
}

根据Apples API引用在此方法中重用视图

optional func pickerView(_ pickerView: UIPickerView, 
          viewForRow row: Int, 
        forComponent component: Int, 
             reusing view: UIView?) -> UIView

是一个由选择器视图的缓存视图,但当我尝试将它用于下一行时,它总是为零,而当我返回UILabel时,重用视图为零.问题是什么？这是我的实施:

func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
    let pickerLabel = UILabel()
    pickerLabel.textColor = UIColor.black
    pickerLabel.text = "10"
    pickerLabel.textAlignment = NSTextAlignment.center
    pickerLabel.sizeToFit()
    return pickerLabel
}

我正在尝试使用Firebase Analytics记录事件和当前屏幕,我在logcat中获取此日志:

App measurement is starting up, version: 9877
Registered activity lifecycle callback
Checking service availability
Service available
Connecting to remote service
onActivityCreated
Activity resumed, time: 234385086
Connected to remote service
Logging event (FE): _e, Bundle[{_o=auto, _et=9309, _sc=IntroActivity, _si=-6959962515326329023}]
setCurrentScreen cannot be called while no activity active
Logging event (FE): select_content, Bundle[{item_name=main, _o=app, content_type=image, item_id=1}]

这是我的代码:

mFirebaseAnalytics = FirebaseAnalytics.getInstance(this);
Bundle bundle = new Bundle();
bundle.putString(FirebaseAnalytics.Param.ITEM_ID, "1");
bundle.putString(FirebaseAnalytics.Param.ITEM_NAME, "main");
bundle.putString(FirebaseAnalytics.Param.CONTENT_TYPE, "image");
mFirebaseAnalytics.logEvent(FirebaseAnalytics.Event.SELECT_CONTENT, bundle);
mFirebaseAnalytics.setCurrentScreen(MainActivity.this,"Main","Home");

但在转到Firebase控制台后,我的应用程序中没有数据.为什么？