eclipse 中的 appcompat_v7 错误

Question

我是 android 编程新手。我刚刚安装了 eclipse、sdk 和 adt 插件。当我导入其他项目时，evereting 工作正常。但是当我创建一个新项目时，它给了我很多错误。

以下是错误：

*Description    Resource    Path    Location    Type
Unknown error: java.lang.NullPointerException   appcompat_v7        Unknown Android Packaging Problem

*ActionBarActivity cannot be resolved to a type MainActivity.java   /Testsaid/src/com/example/testsaid  line 32 Java Problem

*The method getMenuInflater() is undefined for the type MainActivity    MainActivity.java   /Testsaid/src/com/example/testsaid  line 19 Java Problem

*R cannot be resolved to a variable MainActivity.java   /Testsaid/src/com/example/testsaid  line 19 Java Problem

*The method onOptionsItemSelected(MenuItem) of type MainActivity must override or implement a supertype method  MainActivity.java   /Testsaid/src/com/example/testsaid  line 24 Java Problem
error: Error retrieving parent for item: No resource found that matches the given name 'Theme.AppCompat.Light'. styles.xml  /Testsaid/res/values    line 7  Android AAPT Problem
*R cannot be resolved to a variable MainActivity.java   /Testsaid/src/com/example/testsaid  line 29 Java Problem
*The method onCreateOptionsMenu(Menu) of type MainActivity must override or implement a supertype method    MainActivity.java   /Testsaid/src/com/example/testsaid  line 17 Java Problem
error: Error retrieving parent for item: No resource found that matches the given name 'Theme.AppCompat.Light'. styles.xml  /Testsaid/res/values-v11    line 7  Android AAPT Problem
*R cannot be resolved to a variable MainActivity.java   /Testsaid/src/com/example/testsaid  line 13 Java Problem
*ActionBarActivity cannot be resolved to a type MainActivity.java   /Testsaid/src/com/example/testsaid  line 12 Java Problem
*The method onCreate(Bundle) of type MainActivity must override or implement a supertype method MainActivity.java   /Testsaid/src/com/example/testsaid  line 11 Java Problem
*ActionBarActivity cannot be resolved to a type MainActivity.java   /Testsaid/src/com/example/testsaid  line 8  Java Problem
*The import android.support.v7 cannot be resolved   MainActivity.java   /Testsaid/src/com/example/testsaid  line 3  Java Problem
*error: Error retrieving parent for item: No resource found that matches the given name 'Theme.AppCompat.Light.DarkActionBar'.  styles.xml  /Testsaid/res/values-v14    line 8  Android AAPT Problem

这里是主要活动的代码：

package com.example.saidg;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

我注意到它们中的大多数来自 values 文件夹。它们标有一个小红叉

我还注意到已经创建了一个名为 appcompat 的新项目。我看到了关于这个问题的其他帖子，但他们没有帮助。目标 sdk 已在项目属性文件中设置为 android 21。

谢谢

Answer 1

前往

Right click your Project --> Properties --> Android --> 
(on the right side Library Section) (Click) Add --> Select appcompat_v7 (click ok and Apply)

现在清理并构建所有项目。

Answer 2

您可以在不创建活动的情况下创建新项目。 --> 取消勾选创建活动。

或者正常创建项目。这将创建新的 Appcompat 文件夹。然后，您可以删除新的并从项目的属性中将库更改为旧的。

另一种可能的错误是与 Android 支持库冲突。您可以从项目文件夹内的 libs 文件夹中删除它。