Question

首先让我先展示一下代码：

build.gradle（module）：

android {
compileSdkVersion 24
buildToolsVersion "24.0.2"
dataBinding {
    enabled = true
}
defaultConfig {
    applicationId "com.example.oryaa.basecalculator"
    minSdkVersion 15
    targetSdkVersion 24
    versionCode 1
    versionName "1.0"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}


dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:24.2.1'
compile 'com.google.android.gms:play-services-appindexing:8.1.0'

activity_main.xml中：

<data>
    <import type="android.view.View" />
    <variable
        name="baseCalcModel"
        type="com.example.oryaa.basecalculator.BaseCalcModel">
    </variable>
</data>  <TextView
        android:id="@+id/resultOutput"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/resultTextView"
        android:textColor="@color/DarkBlue"
        android:text="@{baseCalcModel.calcResult}"
        android:textSize="32dp" />

MainActicity.java：

public class MainActivity extends AppCompatActivity {

EditText userInput = null;
TextView resultTV = null;
Spinner fromBaseSpinner = null;
Spinner toBaseSpinner = null;
ArrayList<String> spinnerArray = new ArrayList<>();
String _allowedChars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String _onlyOnceChar = "-+*/";
BaseCalcModel baseCalcModel = new BaseCalcModel();

/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
private GoogleApiClient client;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
    binding.setBaseCalcModel(this.baseCalcModel);
    this.resultTV = (TextView) this.findViewById(R.id.resultOutput);
    this.fromBaseSpinner = (Spinner) findViewById(R.id.fromBaseSpinner);
    this.toBaseSpinner = (Spinner) findViewById(R.id.toBaseSpinner);
    this.userInput = (EditText) findViewById(R.id.userInput);
    SetupUI();
    baseCalcModel.setCalcResult("test");

    // ATTENTION: This was auto-generated to implement the App Indexing API.
    // See https://g.co/AppIndexing/AndroidStudio for more information.
    client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}

BaseCalcModel.java：

ublic class BaseCalcModel extends BaseObservable {


public String calcResult;
public BaseView firstNumView;
public BaseView secondNumView;
public BaseView resultNumView;
public int firstNumBase;
public int secondNumBase;
public int resultNumBase;
public String error;


@Bindable
String getCalcResult() {
    return calcResult;
}

@Bindable
public BaseView getFirstNumView() {
    return firstNumView;
}

@Bindable
public BaseView getSecondNumView() {
    return secondNumView;
}

@Bindable
public BaseView getResultNumView() {
    return this.resultNumView;
}

@Bindable
public int getFirstNumBase() {
    return this.firstNumBase;
}

@Bindable
public int getSecondNumBase() {
    return this.secondNumBase;
}

@Bindable
public int getResultNumBase() {
    return this.resultNumBase;
}

@Bindable
public String getError() {
    return this.error;
}

public void setCalcResult(String calcResult) {
    this.calcResult = calcResult;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.calcResult);
}

public void setFirstNumView(BaseView firstNumView) {
    this.firstNumView = firstNumView;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.firstNumView);
}

public void setSecondNumView(BaseView secondNumView) {
    this.secondNumView = secondNumView;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.secondNumView);
}

public void setResultNumView(BaseView resultNumView) {
    this.resultNumView = resultNumView;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.resultNumView);
}

public void setFirstNumBase(int firstNumBase) {
    this.firstNumBase = firstNumBase;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.firstNumBase);
}

public void setSecondNumBase(int secondNumBase) {
    this.secondNumBase = secondNumBase;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.secondNumBase);
}

public void setResultNumBase(int resultNumBase) {
    this.resultNumBase = resultNumBase;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.resultNumBase);
}

public void setError(String error) {
    this.error = error;
    notifyPropertyChanged(com.example.oryaa.basecalculator.BR.error);
}


public BaseCalcModel() {
    firstNumView = new BaseView();
    secondNumView = new BaseView();
    resultNumView = new BaseView();
    firstNumBase = 0;
    secondNumBase = 0;
    resultNumBase = 0;
    calcResult = "";
    error = "";
}

public BaseCalcModel(BaseView firstNumView, BaseView secondNumView, BaseView resultNumView,
                     int firstNumBase, int secondNumBase, int resultNumBase, String clcResult,
                     String error) {
    this.firstNumView = firstNumView;
    this.secondNumView = secondNumView;
    this.resultNumView = resultNumView;
    this.firstNumBase = firstNumBase;
    this.secondNumBase = secondNumBase;
    this.resultNumBase = resultNumBase;
    this.calcResult = clcResult;
    this.error = error;
}

我试图做简单的数据绑定，但我的观点在proparty改变后没有更新。正如你在图像中看到的那样，我的代码到达：

            notifyPropertyChanged(com.example.oryaa.basecalculator.BR.calcResult);

但视图仅在应用程序启动时或当我将手机旋转为垂直水平或反之亦然时更新。

我的问题在哪里？

非常感谢，或Yaacov

Answer 1

在事件发生后需要刷新视图时，我遇到了类似的问题，但变量对象不可观察，所以我添加了以下内容：

 - schedule:
          name: lambda-warmer-scheduler
          description: 'scheduler to warmup lambdas '
          rate: rate(2 minutes)

希望对您有帮助。

Answer 2

您需要调用<div>Email Address: {{account.accountprofile.emailaddresses.0.emailaddress}}</div>以立即更新视图中的绑定值：

当变量或可观察变化时，绑定将被安排在下一帧之前变化。但是，有时必须立即执行绑定。要强制执行，请使用executePendingBindings（）方法。

查看Advanced Binding章节了解更多信息

Answer 3

如果您可能遇到groupplot的此问题，则可能忘了添加LiveData。

Answer 4

将模型类字段设为私有。
更改getCalcResult()应该是公开的。
BaseView应该扩展BaseObservable
如果不动态更改模型值。然后，您不必使每个访问者都@Bindable。您可以删除它。并删除notifyPropertyChanged()。相反，如果您需要动态更改模型值，则使用@Bindable属性。

您很高兴。

public class BaseCalcModel extends BaseObservable {
private String calcResult;
private BaseView firstNumView;
private BaseView secondNumView;
private BaseView resultNumView;
private int firstNumBase;
private int secondNumBase;
private int resultNumBase;
private String error;

public String getCalcResult() {
    return calcResult;
}

public void setCalcResult(String calcResult) {
    this.calcResult = calcResult;
}

public BaseView getFirstNumView() {
    return firstNumView;
}

public void setFirstNumView(BaseView firstNumView) {
    this.firstNumView = firstNumView;
}

public BaseView getSecondNumView() {
    return secondNumView;
}

public void setSecondNumView(BaseView secondNumView) {
    this.secondNumView = secondNumView;
}

public BaseView getResultNumView() {
    return resultNumView;
}

public void setResultNumView(BaseView resultNumView) {
    this.resultNumView = resultNumView;
}

public int getFirstNumBase() {
    return firstNumBase;
}

public void setFirstNumBase(int firstNumBase) {
    this.firstNumBase = firstNumBase;
}

public int getSecondNumBase() {
    return secondNumBase;
}

public void setSecondNumBase(int secondNumBase) {
    this.secondNumBase = secondNumBase;
}

public int getResultNumBase() {
    return resultNumBase;
}

public void setResultNumBase(int resultNumBase) {
    this.resultNumBase = resultNumBase;
}

public String getError() {
    return error;
}

public void setError(String error) {
    this.error = error;
}

}

Answer 5

当数据绑定对您不起作用时，请确保您正在更新the same object field。 The object's instance必须相同才能更新UI。也许我的回答对某人有帮助，喜欢编码！

Answer 6

我遇到了完全相同的问题。显然，这是导致问题的一条线。您所要做的就是将 licycleowner 设置为 binding。

binding.lifecycleOwner = this

Answer 7

就我而言，我忘记了 setContentView(binding.root)。我使用 ResultReceiver 作为我的 Activity 类的子类。按照设置 documentation 之后，我得到了这个：

class MyActivity : AppCompatActivity(), AdapterView.OnItemSelectedListener, ServiceConnection {

    lateinit var txtV     : TextView
    lateinit var binding  : MyActivityBinding
    lateinit var receiver : MyResultReceiver

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = MyActivityBinding.inflate(layoutInflater)
        setContentView(binding.root)                           // <--
        receiver = MyResultReceiver(Handler(), binding)
        ...
    }

    class MyResultReceiver(handler: Handler?, binding : MyActivityBinding) : ResultReceiver(handler) {
        private var mBinding = binding
        override fun onReceiveResult(resultCode: Int, resultData: Bundle?) {
            mBinding.txtV.append("\n${resultData?.getString("theTag")}")
        }
    }
}

Android数据绑定：更改属性时视图不会更新

7 个答案: