自定义View-6 状态按钮 滑动 点击

public class SwitchButton extends View implements OnClickListener, OnTouchListener {    private Context mContext;    private Bitmap mSwitchBottom, mSwitchThumb, mSwitchFrame, mSwitchMask;    private float mCurrentX = 0;    /**开关状态*/    private boolean mSwitchOn = true;    /**最大移动距离*/    private int mMoveLength;    /**第一次按下的有效区域*/    private float mLastX = 0;    /**绘制的目标区域大小*/    private Rect mDest = null;    /**截取源图片的大小*/    private Rect mSrc = null;    /**移动的偏移量*/    private int mDeltX = 0;    private Paint mPaint = null;    private OnChangeListener mListener = null;    private boolean mFlag = false;    public SwitchButton(Context context) {        this(context, null);    }    public SwitchButton(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public SwitchButton(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        this.mContext = context;        mSwitchBottom = BitmapFactory.decodeResource(getResources(), R.drawable.switch_bottom);        mSwitchThumb = BitmapFactory.decodeResource(getResources(), R.drawable.switch_btn_pressed);        mSwitchFrame = BitmapFactory.decodeResource(getResources(), R.drawable.switch_frame);        mSwitchMask = ((BitmapDrawable) getResources().getDrawable(R.drawable.switch_mask)).getBitmap();//两种方式都行        mMoveLength = mSwitchBottom.getWidth() - mSwitchFrame.getWidth();        mSrc = new Rect();        mDest = new Rect(0, 0, mSwitchFrame.getWidth(), mSwitchFrame.getHeight());        mPaint = new Paint();        mPaint.setAntiAlias(true);        mPaint.setAlpha(255);        mPaint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));        setOnClickListener(this);        setOnTouchListener(this);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {//这里的大小是写死的，所以布局中任何宽高的设置都是无效的！        setMeasuredDimension(mSwitchFrame.getWidth(), mSwitchFrame.getHeight());    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        if (mDeltX > 0 || mDeltX == 0 && mSwitchOn) {            if (mSrc != null) mSrc.set(mMoveLength - mDeltX, 0, mSwitchBottom.getWidth() - mDeltX, mSwitchFrame.getHeight());        } else if (mDeltX < 0 || mDeltX == 0 && !mSwitchOn) {            if (mSrc != null) mSrc.set(-mDeltX, 0, mSwitchFrame.getWidth() - mDeltX, mSwitchFrame.getHeight());        }        //这儿是离屏缓冲，自己感觉类似双缓冲机制吧        int count = canvas.saveLayer(new RectF(mDest), null, Canvas.MATRIX_SAVE_FLAG | Canvas.CLIP_SAVE_FLAG | Canvas.HAS_ALPHA_LAYER_SAVE_FLAG                | Canvas.FULL_COLOR_LAYER_SAVE_FLAG | Canvas.CLIP_TO_LAYER_SAVE_FLAG);        canvas.drawBitmap(mSwitchBottom, mSrc, mDest, null);        canvas.drawBitmap(mSwitchThumb, mSrc, mDest, null);        canvas.drawBitmap(mSwitchFrame, 0, 0, null);        canvas.drawBitmap(mSwitchMask, 0, 0, mPaint);        canvas.restoreToCount(count);    }    @Override    //onTouchListener的onTouch优先级比onTouchEvent高，会先触发。若onTouch返回false会接着触发onTouchEvent，反之onTouchEvent方法不会被调用！    public boolean onTouch(View paramView, MotionEvent paramMotionEvent) {        return false;//内置诸如click事件的实现等等都基于onTouchEvent，假如onTouch返回true，这些事件将不会被触发    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {        case MotionEvent.ACTION_DOWN:            mLastX = event.getX();            break;        case MotionEvent.ACTION_MOVE:            mCurrentX = event.getX();            mDeltX = (int) (mCurrentX - mLastX);            // 如果开关开着向左滑动，或者开关关着向右滑动（这时候是不需要处理的）            if ((mSwitchOn && mDeltX < 0) || (!mSwitchOn && mDeltX > 0)) {                mFlag = true;                mDeltX = 0;            }            if (Math.abs(mDeltX) > mMoveLength) mDeltX = mDeltX > 0 ? mMoveLength : -mMoveLength;            invalidate();            return true;        case MotionEvent.ACTION_UP:            if (Math.abs(mDeltX) > 0 && Math.abs(mDeltX) < mMoveLength / 2) {                mDeltX = 0;                invalidate();                return true;            } else if (Math.abs(mDeltX) > mMoveLength / 2 && Math.abs(mDeltX) <= mMoveLength) {                mDeltX = mDeltX > 0 ? mMoveLength : -mMoveLength;                mSwitchOn = !mSwitchOn;                if (mListener != null) mListener.onChange(this, mSwitchOn);                invalidate();                mDeltX = 0;                return true;            } else if (mDeltX == 0 && mFlag) {                //这时候得到的是不需要进行处理的，因为已经move过了                mDeltX = 0;                mFlag = false;                return true;            }            return super.onTouchEvent(event);        default:            break;        }        invalidate();        return super.onTouchEvent(event);    }    @Override    public void onClick(View v) {        mDeltX = mSwitchOn ? mMoveLength : -mMoveLength;        mSwitchOn = !mSwitchOn;        if (mListener != null) mListener.onChange(this, mSwitchOn);        invalidate();        mDeltX = 0;    }    //自定义的回调    public interface OnChangeListener {        public void onChange(SwitchButton sb, boolean state);    }    public void setOnChangeListener(OnChangeListener listener) {        mListener = listener;    }}

public class MainActivity extends Activity implements OnChangeListener {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_mybutton);        SwitchButton button = new SwitchButton(this);        button.setOnChangeListener(this);        ((LinearLayout) findViewById(R.id.root)).addView(button);    }    @Override    public void onChange(SwitchButton sb, boolean state) {        Toast.makeText(this, "状态：" + state, Toast.LENGTH_SHORT).show();    }}<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:gravity="center"    android:id="@+id/root"    android:orientation="horizontal" >    <com.bqt.myview.SwitchButton        android:layout_width="wrap_content"        android:layout_marginRight="20dp"        android:layout_height="100dp" /></LinearLayout>