我正在Android Studio上开发自己的应用程序，并且整周无法解决以下所示的异常（我浏览了所有网站，但没有一个网站可以解决我的问题。
我有2个活动：
MainActivity.java
import android.graphics.Color;
import android.graphics.Typeface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.util.TypedValue;
import android.view.Gravity;
import android.widget.Button;
import android.content.Intent;
public class MainActivity extends AppCompatActivity {
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void toNextActivity(View view){
Intent intent = new Intent();
intent.setClass(MainActivity.this, SecondActivity.class);
startActivity(intent);
}
/**
* A native method that is implemented by the 'native-lib' native library,
* which is packaged with this application.
*/
public native String stringFromJNI();
}
SecondActivity.java
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;
import java.util.List;
public class SecondActivity extends AppCompatActivity
{
TextView trendText1;
TextView trendText2;
TextView trendText3;
TextView trendText4;
TextView trendText5;
TextView currentTrend;
private String databaseName = "xxxx";
private String mongodbUsername = "xxxx";
private String mongodbPassword = "xxxx";
private String clusterName = "xxxx";
public class getTrendFromDB extends AsyncTask<Void, Integer, Boolean> {
private String databaseName;
private String mongodbUsername;
private String mongodbPassword;
private String clusterName;
private List <String> keywordList;
protected getTrendFromDB(String db, String usr, String pwd, String cls) {
this.databaseName = db;
this.mongodbUsername = usr;
this.mongodbPassword = pwd;
this.clusterName = cls;
}
protected void onPreExecute() {
currentTrend.setText("Loading trend...");
}
protected Boolean doInBackground(Void... params) {
MongoClientURI uri = new MongoClientURI(
"mongodb+srv://" + this.mongodbUsername + ":" + this.mongodbPassword + "@" + this.clusterName
);
MongoClient mongoClient = new MongoClient(uri);
MongoDatabase dtsDatabase = mongoClient.getDatabase(this.databaseName);
MongoCollection<Document> keywordCollection = dtsDatabase.getCollection("trend_keywords");
MongoCursor<Document> cur = keywordCollection.find().iterator();
Document doc = cur.next();
this.keywordList = (List<String>) doc.get("list");
mongoClient.close();
return true;
}
protected void onProgressUpdate(Integer... values){
trendText1.setText(this.keywordList.get(0));
trendText2.setText(this.keywordList.get(1));
trendText3.setText(this.keywordList.get(2));
trendText4.setText(this.keywordList.get(3));
trendText5.setText(this.keywordList.get(4));
}
protected void onPostExecute(Boolean result) {
currentTrend.setText("finished!");
}
}
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
currentTrend = (TextView) findViewById(R.id.current_trend_text);
trendText1 = (TextView) findViewById(R.id.trendName1);
trendText2 = (TextView) findViewById(R.id.trendName2);
trendText3 = (TextView) findViewById(R.id.trendName3);
trendText4 = (TextView) findViewById(R.id.trendName4);
trendText5 = (TextView) findViewById(R.id.trendName5);
getTrendFromDB task1 = new getTrendFromDB(databaseName, mongodbUsername, mongodbPassword, clusterName);
task1.execute();
}
}
从MainActivity切换到第二个时，出现以下异常：
08-01 17:59:49.846 18046-18079/? E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: io.datats.dts_android.app, PID: 18046
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:354)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383)
at java.util.concurrent.FutureTask.setException(FutureTask.java:252)
at java.util.concurrent.FutureTask.run(FutureTask.java:271)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:764)
Caused by: java.lang.NoClassDefFoundError: Failed resolution of: Ljavax/naming/directory/InitialDirContext;
at com.mongodb.internal.dns.DnsResolver.createDnsDirContext(DnsResolver.java:140)
at com.mongodb.internal.dns.DnsResolver.resolveHostFromSrvRecords(DnsResolver.java:58)
at com.mongodb.ConnectionString.<init>(ConnectionString.java:325)
at com.mongodb.MongoClientURI.<init>(MongoClientURI.java:238)
at com.mongodb.MongoClientURI.<init>(MongoClientURI.java:220)
at io.datats.dts_android.forbole_dts.SecondActivity$getTrendFromDB.doInBackground(SecondActivity.java:46)
at io.datats.dts_android.forbole_dts.SecondActivity$getTrendFromDB.doInBackground(SecondActivity.java:27)
at android.os.AsyncTask$2.call(AsyncTask.java:333)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:764)
Caused by: java.lang.ClassNotFoundException: Didn't find class "javax.naming.directory.InitialDirContext" on path: DexPathList[[zip file "/data/app/io.datats.dts_android.app-g-9eU2fEIhL3iFJd3f_DWw==/base.apk", zip file "/data/app/io.datats.dts_android.app-g-9eU2fEIhL3iFJd3f_DWw==/split_forbole_dts.apk"],nativeLibraryDirectories=[/data/app/io.datats.dts_android.app-g-9eU2fEIhL3iFJd3f_DWw==/lib/x86, /data/app/io.datats.dts_android.app-g-9eU2fEIhL3iFJd3f_DWw==/base.apk!/lib/x86, /data/app/io.datats.dts_android.app-g-9eU2fEIhL3iFJd3f_DWw==/split_forbole_dts.apk!/lib/x86, /system/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:134)
at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
at com.mongodb.internal.dns.DnsResolver.createDnsDirContext(DnsResolver.java:140)
at com.mongodb.internal.dns.DnsResolver.resolveHostFromSrvRecords(DnsResolver.java:58)
at com.mongodb.ConnectionString.<init>(ConnectionString.java:325)
at com.mongodb.MongoClientURI.<init>(MongoClientURI.java:238)
at com.mongodb.MongoClientURI.<init>(MongoClientURI.java:220)
at io.datats.dts_android.forbole_dts.SecondActivity$getTrendFromDB.doInBackground(SecondActivity.java:46)
at io.datats.dts_android.forbole_dts.SecondActivity$getTrendFromDB.doInBackground(SecondActivity.java:27)
at android.os.AsyncTask$2.call(AsyncTask.java:333)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:764)
08-01 17:59:50.299 3661-3752/? E/InputDispatcher: channel 'c7cff48 io.datats.dts_android.app/io.datats.dts_android.forbole_dts.SecondActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
08-01 17:59:50.327 3661-3752/? E/InputDispatcher: channel '178d1a6 io.datats.dts_android.app/io.datats.dts_android.forbole_dts.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
08-01 17:59:52.693 1667-1735/? E/SurfaceFlinger: ro.sf.lcd_density must be defined as a build property
08-01 17:59:52.812 1667-1735/? E/SurfaceFlinger: ro.sf.lcd_density must be defined as a build property
08-01 17:59:58.052 3661-3680/? E/memtrack: Couldn't load memtrack module
08-01 17:59:58.067 3661-3680/? E/memtrack: Couldn't load memtrack module
08-01 17:59:58.072 3661-3680/? E/memtrack: Couldn't load memtrack module
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08-01 17:59:59.890 3661-3680/? E/memtrack: Couldn't load memtrack module
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08-01 18:00:00.030 3661-3680/? E/memtrack: Couldn't load memtrack module
08-01 18:00:00.085 3661-3680/? E/memtrack: Couldn't load memtrack module
08-01 18:00:08.303 3661-3680/? E/memtrack: Couldn't load memtrack module
08-01 18:00:17.691 3661-8661/? E/memtrack: Couldn't load memtrack module
08-01 18:00:19.284 1680-1756/? E/storaged: getDiskStats failed with result NOT_SUPPORTED and size 0
08-01 18:00:22.981 3661-3685/? E/BluetoothAdapter: Bluetooth binder is null
08-01 18:00:22.991 3661-3685/? E/KernelCpuSpeedReader: Failed to read cpu-freq: /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state (No such file or directory)
我已尝试根据搜索到的信息更改依赖关系，但失败了。这是我的build.gradle
build.gradle
apply plugin: 'com.android.feature'
android {
compileSdkVersion 28
defaultConfig {
minSdkVersion 15
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
externalNativeBuild {
cmake {
cppFlags ""
}
}
}
packagingOptions {
exclude 'META-INF/DEPENDENCIES'
exclude 'META-INF/LICENSE'
exclude 'META-INF/LICENSE.txt'
exclude 'META-INF/license.txt'
exclude 'META-INF/NOTICE'
exclude 'META-INF/NOTICE.txt'
exclude 'META-INF/notice.txt'
exclude 'META-INF/ASL2.0'
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {
cmake {
path "CMakeLists.txt"
}
}
sourceSets {
main {
assets.srcDirs = ['src/main/assets', 'src/main/assets/']
resources.srcDirs =['src/main/resources', 'src/main/resources/']
} }
}
dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation project(':base')
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
compile 'org.mongodb:mongo-java-driver:3.8.0'
compile "org.igniterealtime.smack:smack-android-extensions:4.1.8"
compile "org.igniterealtime.smack:smack-experimental:4.1.8"
compile "org.igniterealtime.smack:smack-tcp:4.1.8"
}
顺便说一句，用于SecondActivity.java的对MongoClientURI和MongoClient代码的相同请求在Eclipse Java上运行良好。我猜问题出在Android Studio包含的Java包中。谁能帮助我解决这个奇怪的问题？