ViewPager实现带引导小圆点与自动跳转的引导界面

实现引导小圆点的方法其实很简单,可直接在布局上放置与引导页面等量的ImageView,然后在切换页面的时候更改图片资源就好了。这里顺便提一下,有些APP是干脆在制作引导页面图片的时候加上引导小圆点,这种方式显然最简单不过了,但是既然是附在图片上的,在切换的时候也是随着图片滑动的,显然看起来效果并不是很好,甚至在我们需要加入小圆点的切换动画时,那就更不能这么去做了。

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首先我们先来看看实现效果

ViewPager实现带引导小圆点与自动跳转的引导界面 

这里我们的小圆点图片资源是采用shape绘制的,这里我弄的很随便,所以很粗糙,如果觉得不是很美观那就自行修改吧。如果你是直接使用png资源的话,可直接跳过这一步。

shape_ring_black_normal.xml(黑色小圆环)

<?xml version="1.0" encoding="utf-8"?> 
 
 
   
 
   
 
   
 
 

shape_circle_blue_press.xml(蓝色小圆点)

<?xml version="1.0" encoding="utf-8"?> 
 
 
   
 
   
 
 

再来个选择器,直接用setSelected方法就可以切换图片了,为true是切换为shape_circle_blue_press.xml,否则为shape_ring_black_normal.xml,记得选择器的默认item一定要在最后,否则没有效果。你也可以直接在切换页面的时候替换图片资源。

selector_circle.xml(小圆点选择器)

<?xml version="1.0" encoding="utf-8"?> 
 
 
   
   
 
 

页面布局很简单,ViewPage是重点来显示主要内容,再来一排ImageView显示小圆点,由于我们在最后一个页面需要有个按钮来跳转到主界面,这里我们加个Button先隐藏。

activity_guide.xml

<?xml version="1.0" encoding="utf-8"?> 
 
 
  

还有一步准备工作,添加每个页面的数据源,继承PagerAdapter这个类

GuideAdapter.java

import android.support.v4.view.PagerAdapter; 
import android.view.View; 
import android.view.ViewGroup; 
import java.util.List; 
 
public class GuideAdapter extends PagerAdapter { 
 
  private List mDatas; 
 
  public GuideAdapter(List datas) { 
    this.mDatas = datas; 
  } 
 
  @Override 
  public int getCount() { 
    return mDatas != null ? mDatas.size() : 0; 
  } 
 
  @Override 
  public Object instantiateItem(ViewGroup container, int position) { 
    container.addView(mDatas.get(position), 0); 
    return mDatas.get(position); 
  } 
 
  @Override 
  public void destroyItem(ViewGroup container, int position, Object object) { 
    container.removeView(mDatas.get(position)); 
  } 
 
  @Override 
  public boolean isViewFromObject(View view, Object object) { 
    return view == object; 
  } 
} 

接下来就看看如何实现,代码很简单,不难看懂,直接贴出来。

GuideAdapter.java

import android.content.Intent; 
import android.support.v4.view.ViewPager; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.Button; 
import android.widget.ImageView; 
import android.widget.RelativeLayout; 
 
import java.util.ArrayList; 
import java.util.List; 
 
public class GuideActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener { 
 
  private ViewPager vp; 
  private List mDatas = new ArrayList<>(); 
  private Button btn; 
  private GuideAdapter mGuideAdapter; 
 
  private int[] res = { 
      R.mipmap.ic_launcher, 
      R.mipmap.ic_launcher, 
      R.mipmap.ic_launcher 
  }; 
 
  private ImageView[] imgv = new ImageView[res.length]; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_guide); 
 
    initViews(); 
    initDatas(); 
    initEvents(); 
  } 
 
  private void initViews() { 
    vp = (ViewPager) findViewById(R.id.vp); 
    btn = (Button) findViewById(R.id.btn_goto); 
    imgv[0] = (ImageView) findViewById(R.id.imgv_circler1); 
    imgv[1] = (ImageView) findViewById(R.id.imgv_circler2); 
    imgv[2] = (ImageView) findViewById(R.id.imgv_circler3); 
    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT); 
    for (int i = 0; i < res.length; i++) { 
      ImageView imgv = new ImageView(this); 
      imgv.setLayoutParams(params); 
      imgv.setImageResource(res[i]); 
      mDatas.add(imgv); 
    } 
  } 
 
  private void initDatas() { 
    selectedDoto(0); 
    mGuideAdapter = new GuideAdapter(mDatas); 
    vp.setAdapter(mGuideAdapter); 
  } 
 
  private void selectedDoto(int index) { 
    for (int i = 0; i < res.length; i++) { 
      if (i == index) { 
        imgv[i].setSelected(true); 
      } else { 
        imgv[i].setSelected(false); 
      } 
    } 
  } 
 
  private void initEvents() { 
    vp.setOnPageChangeListener(this); 
    btn.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
        Intent intent = new Intent(GuideActivity.this, MainActivity.class); 
        startActivity(intent); 
        finish(); 
      } 
    }); 
  } 
 
  @Override 
  public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {} 
 
  @Override 
  public void onPageSelected(int position) { 
    if (position == res.length-1) // 如果是最后一个页面显示跳转按钮 
      btn.setVisibility(View.VISIBLE); 
    else 
      btn.setVisibility(View.GONE); 
    selectedDoto(position); 
  } 
 
  @Override 
  public void onPageScrollStateChanged(int state) {} 
} 

那如果每个页面不是一个控件这么简单呢?这时我们用Fragment,布局上还是差不多,但最后页面的按钮我们可以转移到最后一个Fragment布局上,因此直接删除Button,这里就不能继承Activity,要基础FragmentActivity。
接着我们就要弄三个Fragment出来,这里布局只简单放了个TextView,最后的页面还有个Button。我们就看看最后一个Fragment就好了。

fragment_guidec.xml

 
 
   
 
  

GuidecFragment.java

import android.content.Intent; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
 
public class GuidecFragment extends Fragment { 
 
  @Override 
  public View onCreateView(LayoutInflater inflater, ViewGroup container, 
               Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.fragment_guidec, container, false); 
    view.findViewById(R.id.btn_goto).setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
        Intent intent = new Intent(getActivity(), MainActivity.class); 
        startActivity(intent); 
        getActivity().finish(); 
      } 
    }); 
    return view; 
  } 
 
} 

当然在前面用到的Adapter是用不了了,这里需要继承FragmentPagerAdapter类。

GuideAdapter.java

import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentPagerAdapter; 
import java.util.List; 
 
public class GuideAdapter extends FragmentPagerAdapter { 
 
  private List mDatas; 
 
  public GuideAdapter(FragmentManager fm, List datas) { 
    super(fm); 
    this.mDatas = datas; 
  } 
 
  @Override 
  public Fragment getItem(int position) { 
    return mDatas.get(position); 
  } 
 
  @Override 
  public int getCount() { 
    return mDatas.size(); 
  } 
} 

GuideActivity.java

import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentActivity; 
import android.support.v4.view.ViewPager; 
import android.support.v7.app.AppCompatActivity; 
import android.widget.ImageView; 
 
import java.util.ArrayList; 
import java.util.List; 
 
public class GuideActivity extends FragmentActivity implements ViewPager.OnPageChangeListener { 
 
  private ViewPager vp; 
  private List mDatas = new ArrayList<>(); 
  private GuideAdapter mGuideAdapter; 
 
  private int[] res = { 
      R.mipmap.ic_launcher, 
      R.mipmap.ic_launcher, 
      R.mipmap.ic_launcher 
  }; 
 
  private ImageView[] imgv = new ImageView[res.length]; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_guide); 
 
    initViews(); 
    initDatas(); 
    initEvents(); 
  } 
 
  private void initViews() { 
    vp = (ViewPager) findViewById(R.id.vp); 
    imgv[0] = (ImageView) findViewById(R.id.imgv_circler1); 
    imgv[1] = (ImageView) findViewById(R.id.imgv_circler2); 
    imgv[2] = (ImageView) findViewById(R.id.imgv_circler3); 
  } 
 
  private void initDatas() { 
    selectedDoto(0); 
    mDatas.add(new GuideaFragment()); 
    mDatas.add(new GuidebFragment()); 
    mDatas.add(new GuidecFragment()); 
    mGuideAdapter = new GuideAdapter(getSupportFragmentManager(), mDatas); 
    vp.setAdapter(mGuideAdapter); 
  } 
 
  private void selectedDoto(int index) { 
    for (int i = 0; i < res.length; i++) { 
      if (i == index) { 
        imgv[i].setSelected(true); 
      } else { 
        imgv[i].setSelected(false); 
      } 
    } 
  } 
 
  private void initEvents() { 
    vp.setOnPageChangeListener(this); 
  } 
 
  @Override 
  public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {} 
 
  @Override 
  public void onPageSelected(int position) { 
    selectedDoto(position); 
  } 
 
  @Override 
  public void onPageScrollStateChanged(int state) {} 
} 

实现效果如下:

ViewPager实现带引导小圆点与自动跳转的引导界面       ViewPager实现带引导小圆点与自动跳转的引导界面

从上面还可以看到一个倒计时,那是怎么实现倒计时自动跳转呢?我们可以直接开个线程完成倒计时操作,当计时为0时便自动跳转,但用户很可能会回滑到上一个界面,也可能用户会手动点击跳转按钮进行跳转,因此,要把控好线程的关闭与开启。代码贴出来如下:

public void AutoGotoThread(boolean start) { 
  if (start) { 
    mGotoMainThread = new GotoMainThread(); 
    mGotoMainThread.start(); 
  } else { 
    if (mGotoMainThread != null && mGotoMainThread.isAlive()) { 
      mGotoMainThread.stopThread(); 
    } 
  } 
} 
 
private void startActivity() { 
  Intent intent = new Intent(getActivity(), MainActivity.class); 
  startActivity(intent); 
  mGotoMainThread.stopThread(); 
  getActivity().finish(); 
} 
 
private class GotoMainThread extends Thread { 
  private volatile boolean isRun = true; 
  private Object lock = new Object(); 
 
  @Override 
  public void run() { 
    synchronized (lock) { 
      while (isRun) { 
        try { 
          Message msg = Message.obtain(); 
          msg.what = 101; 
          msg.obj = "跳转 " + mTimeValues--; 
          mHandler.sendMessage(msg); 
          sleep(1000); 
        } catch (InterruptedException e) { 
          e.printStackTrace(); 
        } 
 
      } 
    } 
  } 
 
  public void stopThread() { 
    mTimeValues = 5; 
    isRun = false; 
  } 
} 
 
final Handler mHandler = new Handler() { 
  public void handleMessage(Message msg) { 
    switch (msg.what) { 
      case 101: 
        btn.setText((String) msg.obj); 
        if (mTimeValues < 0) { 
          startActivity(); 
        } 
        break; 
    } 
  } 
}; 

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持创新互联。


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