在構建Project時，出現以下錯誤：app：compileDebugJava。它說錯誤：軟件包android.support.v7.app不存在

Question

我在模塊設置中具有所有必需的依賴關係。我還使用sdk管理器安裝了所有支持庫。

我從搖籃控制檯

Executing tasks: [:app:assembleDebug] 

Configuration on demand is an incubating feature. 
:app:preBuild 
:app:compileDebugNdk 
:app:preDebugBuild 
:app:checkDebugManifest 
:app:preReleaseBuild 
:app:prepareComAndroidSupportAppcompatV72103Library UP-TO-DATE 
:app:prepareComAndroidSupportSupportV42103Library UP-TO-DATE 
:app:prepareComGoogleAndroidGmsPlayServices6587Library UP-TO-DATE 
:app:prepareDebugDependencies 
:app:compileDebugAidl UP-TO-DATE 
:app:compileDebugRenderscript UP-TO-DATE 
:app:generateDebugBuildConfig UP-TO-DATE 
:app:generateDebugAssets UP-TO-DATE 
:app:mergeDebugAssets UP-TO-DATE 
:app:generateDebugResValues UP-TO-DATE 
:app:generateDebugResources UP-TO-DATE 
:app:mergeDebugResources UP-TO-DATE 
:app:processDebugManifest UP-TO-DATE 
:app:processDebugResources UP-TO-DATE 
:app:generateDebugSources UP-TO-DATE 
:app:compileDebugJava 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:4: error: package android.support.v7.app does not exist 
import android.support.v7.app.ActionBarActivity; 
          ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:11: error: cannot find symbol 
public class LoginConfim extends ActionBarActivity { 
           ^
    symbol: class ActionBarActivity 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:4: error: package android.support.v7.app does not exist 
import android.support.v7.app.ActionBarActivity; 
          ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:11: error: cannot find symbol 
public class RegistrationScreen extends ActionBarActivity { 
             ^
    symbol: class ActionBarActivity 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:4: error: package android.support.v7.app does not exist 
import android.support.v7.app.ActionBarActivity; 
          ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:11: error: cannot find symbol 
public class WelcomeScreen extends ActionBarActivity { 
           ^
    symbol: class ActionBarActivity 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:13: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:15: error: cannot find symbol 
     super.onCreate(savedInstanceState); 
     ^
    symbol: variable super 
    location: class LoginConfim 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:16: error: cannot find symbol 
     setContentView(R.layout.activity_login_confim); 
     ^
    symbol: method setContentView(int) 
    location: class LoginConfim 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:20: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:23: error: cannot find symbol 
     getMenuInflater().inflate(R.menu.menu_login_confim, menu); 
     ^
    symbol: method getMenuInflater() 
    location: class LoginConfim 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:27: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:39: error: cannot find symbol 
     return super.onOptionsItemSelected(item); 
      ^
    symbol: variable super 
    location: class LoginConfim 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:43: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), WelcomeScreen.class)); 
           ^
    symbol: method getApplicationContext() 
    location: class LoginConfim 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/LoginConfim.java:43: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), WelcomeScreen.class)); 
     ^
    symbol: method startActivity(Intent) 
    location: class LoginConfim 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:13: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:15: error: cannot find symbol 
     super.onCreate(savedInstanceState); 
     ^
    symbol: variable super 
    location: class RegistrationScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:16: error: cannot find symbol 
     setContentView(R.layout.activity_registration_screen); 
     ^
    symbol: method setContentView(int) 
    location: class RegistrationScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:20: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:23: error: cannot find symbol 
     getMenuInflater().inflate(R.menu.menu_registration_screen, menu); 
     ^
    symbol: method getMenuInflater() 
    location: class RegistrationScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:27: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:39: error: cannot find symbol 
     return super.onOptionsItemSelected(item); 
      ^
    symbol: variable super 
    location: class RegistrationScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:42: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), WelcomeScreen.class)); 
           ^
    symbol: method getApplicationContext() 
    location: class RegistrationScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/RegistrationScreen.java:42: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), WelcomeScreen.class)); 
     ^
    symbol: method startActivity(Intent) 
    location: class RegistrationScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:13: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:15: error: cannot find symbol 
     super.onCreate(savedInstanceState); 
     ^
    symbol: variable super 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:16: error: cannot find symbol 
     setContentView(R.layout.activity_welcome_screen); 
     ^
    symbol: method setContentView(int) 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:20: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:23: error: cannot find symbol 
     getMenuInflater().inflate(R.menu.menu_welcome_screen, menu); 
     ^
    symbol: method getMenuInflater() 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:27: error: method does not override or implement a method from a supertype 
    @Override 
    ^
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:39: error: cannot find symbol 
     return super.onOptionsItemSelected(item); 
      ^
    symbol: variable super 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:43: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), ShoppingWithFriendsLogin.class)); 
           ^
    symbol: method getApplicationContext() 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:43: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), ShoppingWithFriendsLogin.class)); 
     ^
    symbol: method startActivity(Intent) 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:47: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), RegistrationScreen.class)); 
           ^
    symbol: method getApplicationContext() 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:47: error: cannot find symbol 
     startActivity(new Intent(getApplicationContext(), RegistrationScreen.class)); 
     ^
    symbol: method startActivity(Intent) 
    location: class WelcomeScreen 
/Users/AMTAGRWL/Downloads/Dropbox/GT:CLASSES/Spring 2015/CS 2340/git/TrueProjectUnicorn/ShoppingWithFriends/app/src/main/java/com/projectunicorn/shoppingwithfriends/WelcomeScreen.java:50: error: method does not override or implement a method from a supertype 
    @Override 
    ^
36 errors 

FAILED 

FAILURE: Build failed with an exception. 

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

* Try: 
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. 

BUILD FAILED 

Total time: 2.692 secs 

我試圖對此多個現有職位，但都未能找到有效的解決方案如下輸出。

編輯：我的build.gradle文件。

apply plugin: 'com.android.application' 

android { 
    compileSdkVersion 21 
    buildToolsVersion "21.1.2" 

    defaultConfig { 
     applicationId "com.projectunicorn.shoppingwithfriends" 
     minSdkVersion 15 
     targetSdkVersion 21 
     versionCode 1 
     versionName "1.0" 
    } 
    buildTypes { 
     release { 
      minifyEnabled false 
      proguardFiles getDefaultProguardFile('proguard-android.txt'),      'proguard-rules.pro' 
     } 
    } 
} 

dependencies { 
    compile fileTree(dir: 'libs', include: ['*.jar']) 
    compile 'com.google.android.gms:play-services:6.5.87' 
    compile ('com.android.support:appcompat-v7:21.0.3') 
    compile ('com.android.support:support-v4:21.0.+') 
} 

我在OS X Yosemite上使用Android Studio 1.0.2。

Answer 1

安裝庫是不夠的。您還需要將其添加到項目的依賴項列表中。

要做到這一點，這一行添加到您的build.gradle的依賴關係部分：

dependencies { 
    ... 
    compile ('com.android.support:appcompat-v7:21.0.3') 
    compile ('com.android.support:support-v4:21.0.3') 
} 

這是從official docs採取：

v7 appcompat library

Note: This library depends on the v4 Support Library. If you are using Ant or Eclipse, make sure you include the v4 Support Library as part of this library's classpath.

所以，不要忘了加都v4和v7。

Answer 2

創建項目時您選擇了哪些版本？ （目標，最小等）

我將所有更改爲一個版本 - API 21，它適用於我。