Android Studio中无法解析fragmentActivity和ViewPager进口 [英] Android Studio Can't resolve fragmentActivity and ViewPager imports

问题描述

我按照开发滑动展示标签的教程。当我输入：

 进口android.support.v4.app.FragmentActivity;
进口android.support.v4.view.ViewPager;
 

Android的工作室给我看不能解析符号ViewPager和FragmentActivity。
如何解决此问题？谢谢。

下面是我的项目的整个code。

 进口android.app.ActionBar;
进口android.app.ActionBar.Tab;
进口android.app.FragmentTransaction;
进口android.os.Bundle;
进口android.support.v4.app.FragmentActivity;
进口android.support.v4.view.ViewPager;公共类MainActivity扩展FragmentActivity工具
    ActionBar.TabListener {私人ViewPager viewPager;
私人TabsPagerAdapter mAdapter;
私人动作条动作条;
//标签标题
私有String []选项卡= {最高评分，游戏，电影};@覆盖
保护无效的onCreate（捆绑savedInstanceState）{
    super.onCreate（savedInstanceState）;
    的setContentView（R.layout.activity_main）;    //动初始化
    viewPager =（ViewPager）findViewById（R.id.pager）;
    动作条= getActionBar（）;
    mAdapter =新TabsPagerAdapter（getSupportFragmentManager（））;    viewPager.setAdapter（mAdapter）;
    actionBar.setHomeButtonEnabled（假）;
    actionBar.setNavigationMode（ActionBar.NAVIGATION_MODE_TABS）;    //添加标签
    对于（字符串TAB_NAME：标签）{
        actionBar.addTab（actionBar.newTab（）的setText（TAB_NAME）
                .setTabListener（本））;
    }    / **
     *上刷卡viewpager做出选择相应的标签
     * * /
    viewPager.setOnPageChangeListener（新ViewPager.OnPageChangeListener（）{        @覆盖
        公共无效使用onPageSelected（INT位置）{
            //上改变页面
            //使受人尊敬的选项卡中选择
            actionBar.setSelectedNavigationItem（位置）;
        }        @覆盖
        公共无效onPageScrolled（INT为arg0，ARG1浮球，诠释ARG2）{
        }        @覆盖
        公共无效onPageScrollStateChanged（INT为arg0）{
        }
    }）;
}@覆盖
公共无效onTabReselected（标签选项卡，FragmentTransaction英尺）{
}@覆盖
公共无效onTabSelected（标签选项卡，FragmentTransaction英尺）{
    //在选项卡中选择
    //秀推崇片段视图
    viewPager.setCurrentItem（tab.getPosition（））;
}@覆盖
公共无效onTabUnselected（标签选项卡，FragmentTransaction英尺）{
}}
 

解决方案

1. 确保您已使用SDK管理器下载了Android的支持库。


2. 打开文件的build.gradle您的应用程序。



3. 支持库添加到依赖关系部分。例如，要添加V4支持库，加上下面几行：

   依赖性{
       ...
       编译com.android.support:support-v4:18.0.+
   }

I follow the tutorial of developing swipe-able tabs. When I import:

import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;

Android Studio shows me cannot resolve the symbol "ViewPager" and "FragmentActivity". How to solve this? thanks.

Below is the entire code of my project.

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;

public class MainActivity extends FragmentActivity implements
    ActionBar.TabListener {

private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
// Tab titles
private String[] tabs = { "Top Rated", "Games", "Movies" };

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

    // Initilization
    viewPager = (ViewPager) findViewById(R.id.pager);
    actionBar = getActionBar();
    mAdapter = new TabsPagerAdapter(getSupportFragmentManager());

    viewPager.setAdapter(mAdapter);
    actionBar.setHomeButtonEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Adding Tabs
    for (String tab_name : tabs) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                .setTabListener(this));
    }

    /**
     * on swiping the viewpager make respective tab selected
     * */
    viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            // on changing the page
            // make respected tab selected
            actionBar.setSelectedNavigationItem(position);
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
        }

        @Override
        public void onPageScrollStateChanged(int arg0) {
        }
    });
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // on tab selected
    // show respected fragment view
    viewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}

}

解决方案

1. Make sure you have downloaded the Android Support Repository using the SDK Manager.
2. Open the build.gradle file for your application.

3. Add the support library to the dependencies section. For example, to add the v4 support library, add the following lines:

   dependencies { ... compile "com.android.support:support-v4:18.0.+" }

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