java - 导入 android.support.v4 包时遇到问题

Question

我正在尝试将 android-support-v4.jar 包含到我的命令行 android 项目中。我的导入语句很简单:

import android.support.v4.NavUtils;

我已经将 jar 从 $ANDROID_HOME/extras/android/support/v4/android-support-v4.jar 复制到我项目的 libs/ 文件夹中，但是我使用 ant 构建时仍然收到以下错误:

package android.support.v4 does not exist

我的理解是，libs/ 文件夹中的任何 jar 都会自动包含在项目类路径中。

根据要求，ls -l 在根项目文件夹中的输出是

-rw-r--r--   1 Nick  staff  1192  4 Jan 15:08 AndroidManifest.xml
-rw-r--r--   1 Nick  staff   696  4 Jan 12:12 ant.properties
drwxr-xr-x  17 Nick  staff   578  4 Jan 15:10 bin
-rw-r--r--   1 Nick  staff  3922  3 Jan 14:08 build.xml
drwxr-xr-x   4 Nick  staff   136  3 Jan 15:11 gen
drwxr-xr-x   3 Nick  staff   102  4 Jan 15:18 libs
-rw-r--r--   1 Nick  staff   441  3 Jan 14:08 local.properties
-rw-r--r--   1 Nick  staff   781  3 Jan 14:08 proguard-project.txt
-rw-r--r--   1 Nick  staff   563  3 Jan 14:08 project.properties
drwxr-xr-x   8 Nick  staff   272  3 Jan 14:08 res
drwxr-xr-x   3 Nick  staff   102  3 Jan 14:08 src

ant debug 的整个输出是

    Buildfile: /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/build.xml

-set-mode-check:

-set-debug-files:

-check-env:
 [checkenv] Android SDK Tools Revision 21.0.1
 [checkenv] Installed at /Users/Nick/Development/SDKS/android-sdk-macosx

-setup:
     [echo] Project Name: MyFirstApp
  [gettype] Project Type: Application

-set-debug-mode:

-debug-obfuscation-check:

-build-setup:
     [echo] Resolving Build Target for MyFirstApp...
[gettarget] Project Target:   Android 4.2
[gettarget] API level:        17
     [echo] ----------
     [echo] Creating output directories if needed...
     [echo] ----------
     [echo] Resolving Dependencies for MyFirstApp...
[dependency] Library dependencies:
[dependency] No Libraries
     [echo] ----------
     [echo] Building Libraries with 'debug'...
   [subant] No sub-builds to iterate on

-pre-build:

-code-gen:
[mergemanifest] No changes in the AndroidManifest files.
     [echo] Handling aidl files...
     [aidl] No AIDL files to compile.
     [echo] ----------
     [echo] Handling RenderScript files...
[renderscript] No RenderScript files to compile.
     [echo] ----------
     [echo] Handling Resources...
     [aapt] No changed resources. R.java and Manifest.java untouched.
     [echo] ----------
     [echo] Handling BuildConfig class...
[buildconfig] No need to generate new BuildConfig.

-pre-compile:

-compile:
    [javac] Compiling 1 source file to /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/bin/classes
    [javac] /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/src/com/example/myfirstapp/DisplayMessageActivity.java:9: package android.support.v4 does not exist
    [javac] import android.support.v4.NavUtils;
    [javac]                          ^
    [javac] /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/src/com/example/myfirstapp/DisplayMessageActivity.java:36: cannot find symbol
    [javac] symbol  : variable NavUtils
    [javac] location: class com.example.myfirstapp.DisplayMessageActivity
    [javac]                 NavUtils.navigateUpFromSameTask(this);
    [javac]                 ^
    [javac] 2 errors

Answer 1

您的导入语句不正确，应该是:

import  android.support.v4.app.NavUtils;