Android自定义星星可滑动评分控件

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <declare-styleable name="StarRatingView">
    <!--星星点亮-->
    <attr name="stat_on" format="reference"></attr>
    <!--星星关闭-->
    <attr name="stat_off" format="reference"></attr>
    <!--半颗星星-->
    <attr name="stat_half" format="reference"></attr>
    <!--是否可以点击滑动评分-->
    <attr name="ratable" format="boolean"></attr>
    <!--星星之间间距-->
    <attr name="star_padding" format="dimension"></attr>
  </declare-styleable>

</resources>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:star="http://schemas.android.com/apk/res/com.le.star"
  android:id="@+id/activity_main"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:gravity="center_horizontal">
  <com.le.star.StarRatingView
    android:id="@+id/srv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    star:stat_on="@drawable/frodo_rate_star_small_on_holo_light"
    star:stat_off="@drawable/frodo_rate_star_small_off_holo_light"
    star:stat_half="@drawable/frodo_rate_star_small_half_holo_light"
    star:star_padding="10dp"
    star:ratable="false"
    >
  </com.le.star.StarRatingView>

  <Button
    android:id="@+id/btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    android:layout_below="@id/srv"
    android:text="click"
    />

  <TextView
    android:id="@+id/tv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="50dp"
    android:layout_below="@id/btn"
    android:textSize="20sp"
    />
  <com.le.star.StarRatingView
    android:id="@+id/srv_ratable"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/tv"
    android:layout_marginTop="20dp"
    star:stat_on="@drawable/frodo_rate_star_big_on_holo_light"
    star:stat_off="@drawable/frodo_rate_star_big_off_holo_light"
    star:stat_half="@drawable/frodo_rate_star_big_half_holo_light"
    star:star_padding="10dp"
    star:ratable="true"
    >
  </com.le.star.StarRatingView>


</RelativeLayout>

public class StarRatingView extends LinearLayout{
  private Drawable on,off,half;  //星星三种图片
  private boolean ratable;  //是否点击滑动
  private float padding; //星星之间间距
  private List<ImageView> list;  //存放五颗星星
  private float points[] = new float[11];  //0-10分点的x坐标，index为分数，值为此分数为坐标
  private float starWidth;  //设置的星星图片宽度
  private float halfStarWidth;  //半个星星宽度
  private int paddingLeft;    //控件左padding
  private OnRateChangeListener onRateChangeListener;

  public StarRatingView(Context context) {
    super(context);
  }

  public StarRatingView(Context context, AttributeSet attrs) {
    super(context, attrs);
    TypedArray array = context.obtainStyledAttributes(attrs,R.styleable.StarRatingView);
    on = array.getDrawable(R.styleable.StarRatingView_stat_on);
    off = array.getDrawable(R.styleable.StarRatingView_stat_off);
    half = array.getDrawable(R.styleable.StarRatingView_stat_half);
    ratable = array.getBoolean(R.styleable.StarRatingView_ratable, false);
    halfStarWidth = on.getIntrinsicWidth() / 2;
    starWidth = on.getIntrinsicWidth();
    padding = array.getDimension(R.styleable.StarRatingView_star_padding, starWidth / 3);
    paddingLeft = getPaddingLeft();
    list = new ArrayList<>();
    ImageView imageView;
    //初始化五个星星，并通过points数组把分数与坐标对应起来
    for(int i=0;i<5;i++){
      imageView = new ImageView(context);
      LinearLayout.LayoutParams layoutParams = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
      if(i!=0&&i!=4) {
        //设置间距
        layoutParams.setMargins((int) padding / 2, 0, (int) padding / 2, 0);
        //分数点所在的x坐标
        points[i*2] = i*starWidth+i*padding;
        points[i*2+1] = points[i*2]+halfStarWidth/2;
      }
      //第一个左边和最后一个右边不设置间距
      if(i==0){
        layoutParams.setMargins(0, 0, (int) padding / 2, 0);
        points[0] = 0;
        points[1] = halfStarWidth;
      }
      if(i==4){
        layoutParams.setMargins((int) padding / 2, 0, 0, 0);
        points[i*2] = i*starWidth+i*padding;
        points[i*2+1] = points[i*2]+halfStarWidth/2;
        points[10] = points[9]+halfStarWidth/2;
      }
      imageView.setLayoutParams(layoutParams);
      imageView.setImageDrawable(off);
      list.add(imageView);
      addView(list.get(i));
    }
    setOrientation(LinearLayout.HORIZONTAL);
    array.recycle();
  }

  /**
   *根据分数显示星星
   * @param rate
   */
  public void setRate(int rate){
    removeAllViews();
    int count = rate/2;
    boolean isOdd;
    if(rate%2==0){
      isOdd = false;
    }else{
      isOdd = true;
    }
    for(int i=0;i<list.size();i++){
      if(i<count){
        list.get(i).setImageDrawable(on);
      }else{
        list.get(i).setImageDrawable(off);
      }
      if(isOdd&&i==count){
        list.get(i).setImageDrawable(half);
      }
      addView(list.get(i));
    }
    if(ratable&&onRateChangeListener!=null){
      onRateChangeListener.onRateChange(rate);
    }
  }

  public void setOnRateChangeListener(OnRateChangeListener l){
    onRateChangeListener = l;

  }

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    //设置不可以滑动则不处理事件
    if(!ratable){
      return super.onTouchEvent(event);
    }
    setRate(calculateStar(event.getX()));
    return true;
  }

  /**
   * 根据坐标计算分数
   * @param x
   * @return
   */
  private int calculateStar(float x) {
    //减去控件左padding
    float realPosition = x-paddingLeft;
    for(int i = 0;i<points.length;i++){
      if(points[i]>realPosition){
        return i;
      }
    }
    //如果循环结束即为右滑超出最大值，返回10分
    return 10;
  }

  /**
   * 评分改变的回调
   */
  public interface OnRateChangeListener{
    void onRateChange(int rate);
  }
}

public class MainActivity extends AppCompatActivity {

 private int count;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  final StarRatingView srv = (StarRatingView) findViewById(R.id.srv);
  findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    count++;
    srv.setRate(count);
   }
  });
  final TextView tv = (TextView) findViewById(R.id.tv);
  StarRatingView srv_ratable = (StarRatingView) findViewById(R.id.srv_ratable);
  srv_ratable.setOnRateChangeListener(new StarRatingView.OnRateChangeListener() {
   @Override
   public void onRateChange(int rate) {
    tv.setText(rate+"分");
   }
  });
 }

}