Android编程实现可滑动的开关效果(附demo源码下载)

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package com.lxb.switchdemo;
import android.content.Context;
import android.graphics.Color;
import android.os.Handler;
import android.os.Message;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.Animation.AnimationListener;
import android.view.animation.LinearInterpolator;
import android.view.animation.TranslateAnimation;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;
public class SwitchView extends LinearLayout implements OnClickListener {
  private static final int FLAG_MOVE_TRUE = 1; // 向左滑动标识
  private static final int FLAG_MOVE_FALSE = 2; // 向右滑动标识
  private static final int HANDLE_LAYOUT_CURSOR = 100; // 处理调用开关的layout方法
  private Context context; // 上下文对象
  private RelativeLayout sv_container; // SwitchView的外层Layout
  private ImageView iv_switch_cursor; // 开关邮标的ImageView
  private TextView switch_text_true; // true的文字信息控件
  private TextView switch_text_false; // false的文字信息控件
  private boolean isChecked = true; // 是否已开
  private boolean checkedChange = false; // isChecked是否有改变
  private OnCheckedChangeListener onCheckedChangeListener; // 用于监听isChecked是否有改变
  private int margin = 1; // 游标离边缘位置(这个值视图片而定, 主要是为了图片能显示正确)
  private int bg_left; // 背景左
  private int bg_right; // 背景右
  private int cursor_left; // 游标左部
  private int cursor_top; // 游标顶部
  private int cursor_right; // 游标右部
  private int cursor_bottom; // 游标底部
  private Animation animation; // 移动动画
  private int currentFlag = FLAG_MOVE_TRUE; // 当前移动方向flag
  public SwitchView(Context context) {
    super(context);
    this.cOntext= context;
    initView();
  }
  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    super.onLayout(changed, l, t, r, b);
    // 获取所需要的值
    bg_left = sv_container.getLeft();
    bg_right = sv_container.getRight();
    cursor_left = iv_switch_cursor.getLeft();
    cursor_top = iv_switch_cursor.getTop();
    cursor_right = iv_switch_cursor.getRight();
    cursor_bottom = iv_switch_cursor.getBottom();
  }
  private Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      switch(msg.what) {
      case HANDLE_LAYOUT_CURSOR:
        iv_switch_cursor.layout(cursor_left, cursor_top, cursor_right, cursor_bottom);
        break;
      }
    }
  };
  public void onClick(View v) {
    // 控件点击时触发改变checked值
    if(v == this) {
      changeChecked(!isChecked);
    }
  }
  /**
   * 初始化控件
   */
  private void initView() {
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View view = inflater.inflate(R.layout.switch_view, this);
    view.setOnClickListener(this);
    sv_cOntainer= (RelativeLayout) view.findViewById(R.id.sv_container);
    switch_text_true = (TextView) view.findViewById(R.id.switch_text_true);
    switch_text_false = (TextView) view.findViewById(R.id.switch_text_false);
    changeTextColor();
    iv_switch_cursor = (ImageView) view.findViewById(R.id.iv_switch_cursor);
    iv_switch_cursor.setClickable(false);
    iv_switch_cursor.setOnTouchListener(new OnTouchListener() {
      int lastX; // 最后的X坐标
      public boolean onTouch(View v, MotionEvent event) {
        switch(event.getAction()) {
        case MotionEvent.ACTION_DOWN:
          lastX = (int) event.getRawX();
          cursor_left = v.getLeft();
          cursor_top = v.getTop();
          cursor_right = v.getRight();
          cursor_bottom = v.getBottom();
          break;
        case MotionEvent.ACTION_MOVE:
          int dx = (int) event.getRawX() - lastX;
          cursor_left = v.getLeft() + dx;
          cursor_right = v.getRight() + dx;
          // 超出边界处理
          if(cursor_left <= bg_left + margin) {
            cursor_left = bg_left + margin;
            cursor_right = cursor_left + v.getWidth();
          }
          if(cursor_right >= bg_right - margin) {
            cursor_right = bg_right - margin;
            cursor_left = cursor_right - v.getWidth();
          }
          v.layout(cursor_left, cursor_top, cursor_right, cursor_bottom);
          lastX = (int) event.getRawX();
          break;
        case MotionEvent.ACTION_UP:
          calculateIscheck();
          break;
        }
        return true;
      }
    });
  }
  /**
   * 计算处于true或是false区域, 并做改变处理
   */
  private void calculateIscheck() {
    float center = (float) ((bg_right - bg_left) / 2.0);
    float cursor_center = (float) ((cursor_right - cursor_left) / 2.0);
    if(cursor_left + cursor_center <= center) {
      changeChecked(true);
    } else {
      changeChecked(false);
    }
  }
  /**
   * 改变checked, 根据checked移动游标
   * @param isChecked
   */
  private void changeChecked(boolean isChecked) {
    if(this.isChecked != isChecked) {
      checkedChange = true;
    } else {
      checkedChange = false;
    }
    if(isChecked) {
      currentFlag = FLAG_MOVE_TRUE;
    } else {
      currentFlag = FLAG_MOVE_FALSE;
    }
    cursorMove();
  }
  /**
   * 游标移动
   */
  private void cursorMove() {
    // 这里说明一点, 动画本可设置animation.setFillAfter(true)
    // 令动画进行完后停在最后位置. 但这里使用这样方式的话.
    // 再次拖动图片会出现异常(具体原因我没找到)
    // 所以最后只能使用onAnimationEnd回调方式再layout游标
    animation = null;
    final int toX;
    if(currentFlag == FLAG_MOVE_TRUE) {
      toX = cursor_left - bg_left - margin;
      animation = new TranslateAnimation(0, -toX, 0, 0);
    } else {
      toX = bg_right - margin - cursor_right;
      animation = new TranslateAnimation(0, toX, 0, 0);
    }
    animation.setDuration(100);
    animation.setInterpolator(new LinearInterpolator());
    animation.setAnimationListener(new AnimationListener() {
      public void onAnimationStart(Animation animation) {
      }
      public void onAnimationRepeat(Animation animation) {
      }
      public void onAnimationEnd(Animation animation) {
        // 计算动画完成后游标应在的位置
        if(currentFlag == FLAG_MOVE_TRUE) {
          cursor_left -= toX;
          cursor_right = cursor_left + iv_switch_cursor.getWidth();
        } else {
          cursor_right = bg_right - margin;
          cursor_left = cursor_right - iv_switch_cursor.getWidth();
        }
        // 这里不能马上layout游标正确位置, 否则会有一点点闪屏
        // 为了美观, 这里迟了一点点调用layout方法, 便不会闪屏
        mHandler.sendEmptyMessageDelayed(HANDLE_LAYOUT_CURSOR, 5);
        // 这里是根据是不是改变了isChecked值进行一些操作
        if(checkedChange) {
          isChecked = !isChecked;
          if(onCheckedChangeListener != null) {
            onCheckedChangeListener.onCheckedChanged(isChecked);
          }
          changeTextColor();
        }
      }
    });
    iv_switch_cursor.startAnimation(animation);
  }
  /**
   * 改变字体显示颜色
   */
  private void changeTextColor() {
    if(isChecked) {
      switch_text_true.setTextColor(Color.WHITE);
      switch_text_false.setTextColor(Color.GRAY);
    } else {
      switch_text_true.setTextColor(Color.GRAY);
      switch_text_false.setTextColor(Color.WHITE);
    }
  }
  /**
   * layout游标
   */
  private void layoutCursor() {
    if(isChecked) {
      cursor_left = bg_left + margin;
      cursor_right = bg_left + margin + iv_switch_cursor.getWidth();
    } else {
      cursor_left = bg_right - margin - iv_switch_cursor.getWidth();
      cursor_right = bg_right - margin;
    }
    iv_switch_cursor.layout(cursor_left, cursor_top, cursor_right, cursor_bottom);
  }
  /**
   * isChecked值改变监听器
   */
  public interface OnCheckedChangeListener {
    void onCheckedChanged(boolean isChecked);
  }
  public boolean isChecked() {
    return isChecked;
  }
  public void setChecked(boolean isChecked) {
    if(this.isChecked != isChecked) {
      this.isChecked = isChecked;
      if(onCheckedChangeListener != null) {
        onCheckedChangeListener.onCheckedChanged(isChecked);
      }
      layoutCursor();
    }
  }
  public void setOnCheckedChangeListener(
      OnCheckedChangeListener onCheckedChangeListener) {
    this.OnCheckedChangeListener= onCheckedChangeListener;
  }
}

package com.lxb.switchdemo;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import com.lxb.switchdemo.SwitchView.OnCheckedChangeListener;
public class Switch_demoActivity extends Activity implements OnClickListener {
  private LinearLayout layout;
  private TextView tv_showcheck;
  private SwitchView sv;
  private Button btn_set_true;
  private Button btn_set_false;
  private Button btn_getstate;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    layout = (LinearLayout) findViewById(R.id.layout);
    tv_showcheck = (TextView) findViewById(R.id.tv_showcheck);
    sv = new SwitchView(this);
    tv_showcheck.setText("当前状态: " + getState(sv.isChecked()));
    sv.setOnCheckedChangeListener(new OnCheckedChangeListener() {
      public void onCheckedChanged(boolean isChecked) {
        tv_showcheck.setText("当前状态: " + getState(isChecked));
      }
    });
    layout.addView(sv);
    btn_set_true = (Button) findViewById(R.id.btn_set_true);
    btn_set_false = (Button) findViewById(R.id.btn_set_false);
    btn_getstate = (Button) findViewById(R.id.btn_getstate);
    btn_set_true.setOnClickListener(this);
    btn_set_false.setOnClickListener(this);
    btn_getstate.setOnClickListener(this);
  }
  public void onClick(View v) {
    switch(v.getId()) {
    case R.id.btn_set_true:
      sv.setChecked(true);
      break;
    case R.id.btn_set_false:
      sv.setChecked(false);
      break;
    case R.id.btn_getstate:
      Toast.makeText(Switch_demoActivity.this,
          sv.isChecked() + "", Toast.LENGTH_SHORT).show();
      break;
    }
  }
  private String getState(boolean state) {
    if(state) {
      return "开";
    }
    return "关";
  }
}