Android Studio：java.lang.RuntimeException：無法啟動活動組件信息

Question

我正在嘗試將 AnyChart 模塊用於 Android Studio，但它一直給我錯誤java.lang.RuntimeException: Unable to start activity ComponentInfo 。

以下是一些值得注意的文件：

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import com.anychart.AnyChart;
import com.anychart.AnyChartView;
import com.anychart.chart.common.dataentry.DataEntry;
import com.anychart.chart.common.dataentry.ValueDataEntry;
import com.anychart.charts.Pie;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

            Pie pie = AnyChart.pie();
//
//        List<DataEntry> data = new ArrayList<>();
//        data.add(new ValueDataEntry("John", 10000));
//        data.add(new ValueDataEntry("Jake", 12000));
//        data.add(new ValueDataEntry("Peter", 18000));

        //AnyChartView anyChartView = (AnyChartView) findViewById(R.id.any_chart_view);
        //anyChartView.setChart(pie);
    }
}

build.gradle（項目）

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.0.1"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
        maven { url 'https://jitpack.io' }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

build.gradle（應用程序）

apply plugin: 'com.android.application'

android {
    compileSdkVersion 29
    buildToolsVersion "30.0.1"

    defaultConfig {
        applicationId "org.jack.project"
        minSdkVersion 21
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"

        multiDexEnabled true

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation 'com.github.AnyChart:AnyChart-Android:1.1.2'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

<!--    <com.anychart.anychart.AnyChartView-->
<!--        android:id="@+id/any_chart_view"-->
<!--        android:layout_width="match_parent"-->
<!--        android:layout_height="match_parent"-->
<!--        />-->


</androidx.constraintlayout.widget.ConstraintLayout>

這是錯誤：

    Process: org.jack.project, PID: 956
    java.lang.RuntimeException: Unable to start activity ComponentInfo{org.jack.project/org.jack.project.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.anychart.AnyChartView$JsListener com.anychart.AnyChartView.getJsListener()' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.anychart.AnyChartView$JsListener com.anychart.AnyChartView.getJsListener()' on a null object reference
        at com.anychart.APIlib.addJSLine(APIlib.java:27)
        at com.anychart.charts.Pie.<init>(Pie.java:34)
        at com.anychart.AnyChart.pie(AnyChart.java:130)
        at org.jack.project.MainActivity.onCreate(MainActivity.java:23)
        at android.app.Activity.performCreate(Activity.java:7802)
        at android.app.Activity.performCreate(Activity.java:7791)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7356) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 

我已經嘗試過清理/清除緩存/重新啟動/同步我的 gradle 文件。

在模擬器上，它說我的應用程序不斷重啟。

謝謝您的幫助。

Answer 1

根本原因

我瀏覽了AnyChart-Android源代碼並弄清楚了代碼流程。

步驟 1.從我們的應用程序 Activity/Fragment

Pie pie = AnyChart.pie();

步驟 2. AnyChart.java

public static com.anychart.charts.Pie pie() {
    return new com.anychart.charts.Pie("anychart.pie()");
}

步驟 3. Pie.java

public Pie(String jsChart) {
    jsBase = "pie" + ++variableIndex;
    APIlib.getInstance().addJSLine(jsBase + " = " + jsChart + ";");
}

步驟 4. APIlib.java

public class APIlib {

    private AnyChartView anyChartView;

    private static volatile APIlib instance;

    public static APIlib getInstance() {
        APIlib localInstance = instance;
        if (localInstance == null) {
            synchronized (APIlib.class) {
                localInstance = instance;
                if (localInstance == null) {
                    instance = localInstance = new APIlib();
                }
            }
        }
        return localInstance;
    }

    public void setActiveAnyChartView(AnyChartView anyChartView) {
        this.anyChartView = anyChartView;
    }

    public void addJSLine(String jsLine) {
        anyChartView.getJsListener().onJsLineAdd(jsLine);
    }
}

正如我們看到的，當我們調用addJSLine(String)方法時，它調用了 anyChartView 的anyChartView getJsListener()方法，但是這個實例只能通過setActiveAnyChartView方法設置。 而且此方法僅從AnyChartView.java調用。

@SuppressLint({"SetJavaScriptEnabled", "AddJavascriptInterface"})
private void init() {
    ...

    APIlib.getInstance().setActiveAnyChartView(this);

    ...
}

init()方法將在AnyCharView class 的構造函數中調用。

public AnyChartView(Context context) {
    super(context);
    init();
}

public AnyChartView(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
    init();
}

public AnyChartView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    init();
}

因為在activity_main.xml里面，你注釋掉代碼

<!--    <com.anychart.anychart.AnyChartView-->
<!--        android:id="@+id/any_chart_view"-->
<!--        android:layout_width="match_parent"-->
<!--        android:layout_height="match_parent"-->
<!--        />-->

這就解釋了為什么你得到了例外。

解決方案：確保至少創建了一個AnyChartView實例。

解決方案 1.在 xml 文件中聲明AnyCharView

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.anychart.AnyChartView
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</FrameLayout>

解決方案 2.如果要在運行時添加AnyChartView ，則可以使用

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val anyChartView = AnyChartView(this)

        val pie: Pie = AnyChart.pie()
    }
}

注意：我看到這里已經報告了這個問題，但還沒有答案。