getActivity（）在我的ActivityInstrumentationTestCase2类中返回一个空值 [英] getActivity() returns a null in my ActivityInstrumentationTestCase2 class

问题描述

我希望我的应用程序使用ActivityInstrumentationTestCase2在代码中执行以下测试。问题是getActivity（）方法返回null。这会在包含getActivity（）的行的正下方的行处产生NullPointerException。结果，测试无法运行。我不知道它为什么这样做。我已经尝试将@Before改为@Override，但问题仍然存在。

以下是实际的Test类：

  package com.example.guy.smsclassprojecttest; 
 
导入android.test.ActivityInstrumentationTestCase2; 
导入android.test.suitebuilder.annotation.SmallTest; 
导入android.widget.Button; 
导入android.widget.EditText; 
 
 import com.example.guy.smsclassproject。*; 
 
 import org.junit。*; 
 import org.junit.Test; 
 
 import java.util.ArrayList; 
 
 
 public class DraftsActivityTest2 extends ActivityInstrumentationTestCase2< DraftsActivity> 
 {
 private EditText searchText; 
私人按钮searchButton; 
 private DraftsDatabase draftsDatabase; 
 ArrayList< MessageObject> messagesToBeDisplayed; 
 DraftsActivity测试人员; 
 
 public DraftsActivityTest2（）
 {
 super（DraftsActivity.class）; 
 
 
 $ b @Before 
 public void setUp（）throws Exception 
 {
 
 draftsDatabase = new DraftsDatabase（）; 
 MessageObject messageObject1 = new MessageObject（hi，5554，true）; 
 MessageObject messageObject2 = new MessageObject（hi hi，5555554，true）; 
 MessageObject messageObject3 = new MessageObject（sup，5435555554，true）; 
 draftsDatabase.addMessage（messageObject1）; 
 draftsDatabase.addMessage（messageObject2）; 
 draftsDatabase.addMessage（messageObject3）; 
 messagesToBeDisplayed = draftsDatabase.getAllTexts（）; 
 //这里是代码崩溃的地方
 tester = getActivity（）; 
 messagesToBeDisplayed = tester.messagesToBeDisplayed; 
 searchText =（EditText）tester.findViewById（R.id.searchText）; 
 searchButton =（Button）tester.findViewById（R.id.searchButton）; 
} 
 
 @Test 
 public void testSearch（）{
 
 searchText.setText（hi）; 
 searchButton.performClick（）; 
 messagesToBeDisplayed = draftsDatabase.getMessagesByKey（searchText.getText（）。toString（））; 
 Assert.assertEquals（Messages with the word hi，2，messagesToBeDisplayed.size（））; 
 Assert.assertTrue（false）; 
 
 
 $ / code $ 
 
 
 
这里是清单文件和gradle文件，如果它们有所作为： 
 
 
清单文件： 
 
 
 <？xml version =1.0encoding =utf-8？> 
< manifest xmlns：android =http://schemas.android.com/apk/res/android
 package =com.example.guy.smsclassproject> 
 
< uses-sdk android：minSdkVersion =10/> 
 android：versionCode =1
 android：versionName =1.0> 
< uses-permission android：name =android.permission.SEND_SMS/> 
< uses-permission android：name =android.permission.RECEIVE_SMS/> 
<使用权限android：name =android.permission.READ_CONTACTS/> 
 
<使用权限android：name =android.permission.WRITE_EXTERNAL_STORAGE/> 
<使用权限android：name =android.permission.READ_PHONE_STATE/> 
<使用权限android：name =android.permission.READ_EXTERNAL_STORAGE/> 
 
 $ b< application 
 android：allowBackup =true
 android：icon =@ mipmap / ic_launcher
 android：label =SMS 
 android：supportsRtl =true
 android：theme =@ style / AppTheme> 
 
 <！ - 主菜单 - > 
< activity android：name =。MenuActivityandroid：label =SMS> 
< intent-filter> 
  
< category android：name =android.intent.category.LAUNCHER/> 
< / intent-filter> 
< / activity> 
 
 <！ - 草稿 - > 
< activity android：name =。DraftsActivity
 android：label =草稿
 android：windowSoftInputMode =adjustPan> <！ - 停止键盘搞乱布局 - > 
< / activity> 
 
<！ - 历史记录 - > 
< activity 
 android：name =。HistoryActivity
 android：label =最近文本
 android：windowSoftInputMode =adjustPan> <！ - 停止键盘搞乱布局 - > 
< / activity> 
 
 <！ -   - 文字 - > 
< activity 
 android：name =。TextingActivity
 android：label =发短信
 android：windowSoftInputMode =adjustPan> <！ - 停止键盘搞乱布局 - > 
< / activity> 
 
< receiver android：name =。SmsReceiver> 
< intent-filter> 
 < / intent-filter> 
< / receiver> 
 
< activity 
 android：name =。SingleTextActivity
 android：label =Message> // http：//stackoverflow.com/questions/2198410/如何更改Android中的活动标题 -  Tian 
< / activity> 
< / application> 
 
< / manifest> 
  
 Gradle： 
 
 
  apply plugin：'com.android.application'
 
 android {
 compileSdkVersion 23 
 buildToolsVersion23.0.1
 
 defaultConfig {
的minSdkVersion 15 
 targetSdkVersion 23 
的versionCode 1个
的versionName 1.0 
 testApplicationId 'com.example.guy.smsclassprojecttest' 
 
 
} 
 buildTypes {
释放{
 minifyEnabled假
 proguardFiles getDefaultProguardFile（ 'proguard的-android.txt'）， 'proguard-rules.pro' 
} 
} 
 
 testOptions {
 
 unitTests.returnDefaultValues = true 
 
} 
 
 defaultConfig 
 {
 testInstrumentationRunnerandroid.support.test.runner.AndroidJUnitRunner
} 
} 
 
 
依赖关系{
编译fileTree（dir： 'libs'，包括：[' * .jar']）
 testCompile'junit：junit：4.12'
 compile'c​​om.android.support:appcompat-v7:23.1.0'
 compile'c​​om.android.support： design：23.1.0'
 androidTestCompile'c​​om.android.support.test.espresso：espresso-core：2.0'
 androidTestCompile'c​​om.android.support.test：testing-support-lib：0.1' 
 testCompile'junit：junit：4.12'
} 
  
 
 
解决方案
如果您使用的是ActivityInstrumentationTestCase2，则不需要@Before，@Test注释。  
 
 
有两种方法可以使用： 
 
 
 
 
继续使用ActivityInstrumentationTestCase2来测试这个Activity，从你的代码中删除所有的@Before @Test注解，并且测试用例应该没有问题地运行。
 
不要继承ActivityInstrumentationTestCase2，而是使用AndroidJUnitRunner，并设置通过设置活动测试规则像这样
 
 
 
 
 
 
 
 JUnit4下的测试用例：
 
 
 
 
 
  public class DraftsActivityTest2 {
 
 @Rule 
 public ActivityTestRule< DraftsActivity> mActivityRule = new ActivityTestRule<>（
 DraftsActivity.class）; 
 
 @Before 
 public void setUp（）{
 DraftsActivity activity = mActivityRule.getActivity（）; 
 ...} 
} 
  
 
I want my app to perform the following test in the code with ActivityInstrumentationTestCase2. The problem is the getActivity() method returns a null. This results in a NullPointerException at the line directly underneath the line that contains getActivity(). As a result, the test cannot run. I don't know why it is doing that. I have already tried changing @Before to @Override but the problem continues.


Here is the actual Test class:
package com.example.guy.smsclassprojecttest;

import android.test.ActivityInstrumentationTestCase2;
import android.test.suitebuilder.annotation.SmallTest;
import android.widget.Button;
import android.widget.EditText;

import com.example.guy.smsclassproject.*;

import org.junit.*;
import org.junit.Test;

import java.util.ArrayList;


public class DraftsActivityTest2 extends ActivityInstrumentationTestCase2<DraftsActivity>
{
    private EditText searchText;
    private Button searchButton;
    private DraftsDatabase draftsDatabase;
    ArrayList<MessageObject> messagesToBeDisplayed;
    DraftsActivity tester;

    public DraftsActivityTest2()
    {
        super(DraftsActivity.class);

    }

    @Before
    public void setUp() throws Exception
    {

        draftsDatabase = new DraftsDatabase();
        MessageObject messageObject1 = new MessageObject("hi", "5554", true);
        MessageObject messageObject2 = new MessageObject("hi hi", "5555554", true);
        MessageObject messageObject3 = new MessageObject("sup", "5435555554", true);
        draftsDatabase.addMessage(messageObject1);
        draftsDatabase.addMessage(messageObject2);
        draftsDatabase.addMessage(messageObject3);
        messagesToBeDisplayed = draftsDatabase.getAllTexts();
        //Here is where the code crashes
        tester = getActivity();
        messagesToBeDisplayed = tester.messagesToBeDisplayed;
        searchText = (EditText) tester.findViewById(R.id.searchText);
        searchButton = (Button) tester.findViewById(R.id.searchButton);
    }

    @Test
    public void testSearch() {

        searchText.setText("hi");
        searchButton.performClick();
        messagesToBeDisplayed = draftsDatabase.getMessagesByKey(searchText.getText().toString());
        Assert.assertEquals("Messages with the word hi", 2, messagesToBeDisplayed.size());
        Assert.assertTrue(false);
    }
}
Here is the manifest file and the gradle file if they make a difference:

Manifest File:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.guy.smsclassproject" >

    <uses-sdk android:minSdkVersion="10" />
    android:versionCode="1"
    android:versionName="1.0">
    <uses-permission android:name="android.permission.SEND_SMS" />
    <uses-permission android:name="android.permission.RECEIVE_SMS" />
    <uses-permission android:name="android.permission.READ_CONTACTS" />

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />


    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="SMS"
        android:supportsRtl="true"
        android:theme="@style/AppTheme" >

        <!-- main menu -->
        <activity android:name=".MenuActivity" android:label="SMS">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <!-- Drafts -->
        <activity android:name=".DraftsActivity"
            android:label="Drafts"
            android:windowSoftInputMode="adjustPan"> <!-- stops keyboard from messing up layout -->
        </activity>

        <!-- History -->
        <activity
            android:name=".HistoryActivity"
            android:label="Recent Texts"
            android:windowSoftInputMode="adjustPan"> <!-- stops keyboard from messing up layout -->
        </activity>

        <!-- Texts -->
        <activity
            android:name=".TextingActivity"
            android:label="Texting"
            android:windowSoftInputMode="adjustPan" > <!-- stops keyboard from messing up layout -->
        </activity>

        <receiver android:name=".SmsReceiver" >
            <intent-filter>
                <action android:name="android.provider.Telephony.SMS_RECEIVED" />
            </intent-filter>
        </receiver>

        <activity
            android:name=".SingleTextActivity"
            android:label="Message" >//http://stackoverflow.com/questions/2198410/how-to-change-title-of-activity-in-android--Tian
        </activity>
    </application>

</manifest>
Gradle:
apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.1"

    defaultConfig {
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        testApplicationId 'com.example.guy.smsclassprojecttest'


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

    testOptions {

        unitTests.returnDefaultValues = true

    }

    defaultConfig
    {
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
}


dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.0'
    compile 'com.android.support:design:23.1.0'
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.0'
    androidTestCompile 'com.android.support.test:testing-support-lib:0.1'
    testCompile 'junit:junit:4.12'
}

解决方案
If you are using ActivityInstrumentationTestCase2, you don't need the @Before, @Test annotations. 

There are 2 ways to go:

Continue to use ActivityInstrumentationTestCase2 to test this Activity, remove all the @Before @Test annotations from your code, and the test case should run without a problem.
Don't subclass ActivityInstrumentationTestCase2, instead,  to use AndroidJUnitRunner, and set the Activity by setting the activity test rule like this 



  
Test case under JUnit4:


public class DraftsActivityTest2 {

@Rule
public ActivityTestRule<DraftsActivity> mActivityRule = new ActivityTestRule<>(
        DraftsActivity.class);

@Before
public void setUp(){
    DraftsActivity activity = mActivityRule.getActivity();
    ...}
}


                        
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