java - 使用Gradle编译Android项目时出现"Error: cannot find symbol"

Question

由于以下错误，我无法使用 Gradle 编译我的 Android 项目:

:compileDebugJava
(...)/src/org/drzewo/openmrs/android/andromeda/dialog/DateTimeFragment.java:101: error: cannot find symbol
    public interface Callbacks extends ActivityCallbacks {
                                       ^
  symbol:   class ActivityCallbacks
  location: class DateTimeFragment
(...)/src/org/drzewo/openmrs/android/andromeda/dialog/DateTimeFragment.java:53: error: method asCallbacks in class Util cannot be applied to given types;
        mPickerOptions = Util.asCallbacks(activity, Callbacks.class).getPickerOptions();
                             ^
  required: Activity,Class<T>
  found: Activity,Class<Callbacks>
  reason: inferred type does not conform to declared bound(s)
    inferred: Callbacks
    bound(s): ActivityCallbacks
  where T is a type-variable:
    T extends ActivityCallbacks declared in method <T>asCallbacks(Activity,Class<T>)
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
2 errors
:compileDebugJava FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileDebugJava'.
> Compilation failed; see the compiler error output for details.

有问题的源文件是:

package org.drzewo.openmrs.android.andromeda.dialog;

import java.util.Calendar;

import org.drzewo.openmrs.android.andromeda.R;
import org.drzewo.openmrs.android.andromeda.dialog.DateTimePickerActivity.PickerOptions;
import org.drzewo.openmrs.android.andromeda.event.OnDateTimeSelected;
import org.drzewo.openmrs.android.andromeda.util.ActivityCallbacks;
import org.drzewo.openmrs.android.andromeda.util.Util;

import roboguice.event.EventManager;
import roboguice.fragment.RoboFragment;
import roboguice.inject.InjectView;
import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TimePicker;

import com.google.inject.Inject;

public class DateTimeFragment extends RoboFragment implements OnClickListener {

    @Inject
    private EventManager mEventManager;

    @InjectView(R.id.date)
    private DatePicker mDate;

    @InjectView(R.id.time)
    private TimePicker mTime;

    @InjectView(R.id.ok_button)
    private Button mOkButton;

    private PickerOptions mPickerOptions;

    public DateTimeFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        mPickerOptions = Util.asCallbacks(activity, Callbacks.class).getPickerOptions();
        if (mPickerOptions == null) {
            throw new IllegalArgumentException("No picker options provided");
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_date_time, container, false);
    }

    @SuppressWarnings("incomplete-switch")
    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        switch (mPickerOptions) {
        case DATE:
            mTime.setVisibility(View.GONE);
            break;
        case TIME:
            mDate.setVisibility(View.GONE);
            mTime.setIs24HourView(true);
            break;
        }
        mOkButton.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (mOkButton == v) {
            final Calendar calendar = Calendar.getInstance();
            switch (mPickerOptions) {
            case DATE:
                calendar.set(mDate.getYear(), mDate.getMonth(), mDate.getDayOfMonth());
                break;
            case TIME:
                calendar.set(0, 0, 0, mTime.getCurrentHour(), mTime.getCurrentMinute());
                break;
            case DATE_TIME:
                calendar.set(mDate.getYear(), mDate.getMonth(), mDate.getDayOfMonth(),
                        mTime.getCurrentHour(), mTime.getCurrentMinute());
                break;
            }
            mEventManager.fire(new OnDateTimeSelected(calendar.getTime()));
        }
    }

    public interface Callbacks extends ActivityCallbacks {
        PickerOptions getPickerOptions();
    }
}

看起来像

import org.drzewo.openmrs.android.andromeda.util.ActivityCallbacks;

线路无法正常工作，但如果我更改

public interface Callbacks extends ActivityCallbacks {

行至

public interface Callbacks extends org.drzewo.openmrs.android.andromeda.util.ActivityCallbacks {

然后一切正常。

所以我知道解决方法，但只是不想在不了解问题根源的情况下应用它。导入行是有效的，在其他几个文件中完全相同的解决方案不会导致任何错误。当我使用 Eclipse 而不是 Gradle 来构建项目时，一切正常。

这是我的 build.gradle 脚本:

buildscript {
    repositories {
        mavenCentral()
    }

    dependencies {
        classpath 'org.xtend:xtend-gradle-plugin:0.1.+'
        classpath 'com.android.tools.build:gradle:0.12.+'
    }
}

apply plugin: 'xtend-android'
apply plugin: 'android'
apply plugin: 'eclipse'

group = projectGroup
version = projectVersion

sourceCompatibility = 1.6
targetCompatibility = 1.6

repositories {
    mavenLocal()
    mavenCentral()
}

dependencies {
    compile 'org.eclipse.xtend:org.eclipse.xtend.lib:2.6.2'
    compile 'com.android.support:support-v4:20.0.0'
    compile 'org.drzewo.openmrs:jomrsa:0.8.0'
    compile 'org.roboguice:roboguice:2.0'
    compile 'commons-codec:commons-codec:1.8'
    compile 'org.apache.httpcomponents:httpclient-android:4.3.3'
}

android {
    compileSdkVersion 15
    buildToolsVersion '20.0.0'

    sourceSets {
        main {
            manifest.srcFile 'AndroidManifest.xml'
            java.srcDirs = ['src']
            resources.srcDirs = ['src']
            aidl.srcDirs = ['src']
            renderscript.srcDirs = ['src']
            res.srcDirs = ['res']
            assets.srcDirs = ['assets']
            resources {
                exclude '**/*.xtend'
            }
        }

        instrumentTest.setRoot('tests')

        debug.setRoot('build-types' + File.separator + 'debug')
        release.setRoot('build-types' + File.separator + 'release')
    }

    packagingOptions {
        pickFirst 'META-INF/LICENSE'
        pickFirst 'META-INF/NOTICE'
    }

    lintOptions {
        abortOnError false
    }
}

eclipse {
    project {
        name = rootProject.name

        buildCommands = [
            'org.eclipse.xtext.ui.shared.xtextBuilder',
            'com.android.ide.eclipse.adt.ResourceManagerBuilder',
            'com.android.ide.eclipse.adt.PreCompilerBuilder',
            'org.eclipse.jdt.core.javabuilder',
            'com.android.ide.eclipse.adt.ApkBuilder'
        ]

        natures = [
            'org.springsource.ide.eclipse.gradle.core.nature',
            'org.eclipse.xtext.ui.shared.xtextNature',
            'com.android.ide.eclipse.adt.AndroidNature',
            'org.eclipse.jdt.core.javanature'
        ]
    }
}

task wrapper(type: Wrapper) {
    gradleVersion = '1.12'
}

apply from: 'gradle' + File.separator + 'copyLibs.gradle'

所以问题是:为什么我会遇到这个问题以及我应该如何解决它？

PS。如果有人想编译上述项目:它托管在 Fossil 存储库 here 中，其依赖的项目为 here (也在化石库中)。服务器使用自签名证书，因此浏览器可能会提示。

Answer 1

我记得，这是因为其中一个模块缺少 build.gradle 。