博客

图片轮播使用的容器是ViewPager，文字轮播使用的是TextSwitcher。

图片轮播的主要思路：利用Timer和TimerTask构建定时任务；监听ViewPager的滑动，根据滑动百分比动态改变指示小圆点的宽度和水平位移，达到拉伸和平移效果；触发MotionEvent.ACTION_DOWN时，停止定时任务；触发MotionEvent.ACTION_UP时重启定时任务；触发MotionEvent.ACTION_MOVE计算位移量，判断点击事件触发条件；

package com.example.autoplayview;

import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;

import java.util.Timer;
import java.util.TimerTask;

public class AutoPlayView extends RelativeLayout {
    private Context mContext;
    private ViewPager mPager;
    private LinearLayout dots;//计数小原点的布局
    private RelativeLayout indicator;//指示小原点
    private int width;//10dp（标准）
    private int dotWidth;//指示小原点的宽度
    private int dotDx;//指示小原点水平位移
    private LayoutParams mParams;//指示小原点布局参数（改变参数制作动画）
    private int current = 0;//当前页码
    private boolean canPlay;//可否播放
    private boolean isRunning;//是否正在播放；
    private int pageSize=0;//轮播数量
    private boolean isFirst = true;//第一次启动，为避免空指针问题，所以延迟0.2秒启动
    private Timer timer;
    private TimerTask timerTask;
    private float x;//用于判断是否为水平滑动
    private float y;//用于判断是否为竖直滑动
    private boolean isMove;//滑动不触发点击事件
    private long touchTime; //按下的时间
    private long hold;//按住了多久
    private ClickListener mListener;//点击事件

    public AutoPlayView(Context context) {
        this(context, null, 0);
    }

    public AutoPlayView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public AutoPlayView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.mContext = context;
        width = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 10,
                getResources().getDisplayMetrics());
        dotWidth = width;
        initView();
        initListener();

    }
    private void initView(){
       //图片容器ViewPager
       mPager = new ViewPager(mContext);
       RelativeLayout.LayoutParams lp01 = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
       this.addView(mPager, lp01);
       //计数小圆点
       dots = new LinearLayout(mContext);
       dots.setId(R.id.auto_play_dots);//添加自定义id（res/value/ids）
       RelativeLayout.LayoutParams lp02 = new RelativeLayout.LayoutParams(
               RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
       lp02.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
       lp02.setMargins(0, 0, 0, width);
       lp02.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);
       this.addView(dots, lp02);
       //指示小圆点
       indicator = new RelativeLayout(mContext);
       indicator.setBackgroundResource(R.drawable.dot_indicator);
       RelativeLayout.LayoutParams lp03 = new LayoutParams(width, width);
       lp03.addRule(RelativeLayout.ALIGN_BOTTOM, R.id.auto_play_dots);//相对定位
       lp03.addRule(RelativeLayout.ALIGN_LEFT, R.id.auto_play_dots);//相对定位
       this.addView(indicator, lp03);
   }

    private void initListener() {
        mPager.setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()) {
                    case MotionEvent.ACTION_UP:
                        hold = System.currentTimeMillis() - touchTime;
                        startPlay();
                        if (hold < 800 && mListener != null && !isMove) {//按住小于0.8秒，点击事件不为空，不是滑动状态，则触发点击
                            mListener.onClick(current);
                        }
                        break;
                    case MotionEvent.ACTION_DOWN: