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Android 天气预报图文字幕垂直滚动效果

 


       在很多天气或者新闻的应用中,我们都能看到一些字幕滚动的效果,最简单的实现为跑马灯效果,用系统提供的属性即可实现. 复杂一些的就需要自己去用自定义控件实现. 比如 让TextView 实现垂直滚动. 这里我要讲的是垂直滚动的字幕效果,并且内容并不仅为文字,还可以加入图片或者其他元素. 废话不多说,还是直接上效果图:

   


  


首先还是看一下核心的实现:

目前我的做法是重写了ScrollView,对外提供几个重要的方法:

isScrolled()方法判断当前是否为滚动状态

setScrolled(boolean flag)设置滚动的开关

setPeriod(long period)设置从开始滚动到结束的时间

setSpeed(long speed)设置滚动的速度

 


下面说一些需要注意的地方:

1.由于是定时操作,所以需要在Activity的对应生命周期进行处理: 当界面由不可见到可见时,设置setScrolled(true)打开滚动开关,由可见到不可见时,setScrolled(false)


关闭开关

2. 可根据自己需要调用setPeriod(long period)和setSpeed(long speed)控制滚动的速度

3. 由于是ScrollView实现的,中间放置的内容同ScrollView,不仅仅可以设置文字,还可以添加图片等其他元素,实现复杂的UI

4. 图文混排, 目前这个DEMO我还没做细致处理. 最主要的部分就是文字的处理,需要考虑中英文,全角半角,字体大小,段落处理,计算对应的字符宽高等进行排版

    图片等资源处理的部分就相对要简单,主要处理分辨率与计算宽高


    关于这些部分,之后我会慢慢做细致讲解.

这个Demo是我临时写的,UI和图文混排包括具体的滚动部分处理都相对简单,大家可以在这个例子的基础上进行扩展,根据需求做出自己想要的效果:

 

 

 

下面是对应的代码:

首先是自定义View:

 

[java]
package com.tony.autoscroll; 
 
 
import android.content.Context; 
import android.os.Handler; 
import android.util.AttributeSet; 
import android.util.Log; 
import android.view.MotionEvent; 
import android.widget.ScrollView; 
 
 
/**
 * @author Tony
 *
 */ 
public class AutoScrollView extends ScrollView { 
    private final Handler handler = new Handler(); 
     private long duration     = 50; 
     private boolean isScrolled   = false; 
    private int currentIndex = 0; 
    private long period = 1000; 
    private int  currentY = -1; 
    private double  x; 
    private double  y; 
    private int type = -1; 
    /**
     * @param context
      */ 
     public AutoScrollView(Context context) { 
        this(context, null); 
    } 
     
     /**
      * @param context
     * @param attrs
      */ 
    public AutoScrollView(Context context, AttributeSet attrs) { 
         this(context, attrs, 0); 
    } 
     
    /**
      * @param context
       * @param attrs
       * @param defStyle
       */ 
    public AutoScrollView(Context context, AttributeSet attrs, int defStyle) { 
        super(context, attrs, defStyle); 
     } 
     
    public boolean onTouchEvent(MotionEvent event) { 
         int Action = event.getAction(); 
        switch (Action) { 
            case MotionEvent.ACTION_DOWN: 
                x=event.getX(); 
                y=event.getY(); 
                 if (type == 0) { 
                     setScrolled(false); 
                                } 
                 break; 
             case MotionEvent.ACTION_MOVE: 
                double moveY = event.getY() - y; 
                 double moveX = event.getX() - x; 
                  
                if ((moveY>20||moveY<-20) && (moveX < 50 || moveX > -50) && getParent() != null) { 
                     getParent().requestDisallowInterceptTouchEvent(true);   
                                 } 
             
                 break; 
            case MotionEvent.ACTION_UP: 
                 if (type == 0) { 
                     currentIndex = getScrollY(); 
                    setScrolled(true); 
                } 
                break; 
            default: 
                break; 
        } 
                  return super.onTouchEvent(event);   
       } 
         @Override   
         public boolean onInterceptTouchEvent(MotionEvent p_event)   
        {   
          
            return true;   
        }   
    /**
      * 判断当前是否为滚动状态
      * 
      * @return the isScrolled
      */ 
     public boolean isScrolled() { 
        return isScrolled; 
     } 
     
     /**
      * 开启或者关闭自动滚动功能
      * 
      * @param isScrolled true为开启,false为关闭
      */ 
     public void setScrolled(boolean isScrolled) { 
        this.isScrolled = isScrolled; 
        autoScroll(); 
     } 
     
     /**
      * 获取当前滚动到结尾时的停顿时间,单位:毫秒
      * 
      * @return the period
      */ 
    public long getPeriod() { 
        return period; 
     }  
     
    /**
      * 设置当前滚动到结尾时的停顿时间,单位:毫秒
      * 
      * @param period
      *  the period to set
     */ 
    public void setPeriod(long period) { 
         this.period = period; 
     } 
     
      /**
      * 获取当前的滚动速度,单位:毫秒,值越小,速度越快。
       * 
      * @return the speed
      */ 
     public long getSpeed() { 
        return duration; 
     } 
     
     /**
      * 设置当前的滚动速度,单位:毫秒,值越小,速度越快。
      * 
      * @param speed
      *            the duration to set
      */ 
     public void setSpeed(long speed) { 
         this.duration = speed; 
     } 
     public void setType(int type){ 
         this.type = type; 
     } 
     private void autoScroll() { 
         handler.postDelayed(new Runnable() { 
            @Override 
             public void run() { 
                boolean flag = isScrolled; 
                 if (flag) { 
                    if (currentY == getScrollY()) { 
                         try { 
                            Thread.sleep(period); 
                        } catch (InterruptedException e) { 
                            e.printStackTrace(); 
                        } 
                        currentIndex = 0; 
                         scrollTo(0, 0); 
                        handler.postDelayed(this, period); 
                    } else { 
                        currentY = getScrollY(); 
                        handler.postDelayed(this, duration); 
                        currentIndex++; 
                        scrollTo(0, currentIndex * 1); 
                    } 
                } else { 
                                       //currentIndex = 0;  
                                       //scrollTo(0, 0);  
                } 
            } 
        }, duration); 
    } 

package com.tony.autoscroll;


import android.content.Context;
import android.os.Handler;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ScrollView;


/**
 * @author Tony
 *
 */
public class AutoScrollView extends ScrollView {
 private final Handler handler = new Handler();
  private long duration     = 50;
  private boolean isScrolled   = false;
 private int currentIndex = 0;
 private long period = 1000;
 private int  currentY = -1;
 private double x;
 private double  y;
 private int type = -1;
   /**
  * @param context
   */
  public AutoScrollView(Context context) {
  this(context, null);
 }
 
  /**
   * @param context
  * @param attrs
   */
 public AutoScrollView(Context context, AttributeSet attrs) {
   this(context, attrs, 0);
 }
 
  /**
   * @param context
    * @param attrs
    * @param defStyle
    */
 public AutoScrollView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  }
 
  public boolean onTouchEvent(MotionEvent event) {
   int Action = event.getAction();
   switch (Action) {
    case MotionEvent.ACTION_DOWN:
    x=event.getX();
     y=event.getY();
     if (type == 0) {
      setScrolled(false);
                                }
     break;
    case MotionEvent.ACTION_MOVE:
    double moveY = event.getY() - y;
     double moveX = event.getX() - x;
    
    if ((moveY>20||moveY<-20) && (moveX < 50 || moveX > -50) && getParent() != null) {
      getParent().requestDisallowInterceptTouchEvent(true); 
                                 }
   
     break;
   case MotionEvent.ACTION_UP:
     if (type == 0) {
      currentIndex = getScrollY();
     setScrolled(true);
                }
    break;
    default:
     break;
  }
                  return super.onTouchEvent(event); 
    }
      @Override 
      public boolean onInterceptTouchEvent(MotionEvent p_event) 
     { 
  
         return true; 
     } 
  /**
    * 判断当前是否为滚动状态
   *
   * @return the isScrolled
   */
  public boolean isScrolled() {
  return isScrolled;
  }
 
  /**
   * 开启或者关闭自动滚动功能
   *
   * @param isScrolled true为开启,false为关闭
   */
  public void setScrolled(boolean isScrolled) {
  this.isScrolled = isScrolled;
  autoScroll();
  }
 
   /**
   * 获取当前滚动到结尾时的停顿时间,单位:毫秒
   *
   * @return the period
   */
  public long getPeriod() {
  return period;
  }
 
 /**
   * 设置当前滚动到结尾时的停顿时间,单位:毫秒
   *
   * @param period
   *  the period to set
  */
  public void setPeriod(long period) {
   this.period = period;
  }
 
    /**
   * 获取当前的滚动速度,单位:毫秒,值越小,速度越快。
    *
   * @return the speed
   */
  public long getSpeed() {
  return duration;
   }
 
  /**
   * 设置当前的滚动速度,单位:毫秒,值越小,速度越快。
   *
   * @param speed
   *            the duration to set
   */
  public void setSpeed(long speed) {
   this.duration = speed;
  }
  public void setType(int type){
   this.type = type;
  }
  private void autoScroll() {
   handler.postDelayed(new Runnable() {
   @Override
    public void run() {
    boolean flag = isScrolled;
     if (flag) {
     if (currentY == getScrollY()) {
       try {
        Thread.sleep(period);
      } catch (InterruptedException e) {
        e.printStackTrace();
       }
      currentIndex = 0;
       scrollTo(0, 0);
      handler.postDelayed(this, period);
      } else {
      currentY = getScrollY();
       handler.postDelayed(this, duration);
      currentIndex++;
       scrollTo(0, currentIndex * 1);
     }
    } else {
                                       //currentIndex = 0;
                                       //scrollTo(0, 0);
    }
   }
  }, duration);
 }
}


MainActivity:


[java]
package com.tony.autoscroll; 
 
import com.example.testautoscroll.R; 
 
import android.os.Bundle; 
import android.app.Activity; 
 
/**
 * link: blog.csdn.net/t12x3456
 * @author Tony
 *
 */ 
public class MainActivity extends Activity { 
 
    private AutoScrollView scrollView; 
     
     
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 
     
        scrollView = (AutoScrollView) findViewById(R.id.auto_scrollview); 
    } 
 
    @Override 
    protected void onStart() { 
        // TODO Auto-generated method stub  
         
        if(!scrollView.isScrolled()){ 
            scrollView.setScrolled(true); 
        } 
        super.onStart(); 
    } 
     
    @Override 
    protected void onStop() { 
        // TODO Auto-generated method stub  
         
        if(scrollView.isScrolled()){ 
            scrollView.setScrolled(false); 
        } 
        super.onStop(); 
    } 

package com.tony.autoscroll;

import com.example.testautoscroll.R;

import android.os.Bundle;
import android.app.Activity;

/**
 * link: blog.csdn.net/t12x3456
 * @author Tony
 *
 */
public class MainActivity extends Activity {

 private AutoScrollView scrollView;
 
 
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
 
  scrollView = (AutoScrollView) findViewById(R.id.auto_scrollview);
 }

 @Override
 protected void onStart() {
  // TODO Auto-generated method stub
  
  if(!scrollView.isScrolled()){
   scrollView.setScrolled(true);
  }
  super.onStart();
 }
 
 @Override
 protected void onStop() {
  // TODO Auto-generated method stub
  
  if(scrollView.isScrolled()){
   scrollView.setScrolled(false);
  }
  super.onStop();
 }
}

 

http://www.bkjia.com/Androidjc/537976.htmlwww.bkjia.comtruehttp://www.bkjia.com/Androidjc/537976.htmlTechArticle在很多天气或者新闻的应用中,我们都能看到一些字幕滚动的效果,最简单的实现为跑马灯效果,用系统提供的属性即可实现. 复杂一些的就...

本文源自: AG88环亚

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